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To renew call Telephone Center, 333-8400 Digitized by the Internet Archive in 2016 with funding from University of Illinois Urbana-Champaign Alternates https://archive.org/details/moultriecountyso110hopk SST/ / iT* UNIVERSITY OF ILLINOIS AGRICULTUE/L EXPERIMENT station SOIL EFFORT 1-10 1911-15 URBANA, ILLINOIS i>6 <■> ■Vur, \ - \ 0 CONT^TTS 1 Clay county soils 2 Moultrie county soils 3 Hardin county soils 4 Sangamon county soils 6 La Salle county soils 6 Knox county soils 7 McDonough county soils 8 Bond county soils 9 Lake county soils 10 McLean county soils UNIVERSITY OF ILLINOIS agriculture library ,A •Il>o7G2 I UNIV^S'TY OF ILLINOIS , LIBRARY UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 1 CLAY COUNTY SOILS By CYRIL, G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and J. E. READHIMER URBANA, ILLINOIS, MARCH, 1911 State Advisory Committee on Soil Investigations Ralph Allen, Delavan F. I. Mann, Gilman A. N. Abbott, Morrison J. P. Mason, Elgin E. W. Burroughs, Edwardsville Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief in Agronomy and Chemistry Soil Survey — J. G. Mosier, Assistant Chief A. F. Gustafson, Assistant C. C. Logan, Assistant S. V. Holt, Assistant H. W. Stewart, Assistant H. C. Wheeler, Assistant Soil Analysis — J. H. Pettit, Assistant Chief E. VanAlstine, Assistant J. P. Aumer, Assistant Gertrude Niederman, Assistant W. H. Sachs, Assistant Frances D. Abbott, Assistant W. R. Leighty, Assistant Soil Experiment Fields — J. E. Readhimer, Superintendent Wm. G. Eckhardt, Assistant O. S. Fisher, Assistant J. E. Whitchurch, Assistant E. E, Hoskins, Assistant V'- UNIVERSITY OF ILLINOIS BdRICULTURE LIBRARY CLAY COUNTY SOILS By CYRIL G. HOPKINS, J. G. MOSIER, J. H. PETTIT and J. E. READHIMER Introduction The Illinois County Soil Reports, beginning with Report No. i, “Clay County Soils,” constitute a series of publications separate and distinct from the bulletins and circulars of the Experiment Station. At least three of these county reports will be sent to the Station’s entire mailing list. These three are the reports of Clay County, representing the common soils of south- ern Illinois; Moultrie County, representing the common corn belt soils; and Hardin County, representing the unglaciated Ozark Hills region. As a rule the other soil reports will be sent only to the residents of the respective coun- ties, and to others upon request. This plan requires that each county report shall be as complete as practicable, and consequently this general discussion of soil principles, which appears as an introduction in the Clay County Re- port, may be found with any necessary modifications as an appendix to every other county report. A study of the soil map and the tabular statements concerning crop re- quirements, the plant food content of the different soil types, and the actual results secured from definite field trials with different methods or systems ot soil improvement, and a careful study of the discussion of general prin- ciples and of the descriptions of individual soil types will furnish the most necessary and useful information for the practical improvement and perma- nent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and important soil types in the great soil areas in all parts of Illinois is contained in Bulle- tin No. 123, “The Fertility in Illinois Soils,” which contains a colored gen- eral survey soil map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils.” Bulletin No. 94, “Nitrogen Bacteria and Legumes.” Bulletin No. 99, “Soil Treatment for the Lower Illinois Glaciation.” Bulletin No. 1 15, “Soil Improvement for the Worn Hill Lands of Illinois.” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois.” Circular No. no, “Ground Limestone for Acid Soils.” Circular No. 127, “Shall we use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers.” Circular No. 149, “Some Results of Scientific Soil Treatment” and “Methods and Re- sults of Ten Years’ Soil Investigation in Illinois.” NOTE. — Information as to where to obtain limestone, phosphate, bone meal and oo- tasstum salts, methods of application, etc., will also be found in Circular no. 2 Soil Report No. i [March, Soil Survey Methods The detail soil survey of a county consists essentially of indicating on a map the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish, this object three things are essential: first, careful, well-trained men to do the work; second, an ac- curate base map upon which to show the results of their work; and, third, the means necessary to enable the men to place the soil type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal varieties and lim- its, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will survey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries will match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil map- ping. The base map c are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construction of these maps, while the most trustworthy county map available is used in locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and corrected if wrongly located. In order to make these verifications and corrections, each survey party is provided with an odometer for measuring distances, and a plane table for determining the directions of roads, rail- roads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field, and the soil type boundaries, additional streams, and necessary corrections are placed with proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils being carried in the field for this purpose. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is taken by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions.' Distances along roads are measured by an odometer attached to the axle of the vehicle, while dis- tances in . the field off the roads are determined by pacing, an art in which the ‘men become expert by practice. The soil boundaries can thus be lo- cated with as high a degree of accuracy as can be indicated by pencil on tin scale of one inch to the mile. Clay County 3 1911] Soil Characteristics The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between ad- joining types is usually distinct, but sometimes one type will grade into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, alluvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) the structure, or the depth and character of the surface, subsur- face, and subsoil; (4) the physical or mechanical composition of the differ- ent strata composing the soil, as the percentages of gravel, sand, silt, clay, and organic matter which they contain; (5) the texture, or porosity, granu- lation, friability, plasticity, etc.; (6) the color of the strata; (7) the natural drainage; (8) agricultural value, based upon its natural productiveness; (9) native vegetation; (10) the ultimate chemical composition and re- action. The common soil constituents are indicated in the following outline: Constituents of Soils Soil Constituents Organic Matter Inorganic Matter t Comprising undecomposed and partially decayed ( vegetable material Clay 001 mm.* and less Silt 001 mm. to .03 mm. Sand 03 mm. to 1. mm. Gravel 1. mm. to 32 mm. Stones 32. mm. and over. *25 millimeters equal 1 inch. Further discussion of these constituents is given in Circular 82. Groups oe Soil Types The following gives the different general groups of soils : Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand and silt and a little clay. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and some silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Soil Report No. [March, Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 25 to 50 percent gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no agricultural value. More or less organic matter is found in nearly all of the above classes. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which this is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases tho exceed- ingly important is not a positive, but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but the rate of liberation is governed by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are lime- stone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may also be supplied by green manure crops and crop residues, such as clover, cowpeas, straw, and cornstalks. The rate of decay of organic matter de- pends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which repre- sents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre corresponds to nearly 20 tons of organic matter. But this organic matter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20 tons of old inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent ad- ditions of active organic matter, whether in applications of farm manure, in legume crops, or in grass root sods of old pastures. Probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even though plowed alike and at the same time, prepared the same way, planted the same day Clay County s 1911] with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that the produc- tive power of the land depends primarily upon the stock of plant food con- tained in the soil and upon the rate at which it is liberated, just as the suc- cess of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such commodity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, seme nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing nitrates, phosphates, and other salts of potas- sium, magnesium, calcium, etc., for the use of the growing crop. As already explained, fresh organic matter decomposes much more rap- idly than the old humus, which represents the organic residues most resistant to decay and which consequently have accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid decomposition or oxidation of the organic matter, and also by incorporating with the old resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and which thus furnish or liberate organic matter and inorganic food for bacteria, which, under such favorable con- ditions appear to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when incorporated with fresh farm manure, so that when used together, two tons of the mixture may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bacterial action is also promoted by the presence of lime- stone. It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches among our common agricultural plants) secure six elements from the soil (phosphorus, potassium, magnesium, calcium, iron, and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of these plant-food elements in just the same sense that a building is made of wood and iron, brick, stone, and mortar. Without 6 Soil Report No. [March, materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in southern Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay ; and, where the land is properly drained and properly tilled, such crops would frequently be secured if the plant foods were pres- ent in sufficient amount and- liberated at a sufficiently rapid rate to meet the absolute needs of the crops. Crop Requirements The accompanying table shows the requirements of such crops for the five most important plant food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are not known ever to limit the yield of crops) : Table 1 — Plant Pood in Wheat, Corn, Oats, and Clover Produce Nitro- Phos- Potas- Magne- Cal- gen, phorus, sium, sium, cium, Kind Amount pounds pounds pounds pounds pounds Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw lYz tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs Yz ton 2 2 Oats, grain 100 bu. 66 .11 16 4 2 Oat straw 2 Yz tons 31 5 52 7 IS Clover seed 4 bu. 7 2 3 1 1 Clover hay 4 tons 160 20 120 31 117 Total in grain and seed 244* 42 51 16 4 Total in four crops . . . . 510* 77 322 68 168 To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as pos- sible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the 100-bushel crop of corn. is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has pro- duced, as an average of the six years, 1905 to 1910, a yield of 87 bushels of corn per acre in grain fanning (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with limestone, phosphorus, and manure). On the Edgewood Experiment Field, less than five miles from the north line of Clay County, and on the common prairie land of southern Illinois, yields have been obtained as high as 91 bushels per acre of corn, 74 bushels of oats, and 2.91 tons of air-dry clover hay, in the first cutting, and prob- ably more than 1 ton in the second crop, which, however, was plowed under without weighing. *These amounts include the nitrogen contained in the clover seed or hay, which, however, may be secured from the air. EFFINGHAM COUNTY HivLaAVjI AiIiNi IOO H m z SOIL SURVEY MAP OF CLAY COUNTY UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Clay County 7 1911] THE FERTILITY IN CLAY COUNTY SOILS Origin of Soil Material Clay County was covered by the Illinoisan ice sheet, which generally leveled down hills and filled valleys, and left that part of the state as a broad level expanse broken only by a few morainal or preglacial ridges, remnants of which now form our ridge soils. The ice sheet in its move- ment southward carried large amounts of earthy material of various sizes, including boulders, gravel, sand, silt and clay, which were deposited when the ice melted, forming what is known as till, boulder clay, or glacial drift, which may be recognized readily by its composite character. After the ice sheet melted, the surface of the glacial drift was slowly and gradually changed into a soil which varied somewhat as soils do now. At the close of the Iowan glaciation, which followed the Illinoisan, the entire state was covered with a wind-blown dust, known as loess, which was deposited somewhat uniformly over this region to a depth of from 4 to 10 feet, burying the old soil completely. A new soil was formed from this fine material by the subsequent weathering and the accumulation of organic matter, which has been modified to form the present soils. The old buried soil, known as the Sangamon soil, is sometimes exposed along streams or roadsides, occasionally as a dark heavy stratum two or three feet thick, while in other places it is represented only by a weathered surface of the glacial drift. Table 2. — Son, Types of Clay County Soil type No. Names Area in acres Percent of total 330 (a) Upland Prairie Soils (Page 22) Gray silt loam on tight clay 110,720 37.000 328 Brown-gray silt loam on tight clay 960 .330 329 Drab silt loam 14,400 4.800 326.1 Brown silt loam on clay 824 .270 331 Deep gray silt loam 1,760 .590 332 (b) Upland Timber Soils (Page 26) Tight gray silt loam on tight clay 51,200 17.130 332.1 White silt loam on tight clay 224 .073 334 Yellow-gray silt loam 21,240 41,760 7.090 335 Y ellow silt loam 14.000 235 (c) Ridge Soils (Page 29) Y ellow silt loam 2,560 .854 233 Gray- red silt loam on tight clay , 9,180 3.000 1331 (d) Swamp and Bottom land Soils (Page 30) Deep gray silt loam 31,680 10.580 1361 Mixed sandy loam 12,800 4.270 1315 Drab clay 25 .008 1301 Deep peat 15 .005 'T'n+a Is 299,348 100.000 The data in Table 3 represent the total amounts of plant food found in 2 million* pounds of the surface soil, which corresponds to an acre of soil about 6 2 /z inches deep, including at least as much soil as is ordinarily turned with the plow, and representing that part of the soil with which we incorporate the farm manure, limestone, phosphate, or other fertilizer applied in soil im- provement. This is the soil stratum upon which we must depend in large *The amounts are for only 1 million pounds of the peat soil because its specific gravity is only one-half that of normal soils. Soil Report No. i [March, part to furnish the necessary plant food for the production of the crops grown. In Table 3 is recorded the invoice of the plowed soil, showing the total amounts of these five elements of plant food contained in each of the differ- ent types of soil in Clay County. (For more details see Bulletin 123.) Table 3 — Fertility in the Soils of Clay County, Illinois Average pounds per acre in 2 million pounds of surface soil (about 6% inches) Soil Total Total Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- calci- stone stone No. carbon gen phorus sium sium um present required Upland Prairie Soils 330 Gray silt loam on tight clay 26970 2790 750 24830 4690 3420 1130 328 Brown-gray silt loam on tight clay. . . 30600 3020 1020 25760 5780 4020 160 329 Drab silt loam 23640 2560 630 25110 4560 6270 1520 326.1 Brown silt loam on clay 30740 3320 700 24700 5520 7720 1500 331 Deep gray silt loam. . . . 20800 2180 600 24220 3000 4900 1640 Upland Timber Soils 332 Light-gray silt loam on tight clay. . . 17810 1580 760 27860 4310 4620 480 322.1 White silt loam on tight clay 16980 1120 400 29380 4940 4060 840 334 Yellow-gray silt loam. . . . 19600 1650 550 30200 5490 6920 40 335 Yellow silt loam 16990 1540 510 31430 3800 3000 2250 Ridge Soils 235 233 Y ellow silt loam Gray-red silt loam on tight clay. . . 41970 27380 3890 2720 820 760 29500 27300 8140 5200 6040 4320 140 1040 Swamp and Bottom-land Soils 1331 Deep gray silt loam .... 31470 2910 1350 34740 7700 7580 100 1361 Mixed sandy loam 26950 2700 750 31410 6350 7950 80 1315 Drab clay 43960 4180 1040 35300 10920 8160 40 1301 Deep peat* . . . 297660 16790 930 6190 7240 107900 224680 The importance of maintaining a rich surface soil cannot be too strongly emphasized. It is well illustrated by data from the Rothamsted Experi- ment Station, the oldest in the world. Thus on Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years, 1892 to 1901 were 12.3 bushels per acre on plot 3 (unfertilized) and 31.8 bushels on plot 7 (well fertilized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in plot 3 than in plot 7, thus showing that the higher yields from plot 7 were due to the fact that the plowed soil had been enriched. In 1893, plot 7 contained per acre in the surface soil (o to 9 inches) about 600 pounds more nitro- gen and 900 pounds more phosphorus than plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. * Amounts reported are from 1 million pounds of peat soil. EFFINGHAM R. 7 E < ol-NTY RICHLAND l-'^z ! SOIL SURVEY MAP OF CLAY COUNTY UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Clay County 9 1911 1 By easy computation it will be found that not one of the prairie soils of Clay County contains enough total nitrogen in the plowed soil for the pro- duction of maximum crops for ten rotations; while the upland timber soils contain as an average only about half as much nitrogen as the prairie land. Practically the same condition obtains with respect to phosphorus, only two of the eleven upland soils containing as much of that element as would be required for ten crop rotations if such crop yields were secured as sug- gested in Table 1 ; and in case of the cereals it will be seen that about three-fourths of the phosphorus taken from the soil is deposited in the grain, while only one-fourth remains in the straw or stalks. If only the grain and seed were sold from the farm the total supply of phosphorus in the plowed soil is no more than would need to leave the farm during the full time of one life (70 years). On the other hand, the potassium is sufficient for 2000 years, if only the grain is sold, or for 300 years if the total crops are removed; and the corresponding figures are about 1200 and 300 years for magnesium, and about 3000 and 100 years for calcium. Thus when measured by the actual crop requirements for plant food magnesium and calcium are more limited than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses* of Illinois well-waters drawn chiefly from glacial sands, grav- els, or till, 3 million pounds of water (about the average annual drainage per acre- for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of calcium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of mag- nesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as de- termined by analyzing the soil in 1865 and again in 1905. It is of interest to note that thirty crops of clover of 4 tons each would require 3510 pounds of calcium, while the most common prairie land (gray silt loam on tight clay) contains only 3420 pounds of total calcium in the plowed soil of an acre. These general statements relating to the total quantities of plant food in the plowed soil certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the need-s of large crop yields for even one or two generations of people. We must also consider, however, the question of the rate at which these plant food elements may be liberated and thus m*ide available for plant growth. Methods of Liberating Plant Food Limestone and decaying organic matter are the principal materials the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also of the nitrifying bacteria which have power to transform the insoluble and un- available o rganic nitrogen into soluble and available nitrate nitrogen. ♦Reported by Doctor Bartow and associates, of the Illinois State Water Survey. 10 Soil Report No. i [March, At the same time the products of this decomposition. have power to dis- solve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by per- mitting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds noth- ing whatever to the soil, but always leaves the soil poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root development and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to im- prove the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soie Improvement The best and most profitable methods for the permanent improvement of the common soils of Clay County are as follows : (1) Apply at least two tons (and better five tons) per acre of ground limestone, preferably at times magnesian limestone (CaC03 MgC03) which contains both calcium and magnesium, and has slightly greater power to correct soil acidity, ton for ton, than the ordinary cal- cium limestone (CaC 03 ). Afterward continue to apply about two tons per acre of ground limestone every four to six years. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks) or by using for feed and bedding practically all of the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in prices and seasons, but the follow- ing are suggested to serve as models or outlines : First year, corn (with some winter legume, such as red clover, alsike, sweet clover, or alfalfa, or a mixture, seeded on one-half of the field at the last cultivation). Second year, oats or barley on one-half and cowpeas or soybeans where the winter catch crop is plowed down. Third year, wheat or rye (with clover or clover and grass). Fourth year, (1) clover, or (2) clover and timothy, or (3) clover and red top. Fifth year, (1) wheat and clover, or (2) timothy and clover, or (3) red top. Sixth year, (1) clover, or (2) clover and timothy, or (3) red top. In grain farming, with wheat grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or in live-stock farming, the clover may be reseeded each spring, if necessary to maintain the stand, and the field used three years for timothy and clover pasture and meadow as desired. If red top is seeded the clover will usually make seed or both hay and seed the fourth year, and red-top seed may be sold the fifth and sixth years. To avoid clover sickness it may sometimes be necessary to substitute red clover or alsike for the other in about every third rotation, and to discontinue their use in the catch- crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also Clay County 11 1911] be used as a catch-crop and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in: mind that the following amounts of nitrogen are required for the produce named : 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires i l / 2 pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of red top requires 21 pounds of nitrogen. 1 ton of average manure contains 10 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and more to cowpeas) than will be left in the roots and stubble. For grain crops, as wheat, corn, and oats, about two-thirds of the nitro- gen is contained in the grain and one-third in the straw or stalks. (3) On all of the lands not subject to overflow (or susceptible to serious erosion by surface washing or gullying) apply the element phos- phorus in considerably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far secured shows positively that fine-ground nat- ural rock phosphate can^be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil improvement. The first application may well be one ton per acre (at least one-half ton should be used), and subse- quently about one-half ton per acre every four to six years should be applied, at least until the phosphorus content of the plowed soil reaches 2000 pounds per acre, which will require a total application of five or six tons per acre of raw phosphate containing 12 percent of the element phosphorus. Steamed bone meal and even acid phos- phate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in southern Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in carload lots), more than 10 cents a pound in steamed bone meal, and more than 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phosphate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about i x / 2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate). The phosphate and limestone may be applied at any time during the rotation, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded, while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply of decaying organic matter has been made ade- quate, some temporary benefit may be derived from the use of a 12 Soil Report No. [March, soluble salt or mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as to furnish available potassium and mag- nesium, and for a few years such use of kainit will no doubt be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for de- caying organic matter, since this will necessitate returning to the soil either all produce except the grain (in grain farming) or the manure produced in live-stock farming. (Where hay or straw are sold, manure should be bought.) Table 4. — Fertility in the Soils of Clay County, Illinois Average pounds per acre in 4 million of subsurface soil (about 6-3 to 20 inches) Soil Total Total Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- cal- stone stone No. carbon gen phorus sium sium , cium present required Upland Prairie Soils 330 Gray silt loam on tight clay 28860 3420 1250 53910 13040 7620 6630 328 Brown-gray silt loam on tight clay . . . 18480 2320 1080 54280 11640 5080 6160 329 Drab silt loam 35780 2420 1160 « 50160 8840 11520 3760 326.1 Brown silt loam on clay 54800 5120 1360 48440 11520 13920 4920 331 Deep gray silt loam • 34680 3800 1320 49360 7320 7880 5760 Upland Timber Soils 332 Light-gray silt loam on tight clay. . . 9240 1620 1360 57180 13880 6920 13640 332.1 White silt loam on tight clay. . . 11600 1120 920 60200 10280 8120 8200 334 Yellow-gray silt loam . 13760 1520 860 64420 14100 7880 1680 335 Yellow-silt loam 15890 1830 790 64480 12720 6840 14270 Ridge Soils 235 Y ellow silt loam 48680 5000 1340 61040 23180 9300 12940 233 Gray-red silt loam on tight clay. . . 29000 3480 1240 60680 14880 7760 7880 Swamp and Bottom-land Soils 1331 Deep gray silt loam ■ . 25380 2760 2184 70480 15960 12880 1720 1361 Mixed sandy loam 31980 3060 1180 63220 10940 13220 200 1315 Drab clay. . . . 38480 3800 1360 71320 22440 16040 40 1301 Deep peat* . . . 595320 33580 1860 12380 14480 215800 449360 The Subsurface and Subsoil In Tables 4 and 5 are recorded the amounts of plant food in the subsur- face and subsoils, but it should be remembered that these supplies are of little va lue unless the top soil is kept rich. Probably the most important in- *Amounts reported are from 2 million pounds of deep peat. Clay County 13 1911] formation contained in Tables 4 and 5 is that all of the upland soils are even more strongly acid in the subsurface and subsoil than in the surface, thus emphasizing the importance of having plenty of limestone in the surface soil to neutralize the acid moisture which rises from the lower strata by capillary action during periods of partial drouth, which are also critical periods in the life of such plants as clover. Table 5.— Fertility in the Soils of Clay County, Illinois Average pounds per acre in 6 million pounds of subsoil ( about 20 to 40 inches ) So il type No. Soil type Total organic carbon Total nitro- gen Total phos- phorus 1 Total potas- sium Total mag- nesium Total cal- cium Dime- stone present Dime- stone re- quired Upland Prairie Soils 330 Gray silt loam on tight clay 20600 2980 2000 88620 33690 19830 20540 328 Brown-gray silt loam on tight clay. . . 12060 2340 2040 87420 33540 18720 4860 329 Drab silt loam 34020 2910 1470 77160 19020 17280 16440 326.1 Brown silt loam on clay 53700 5640 1260 69660 24480 26760 13200 331 Deep gray silt loam 24300 3540 1320 78720 17220 11040 17100 Upland Timber Soils 332 Dight gray silt loam on tight clay. . . 12680 1910 1830 88110 31420 13680 47060 332.1 White silt loam on tight clay. . . 11640 1620 1500 91800 15540 10920 25320 334 Y ellow-gray silt loam .... 13230 1950 1560 96270 29310 10770 20490 335 Y ellow silt loam 15200 1720 1160 92480 20760 11880 12280 Ridge Soils 235 Y ellow silt loam 26880 3450 1350 95790 31410 20100 10410 233 Gray-red silt loam on tight clay. . . 25020 3360 1800 87720 29280 16620 27360 Swamp and Bottom-land Soils 1331 Deep gray silt loam .... 19260 2470 2940 106300 24240 16620 6590 1361 Mixed sandy loam 20130 2100 1350 94350 16890 14760 4350 1315 Drab clay 33600 3660 2040 107040 35880 25680 60 1301 Deep peat* . . . 892980 50370 2790 18570 21720 323700 674040 On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow- gray silt loam, and the ridge soils (and even the gray silt loam prairie on rolling areas), the supply of minerals in the subsurface and subsoil tend to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently; but where such lands are farmed under such a system not more than two or three grain crops should be grown during a period of io or 12 years, the land being kept in pasture most of the time; and a liberal use of limestone, as top dressings if necessary, and occasional reseeding with clo vers will benefit both the pasture and indirectly the grain crops. * Amounts reported are from 3 million pounds of deep peat 14 Soil Report No. i [March, Table 6. — Crop Yields per Acre on DuBois Experiment Field On Prairie Land; Gray Silt Loam on Tight Clay Soil 1902 1903 1904 1905 1906 1907 1908 1909 treatment Corn Oats Wheat Clover Corn Oats Wheat Soybeans applied bu. bu. bu. tons bu. bu. bu. bu. Land not Tile-drained None 6 9 6 1.3 30 19 1 3.5 Lime 7 16 7 1.6 35 28 8 6.7 Lime, phosphorus. Lime, phosphorus, 13 26 25 2.4 39 44 18 8.5 and potassium .. . 12 30 28 2.9 49 50 21 9.5 Land Tile-drained None 1 17 3 1.3 33 13 4 3.3 Lime 3 17 12 1.7 34 24 11 6.2 Lime, phosphorus. Lime, phosphorus, 7 28 28 2.3 30 32 19 7.2 and potassium.. . 14 26 32 3.0 55 44 23 10.3 Average of Two Series None Lime Lime, phosphorus. Lime, phosphorus, and potassium. . . 4 5 10 13 13 17 27 28 5 9 27 30 1.3 1.7 2.4 2.9 31 34 34 52 16 26 38 47 10 19 22 3.4 6.5 7.9 9.9 Gain for lime and phosphorus 6 14 22 1.1 3 22 16 4.5 Value of increase.. $2.10 $4.20 $15.40 $6.60 $ 1.05 $6.60 $11.20 $4.50 Value of crops from untreated land $1.40 $3.40 $ 3.50 $7.80 $10.85 $4.80 $ 2.10 $3.40 Results of Field Experiments at Du Bois Before considering in detail the individual soil types, it seems advisable to study some of the results already obtained where definite systems of soil improvement have been given an actual trial in different parts of southern Illinois. In Table 6 are recorded some exceedingly valuable, trustworthy, inter- esting and instructive data. These results were secured by eight years of actual trial on the most common type of soil in Clay County, which is also a very common type in Washington County, where the DuBois Experiment Field is located. Anyone of common sense can understand this table if he is willing to study jt. Has tile-drainage been beneficial? There are 32 comparisons which bear upon the answer to this question, — 8 with no soil treatment, 8 with lime applied, 8 with lime and phosphorus, and 8 comparisons where lime, phos- phorus, and potassium were used ; and the average of these results certainly does not justify investing in tile drainage for this land. Does the application of lime and phosphorus produce benefit? The an- swer to this is found in the fact that the value of the eight crops on the untreated land amounted to only $3775, whereas the value of the increase produced by lime and phosphorus was $51.65. In other words, the treat- Clay County IS 1911] ment produced more than the land did, raising the crop values from $37-75 to $89.40, counting corn at 35 cents a bushel, oats at 30 cents, wheat at 70 cents, hay at $6.00 a ton, and soybeans at $1.00 a bushel, prices which are somewhat below the 10-year average. It should be stated, too, that marked improvement was made in quality (especially in wheat and clover), which is not given credit in these values. The materials used per acre in these experiments were 5 tons of burned lime (applied only at the beginning), 1600 pounds of steamed bone meal (800 pounds for each four-year rotation), and 800 pounds of potassium sulfate (400 pounds for each rotation) ; but other investigations (reported in Circulars no and 127) have shown that ground natural limestone and fine-ground natural rock phosphate are more economical and profitable forms of lime and phosphorus; and the effect produced by potassium sulfate can also be secured at much less expense either by means of decaying organic matter (from crop residues, green manure crops, or farm manure) or by the use of less expensive soluble salts, such as kainit, as shown below. If we allow $10 for ground limestone (which would pay for the full equivalent of the lime applied) and $20 for the bone meal (its actual cost), we find that the increase produced has paid for these materials and left a net profit of $2.70 per acre per annum, or 70 percent above the cost. Furthermore about one-half of the lime applied and at least two-thirds of the phosphorus applied still remain in the soil for the benefit of future crops. The potassium applied during the eight years cost $20 and produced increases valued at $19.55, leaving a loss of 6 cents per acre per annum, and furthermore the potassium removed is equal to the total amount ap- plied. On five other plots in the Du.Bois field commercial nitrogen was used alone or with other elements during the first three years, but at large finan- cial loss, and with no apparent residual effect. Since 1907, a system has been adopted for those plots which will supply both the nitrogen and or- ganic matter by means of legume catch crops and crop residues, but an- other rotation will be required to get this system underway so as to pro- duce any marked effect upon crop yields. Owing to the severe drouth in the summer of 1908, the clover failed on the DuBois field, and consequently soybeans were substituted. Results oe Field Experiments at Fairfield The accompanying photographic reproductions show more plainly than words or figures the effect and the importance of applying limestone and phosphorus to the common upland soil of southern Illinois. These photo- graphs were taken in 1910, and show four parts of a field which was all seeded alike to clover in 1909. This 40-acre experiment field is about one mile north of Fairfield, in Wayne County, which adjoins Clay County on the south. The Fairfield Experiment Field is divided into four tracts of land, and a four-year rotation is practiced, consisting of corn, cowpeas (or soybeans), wheat, and clover. If the clover fails, cowpeas or soybeans may be substi- tuted for that season ; and if the winter wheat fails, oats or barley may be substituted in the spring. One half of the field, or 20 acres, is tile-drained, while the other half has only the ordinary surface drainage, as commonly 16 Soil Report No. i [March, Plate 1.— Clover on Fairfield Experiment Field, 1910. (The first crop, shown IN PHOTOGRAPHS, WAS CLIPPED AND LEFT ON THE LAND; THE SECOND CROP PRODUCED NO CLOVER SEED ON THE UNTREATED LAND, BUT 1| BUSHELS WERE HARVESTED WHERE THE LIMESTONE AND PHOSPHATE WERE APPLIED) . provided by plowing in rather narrow lands and keeping the middle fur- rows open. Grain farming is practiced on half of the tiled land and also on half of the land not tiled ; while live-stock farming is practiced on the other half of each part. A part of each of these divisions is treated with 2 tons of limestone and i ton of fine-ground raw rock phosphate, per acre, every four years, while another part is not so treated. In the system of grain farming the plan is to return to the land all produce except the grain or seed, while in live-stock farming all produce (or its equivilent) is to be used for feed and bedding and the manure re- turned to the land in proportion to the crop yields produced during the previous rotation. It should be stated, however, that during the first rota- tion the manure was applied in the same amount (8 tons per acre) both where limestone and phosphate were used and where they were not used ; but in the second rotation, as when manure is applied to the 19 io clover ground for the 1911 corn crop, the application of manure will be in direct proportion to the crop yields produced during the preceding four years. Thus, if the land treated with limestone and phosphate has produced as an average, one- half larger crops of corn, cowpeas, oats, and clover during 1907, 1908, 1909, and 1910, then one-half more manure will be applied to that land for the 1911 corn crop, than to the land which receives manure alone. Like- wise the clover and other crop residues returned in the grain system during the second and subsequent rotations will be in proportion to the yield pro- duced on the respective parts of the field. Clay County 17 1911] Plate 2.— Clover on Fairfield Experiment Field, 1910. (The first crop, shown in PHOTOGRAPH, MADE 1 TON OF FOUL GRASS WITH BUT LITTLE CLOVER WHERE MANURE ALONE WAS USED, AND 2§ TONS OF CLEAN CLOVER HAY WHERE THE SAME AMOUNT OF MANURE WAS USED WITH LIMESTONE AND PHOSPHATE). The best plan is to apply the phosphate and plow it under with manure or other organic matter; and to apply the limestone immediately after the ground is plowed for wheat in order that it may be mixed with the sur- face soil in the preparation of the seed-bed where clover is to be seeded the following winter or spring. However, the time and method of appli- cation are very secondary matters; the important thing is to get the lime- stone and phosphate on the land and well mixed with the plowed soil, al- tho it is better to mix one with the soil before applying the other, because when applied in intimate contact the limestone tends temporarily to lessen the availability of the phosphorus, probably by immediately neutralizing the nitric, carbonic, and organic acids produced in the decay of organic matter. At $1.25 a ton for limestone, and $7.50 a ton for rock phosphate, the cost of those materials amounts to $10 an acre every four years; but after three or four rotations the phosphate application will be reduced to about one-half ton, which will reduce the annual expense to about $1.50 per acre, an expense which would be practically covered by an increase of 4 bushels of corn, i ]/ 2 bushels of cowpeas or soybeans, 2 bushels of wheat, 5 bushels of oats, or J4 ton of hay. In Table 7 are recorded the crop yields obtained since the work was be- gun on the land on which the 1910 clover fields are shown in the photo- graphs. On this field clover was sown without a nurse crop late in the season of 1905, and the 1906 hay crop was mostly red top, the land hav- ing been used as a red top meadow previously. 18 Soil Report No. i [March, Table 7 Crop Yields per Acre on Fairfield Experiment Field On Prairie Land: Gray silt Loam on Tight Clay Soil 1906 1907 1908 1909 1910 treatment Clover (?) Corn Cowpeas Oats Clover (?) applied tons bu. bu. bu. crops Land not Tile-drained Limestone and phosphorus .50 45.4 9.0 35.7 1.50 bu. None .20 34.2 5.3 29.9 .00 bu. Manure .39 42.1 7.4 34.2 1 .06 ton. Manure, limestone, phosphorus .48 52.4 9.4 40.9 3.50 tons. Land Tile-drained Limestone and phosphorus .12 39.0 7.7 33.0 .89 bu. None .10 32.1 4.7 25.8 .00 bu. Manure .25 35.3 5.4 30.8 .76 ton. Manure, limestone, phosphorus .44 49.5 11.5 37.3 3.62 tons. Average of both Tiled and Untiled Land Limestone and phosphorus None Manure .31 .15 .32 . 46 42.2 33.2 38.7 51.0 8.4 5.0 6.4 10.5 34.4 27.9 32.5 39.1 1.20 bu. .00 bu. .91 ton. 3.56 tons. Manure, limestone, phosphorus Average gain for limestone and phosphorus .15 10.6 3.8 6.5 ( 1.20 bu. (2.65 tons. Value of increase $ .90 $3.71 $3.80 | $1.95 j $ 7.20 j $15.90 Note Where no manure is applied the first cutting of clover is left on the land, the second cutting saved for seed, and the threshed clover straw returned to the land. The photographs show the 1910 fields in both the grain system and the live-stock sys- tem (first crop). The 4-inch tile were laid in the fall and winter of 1905-1906. They were placed only four rods apart, half of the strings about 20 to 24 inches deep and the other half about 36 to 40 inches deep, and they were covered with about 4 inches of cinders before the ditches were filled. They have a satisfactory grade and a good outlet is provided. The tiled land is some- what more nearly level than the untiled land, altho the entire field is what would be called level prairie land. While it is very possible that, with the continued use of clover (the “best subsoiler”) in the rotation, the tile drainage may ultimately prove to be a profitable investment, it is plain to see that the first requisites for the improvement of this soil are limestone, phosphorus, and organic matter. As an average of both systems of farming on both tiled and untiled land,, the increases produced by limestone and phosphorus during the first rota- tion have paid $10.36* an acre, or more than they cost delivered at the average railroad station in southern Illinois; and the increase in the two *Possibly this should be increased or decreased slightly because, as hereinafter re- ported, on one-half of the land under experiment potassium salts are applied; and, while they produce practically no effect on the manured land, the effect is very appreciable on the unmanured land; and altho the potassium salts are applied to one-half of the check plots the same as to one-half of the land receiving limestone and phosphorus, so that the $10.36' is the actual increase produced by the limestone and phosphorus above the return from land otherwise treated the same, nevertheless there is a possibility that on part of the land represented in this summary the effect of the potassium salts was different where used with limestone and phosphorus than where used alone. No potassium salts had been applied to the land where the photographs were taken or to the land from which the reported 1910 yields of clover hay or seed were secured. 101l\ Clay County 19 cuttings of clover hay in the first year of the second rotation has a value of $15.90, or more than enough to pay for the second application of both limestone and phosphate, thus leaving as net profit any increases that may be produced during the next three years; and these increases will be aug- mented because of the larger amount of organic manures to be returned to the better yielding land. In the grain system the limestone and phosphate produced 1.20 bushels of clover seed, valued at $7.20. * Wheat was seeded on this land in the fall of 1908, but it was winter- killed so completely that oats were seeded in the spring as a substitute. In 1908, wheat on another series of plots produced 4.1 bushels on untreated land, 13.7 bushels where limestone and phosphate had been used, 6.0 bush- els where manure had been applied for corn two years before, and 18.6 bush- els per acre where manure, limestone, and rock phosphate had been ap- plied, thus showing an average increase from limestone and phosphorus of 11. 1 bushels. In 1910, on still other series of plots the average increase from limestone and phosphorus was 17 1 bushels of wheat, 19 bushels of corn, and 7.7 bushels of soybeans. Advantage of Crop Rotation and Permanent Systems It should be noted that the clover is not likely to be well infected with the clover bacteria during the first rotation ; but even a partial stand of clover the first time will probably provide a thousand times as many bacteria for the next clover crop as one could afford to apply in artificial inoculation, for a single root tubercle may contain a million bacteria developed from one during the season’s growth. This is only one of several advantages of the second rotation over the first four years. Thus the mere practice of crop rotation is an advan- tage, especially in helping to rid the land of insects and foul grass and weeds. The deep-rooting clover crop is an advantage to subsequent crops because of that characteristic. The larger applications of organic manures are a great advantage; and in systems of permanent soil improvement, such as are here advised and illustrated, more limestone and more phosphorus are provided than are needed for the meager or moderate crops produced dur- ing the first rotation, and consequently the crops in the second rotation have the advantage of such accumulated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. Thus, with the crop yields shown in Table 7, it is safe to say that one-fourth of the limestone and more than four-fifths of the phos- phorus applied remain in the soil at the end of the first four years. This means that these systems tend positively toward the making of rich land from poor land — toward the making of $200 land out of $50 land. The ultimate analyses recorded in Tables 3, 4 and 5 give the absolute in- voice of these southern Illinois soils. They show that they are positively deficient only in limestone, phosphorus, and nitrogenous organic matter; and the accumulated information from careful and long-continued investi- gations in different parts of the United States positively establish the fact that in general farming these essentials can be supplied with greatest econ- omy and profit by the use of ground natural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. No other applications are absolutely necessary, but, as already explained, and as shown in Table 6, the addition of some soluble salt in the beginning of a system of improvement on these soils produces some 20 Soil Report No. i [March, temporary benefit, and if some inexpensive salt such as kainit is used it may produce sufficient increase to more than pay the added cost The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate being 200 pounds of potassium sulfate and molecular ecjuivalents of mag- nesium sulfate and sodium sulfate. As an average of 58 years (1852 to 1909) the yield of wheat has been 12.8 bushels on untreated land, 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied ; and, as further additions, 85 pounds of potas- sium raised the yield to 31.4 bushels; 52 pounds of magnesium raised it to 29.4 bushels; and 50 pounds of sodium raised it to 29.6 bushels. Where potassium was applied the average wheat crap removed 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table 1. The Rotham- sted soil contained abundance of limestone, but no organic matter was pro- vided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 58 years (1852 to 1909) has been 14.5 bushels on untreated land, 38.8 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus have been applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.7 bushels, but, where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average has been 43.4 bushels. Thus, as an average of 58 years, the use of sodium produced 1.8 bushels less wheat and 1.7 bushels more barley than the use of potas- sium. with both grain and straw removed and no organic manures returned. While about half of the potassium, nitrogen, and organic matter, and about one-fourth of the phosphorus, contained in manure, will be lost by three or four months’ exposure in the ordinary pile in the barn yard, there is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while the animals destroy two-thirds of the organic matter and retain one-fourth of the nitrogen and phosphorus in average live-stock farming, they retain less than one-tenth of the potassium, from the food consumed ; so that the actual loss of potassium in the pro- ducts sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potas- sium in the surface 6^3 inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage) would permanently maintain the potassium in grain farming by renewal from the subsoil, provided one-third of the potassium is removed by cropping be- fore the soil is carried away. Thus, aside from the peat soil, there is no soil in Clay County which contains less than 3,600 pounds of potassium per acre-inch. One-third of this is 1200 pounds, while 100 years of grain farm- ing would carry away from the farm only 1275 pounds of potassium in the grain and seed of such crops as are mentioned in Table 1. Clay County 21 1911] From all of these facts it will be seen that the potassium problem is not one of supply but of liberation ; and the Rothamsted records show that other sol- uble salts have practically the same power as potassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other elements, is not known, but where much potassium is removed, as in the entire crops at Rothamsted with no return of organic residues, probably the soluble salt functions in both ways. As an average of 84 separate tests conducted in 1907, 1908, and 1909, on the Fairfield Experiment Field, an application of 200 pounds of potas- sium sulfate, containing 85 pounds of potassium costing $5.10, increased the yield of corn by 7.9 bushels per acre; while 600 pounds of kainit, contain- ing only 60 pounds of potassium and costing $4.00, gave an increase of 10.6 bushels. Thus, at 40 cents a bushel for corn, the kainit has paid for itself; but these results, like those at Rothamsted and DuBois, were se- cured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield include an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm ma- nure had been applied. As an average of 84 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by .8 bushel while the 600 pounds of kainrt gave an increase of 1.1 bushels. Thus, where organic manure was supplied, practically no effect was produced by the addition of either potassium sulfate or kainit; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for; and perhaps in larger part because the decaying or- ganic matter helps to liberate and held in solution other plant food elements, especially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown that potassium salts and most other soluble salts increase the solubility of the phosphorus in soil and in rock phosphate as determined by chemical analysis; also that the addition of glucose with rock phosphate in pot-culture experiments increases the availability of the phosphorus, as meas- ured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the organic matter of the food consumed, it is easy to determine from Table 1 that more organic matter will be supplied in a proper grain sys- tem than in a strictly live-stock system ; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc. are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious in- terference with the capillary movement of the soil moisture, a common danger from plowing under too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming,, or when both grain and straw are sold, of course the draft on potassium will then be so great that in time it must be renewed by some sort of application. As a rule, such farmers ought to secure manure from town, since they furnish the bulk of the material out of which the manure is produced. 22 Soil Report No. [March, INDIVIDUAL SOIL TYPES (a) Upland Prairies Gray Silt Loam on Tight Clay ( jjo ) This is the predominating type of soil in the lower Illinoisan glaciation and greatly exceeds any other type in Clay County, the area being 100,720 acres, or 37 percent of the area of the county. Its topography is nearly level or gently undulating, tho in places somewhat rolling. The type variations* are due primarily to three things : ( 1 ) the organic matter content; (2) the topography and consequent surface drainage; and (3) the depth, thickness, and density of the tight clay layer. Adjoining the somewhat rolling areas or in the vicinity of ridges, this type has received some wash that has buried the tight clay to such depths that it is less ob- jectionable, and generally made it a better soil than the average. This is particularly noticeable in parts of Townships 3 and 4, Range 5. In some of the low areas that grade toward drab silt loam (329), or brown silt loam -on clay (326.1) the organic matter content is higher in the subsurface and subsoil, giving a better phase of the type. This fact is noticeable in certain areas in Townships 4 and 5, Range 7, and to a less ex- tent in small areas in Township 3, Range 6. The surface stratum, o to 6^ inches, consists of a friable, silt loam, varying from light to dark gray in color and containing sufficient clay to make it slightly plastic when wet. A few small gravels of quartz and concre- tions of hydrated iron oxid are sometimes found in it. The organic matter content varies somewhat from an average of 2.4 percent as determined from the total organic carbon. The surface soil is fairly pervious to water but the low organic matter content and lack of granulation render it in poor tilth, causing it to “run together” very readily from heavy rains or by freez- ing and thawing when wet. The subsurface soil, averaging about 13 inches in thickness, varies from a gray silt loam to a very light gray or even white silt. The upper part of this stratum is sometimes about the same in color as the surface soil, but much oftener the plowline marks the beginning of a much lighter colored soil, which becomes still lighter with depth, passing into a distinct “gray layer,” varying in thickness from 2 to 10 inches. This “gray layer” is deficient in organic matter, close-grained, very compact when dry, and quite slowly pervious to water. When saturated, it is soft, and posts may be driven very readily thru it. A few small quartz gravels and some concretions of hydrated iron oxid may be present in this stratum. The subsoil averages about 20 inches from the surface but varies from only a few inches on the “scalds” to 2 feet or more on the best phase of the type. It is usually made up of two distinct layers, the upper tight clay, or so-called “hardpan,” and a lower, friable, porous, silty layer. «The former *This type also contains many small unproductive areas known as “scalds” or “scald spots” readily recognized in a plowed field by their light color. Occasionally one of these spots may cover several acres but ordinarily these areas are only a few square rods. On these spots the ordinary surface soil, and, in many cases, the subsurface soil, is almost absent, thus bringing the subsoil to or very near the surface which constitutes the “scald" These spots are very irregular in their occurrence, some fields being entirely free from them, while in others there may be several or many. Bracted plantain (sometimes less properly called buckhorn) of stunted growth is a common plant upon these “scalds”. I9ii] Clay County 23 varies from 2 or 3 to more than 12 inches in thickness and is usually a tight, silty clay, reddish or yellowish in color, very sticky and gummy when wet and very hard when dry. As a rule, the drainage of this type is rather poor, due to one or both of two causes, (1) the lay of the land, and (2) the tight clay subsoil. It is still a question whether it can be tile-drained profitably; but experiments now in progress will ultimately answer the question. Usually the surplus water can be disposed of fairly well by giving proper attention to surface drainage, by means of ditches and furrows. For the economical and permanent improvement of this soil, adopt a good rotation of crops, including about one-third legume crops, plow under everything except the grain and seed (in grain farming) or make and use as much manure as possible (in live-stock farming), and apply about 1000 pounds of limestone and 200 pounds of raw phosphate, per acre, for each year in the rotation, as explained above. (Heavier initial application should be made if possible.) Brozvn-Gray Silt Loam on Tight Clay {328) This type occupies only small areas, totaling 960 acres in this county, but forms the prevailing type in the transitional area between the middle and lower Illinoisan glaciation. However, small isolated areas are found in the heart of the lower Illinoisan glaciation. With few exceptions the topography is flat or only slightly undulating. This type contains “scalds,” where the subsoil comes to the surface or injuriously near it. These are very irregular in their occurrence, some fields being devoid of them, while in others they are numerous. The surface soil, o to 6 2 /s inches, is a dark gray to brown silt loam, varying in color with its gradation toward other types. It contains about 2.8 percent of organic matter and has a small amount of clay and some fine sand, but medium and coarse silt predominates. It is porous, friable and easy to work. The subsurface stratum varies much as to thickness and color. The average thickness is 10 to 12 inches altho it may be entirely absent in some places and in others 18 inches or more in thickness. It consists of a grayish brown silt loam, the color becoming lighter with depth. There is usually a distinct gray or grayish brown layer just above the subsoil, which varies in thickness from 2 to 10 inches. Where the type grades into the gray silt loam on tight clay (330) this layer may become quite well de- veloped and partake somewhat of the impervious character of the corres- ponding layer in that type. The subsoil is found at variable depths from only a very few inches on the “scalds” to 2 feet or more on the better phase of this type. It con- sists of two distinct layers, the upper, a plastic, gummy, yellow, drab, or dark olive-colored clay, very tight and nearly impervious to water. This stratum is from 3 to 18 inches thick and below it is a clayey silt, friable and pervious, of a yellow color or yellow with drab mottlings. The upper layer of the subsoil is too impervious to allow good under- drainage, so that special surface drainage is commonly provided. The discussion of tile drainage for the gray silt loam on tight day (330) applies as well to this tvpe. In general the same system of improvement should be adopted as for 24 Soil Report No. i [March, the gray silt loam on tight clay, altho the brown-gray silt loam contains somewhat more nitrogen and phosphorus in the surface soil and less acidity in the subsoil. However, the difference in the plowed soil of an acre amounts to only about 20 loads of manure and 1 ton of phosphate, and the nitrogen is in the less active form of old humus. Drab Silt Loam (329) Some of the low and more poorly surface-drained areas of the prairie land have received deposits of finer material \yashed in from the slightly higher surrounding land, and a greater accumulation of organic matter has taken place, more particularly in the subsurface and subsoil, owing to the more luxuriant growth of vegetation and the better conditions for pre- venting complete decay. This has given rise to a type of soil, the drab silt loam (329) which is darker in color, better in texture, and somewhat more productive than the surrounding gray silt loam on tight clay (330), the ordinary prairie of this glaciation. The drab silt loam (329) needs un- der-drainage to bring it to its best condition of tilth and productiveness; and the physical composition, texture, and structure indicate that tile drain- age will greatly benefit this soil, but actual field experiments are necessary to determine how satisfactorily tile will work. With the limited appropria- tion hitherto provided for the investigation of Illinois soils, it has not been possible for the University to establish an experiment field upon this soil type which is of very considerable importance, not only because of the 14,- 400 acres of this type in Clay County, but also because of its presence in most other counties in the lower Illinoisan glaciation. The surface stratum of the drab silt loam (329) is a dark drab to brown silt loam, the former color predominating. The physical composi- tion and texture of this soil indicate that it will work up well when thoroly drained. The subsurface varies from a dark gray to a drab silt loam, frequently with blotches of yellow iron oxid. The amount of clay varies consider- ably, the stratum being very silty in some areas while in others it has suf- ficient clay to make it plastic, but in either case i^ pervious to water. The subsoil varies in color from drab to yellowish gray with sometimes irregular blotches of all mixed together, while in physical composition it varies from a friable silt to a clay. The subsoil is rather heavy yet it is sufficiently pervious so that tile drains will very probably work well, and there are very few areas of this type that would not be greatly benefited by efficient under-drainage. The variations of this type are due to gradations toward other types. Where it is grading toward the gray silt loam on tight clay (330) or the light gray silt loam on tight clay (332), the soil becomes lighter in color and the subsurface more silty, while the subsoil becomes lighter and less pervious to water. If the type is grading toward brown silt loam it be- comes darker and slightly heavier. When drained and properly treated it promises to become one of the best types in southern Illinois,* because of the absence of the gray layer and tight clay stratum in the subsurface and subsoil. From the standpoint of fertility and methods of improvement the drab silt loam does not differ essentially from the more common gray silt loam prairie land; but with equal provisions for drainage and plant food the Clay County 25 1911] drab silt loam will be a more productive soil, especially in very wet or very dry seasons, because of its more pervious character and consequent greater power to handle moisture, not only by permitting the downward flow when saturated and the upward capillary rise from the lower subsoil in time of drouth, but also because of its greater capacity for absorbing and retaining moisture; and of course it also furnishes a greater feeding range for plant roots than the less porous types. Brown Silt Loam on Clay (326.1) The areas of this type occur in about the same location as those of the drab silt loam (329), but have received more wash from adjoining higher land. It contains more organic matter in the subsurface and subsoil than any other upland type in the county. It is a good soil physically but, like the drab silt loam, needs under-drainage. The total area in the county is only 824 acres. The surface soil is a dark brown to black silt (or clayey silt) loam, rather plastic when wet, but somewhat granular under proper conditions for granulation. The subsurface stratum differs from the surface in having a slightly lighter color and containing more clay, there being sufficient to render it quite plastic. The subsoil is a brownish or dark drab silty clay somewhat impervious but probably susceptible of satisfactory drainage. While tile will probably not draw as far in this type or in the drab silt loam (329) as in some corn belt types, yet by putting the lines of tile from four to eight rods apart this land could all be well drained, so far as can be judged from physical char- acteristics. The nitrogen content of the subsurface and subsoil is naturally higher because it is one of the constituents of the organic matter, but such organic nitrogen, particularly in those strata, becomes available too slowly to be a factor of great significance; and, like the other types already described, the essential requirements for the improvement of this soil are limestone, phos- phorus, and nitrogenous organic matter. Deep Gray Silt Loam ( 331 ) This type occurs in low, poorly drained areas that have received a con- siderable amount of material washed from the surrounding higher lands, but the material deposited contains less clay than that received by the previously described types of similar topography. The surface soil is a gray to dark gray silt loam, under which to a depth of 40 inches is a gray silt loam or gray silt that differs from the surface chiefly in having a lighter color. Locally a stratum of clayey silt may be developed at about 36 inches in depth. This soil will certainly underdrain, and when drained will become very productive with proper treatment. As will be seen from Tables 3, 4, and 5, this type averages about as high in acidity and rather lower in plant food than any of the other prairie types. The greater porosity and deeper feeding range for plants are distinct advan- tages; but the same systems of improvement should be followed. 26 Soil Report No. [March, (b) Timber Uplands Light Gray Silt Loam on Tight Clay ( S3 2 ) This type occurs in old timbered regions where the land ia so nearly level that there is no chance for rapid surface drainage. The type was originally the same as the gray, silt loam on tight clay (330) but has a lower organic matter content because of the long-continued growth of timber. The upland soils that were timbered for centuries have less organic matter and are con- sequently much lighter in color than the adjoining prairie because of the fact that forest trees add very little organic matter to the soil whereas the process of decomposition is going on more or less rapidly in all soils. The leaves and twigs of the trees fall upon the surface of the ground and decay completely; whereas the prairie grasses form a mass of roots in the soil which, when they die, are prevented from complete decay by the absence of sufficient oxygen. In this way prairie grasses and other plants cause a grad- ual accumulation of organic matter. If prairie land becomes forested the organic matter is slowly diminished to a low point. The average amount of organic matter in the upland timber soils of the state is 2 percent while the prairie soils have 5.3 percent, the corn belt -soils being included in both cases. Some of the level timber soils are so depleted in this constituent; that they do not have over 1 percent in the surface stratum. This type has two distinct phases, one a slightly better surface-drained but lighter colored, and less productive, and the other the more swampy areas (where water oaks commonly grew), a darker surface and more porous soil, so that better dramage is probably possible. The amount of this latter phase is small as compared with the former and is frequently confined to narrow strips too small to map. “Scalds” are found upon this type but are not so common as upon the gray silt loam on tight clay (330) or brown gray silt loam on tight clay (328). The surface soil of the most common level timber land (332) of this glaciation is a light gray to almost white silt loam containing about 1 y 2 per- cent of organic matter. It is somewhat porous and incoherent but contains sufficient clay to bake when puddled and dried. When the moisture content is at its optimum it works very well, but because of the low organic matter content it is “run together” badly by rains or by freezing and thawing when wet. This layer as well as the subsurface and subsoil contains large numbers of iron oxid concretions of various sizes up to one-fourth inch in diameter. Small pebbles of quartz are sometimes found, possibly having been brought to the surface from the underlying glacial till by burrowing animals during past centuries. The subsurface varies from a light gray silt loam to a white silt, compact but friable, from 2 to 20 inches in thickness. Water passes thru it slowly. The subsoil consists of a compact yellowish gray clayey silt or silty clay, only slowly pervious to water, but usually not quite so tight as the correspond- ing layer of the gray silt loam on tight clay (330). In places the type has a somewhat more friable subsoil and is not so impervious as the above, and where the tight clay occurs at the greater depths from the surface it is less objectionable. The invoice of plant food shews great need, of nitrogen and phosphorus, and, with these and a liberal use of limestone and organic matter, the soil can be made highly productive with proper surface drainage. Clay County 27 J911] White Silt Loam on Tight Clay (3s 2 - 1 ) This type is found on the level upland and is or has been covered by a growth of stunted trees principally the so-called post oak. The term post- oak flat or post-oak soil is commonly applied to this type altho these terms are often applied locally to the poorer phase of light gray silt loam on tight clay (332). The surface drainage is very poor and the subsoil is almost im- pervious. The total mapped area in the county, is only 224 acres, but there are many small areas of this type that cannot be shown on the map, and much of the light-gray Silt loam on tight clay (332) grades toward this related type (332.1). Where the type has been cultivated, the surface soil is a white silt, while in the timbered areas there may be an inch or two of dark gray silt loam underlain by the characteristic white silt. The organic matter content is even lower than in the preceding type. Because of this and the high silt content, the soil “runs together” badly. Iron oxid concretions are always present. The subsurface layer is a white silt with many iron oxid concretions. The thickness varies from 4 to 16 inches, passing abruptly into the subsoil which is a light yellow, iron-stained silty clay, very tough and plastic when wet and hard when dry. Both subsurface and subsoil are almost impervious and when these layers are dry water moves down into them with extreme slowness. In nitrogen and phosphorus this is one of the poorest soils found in the state, the total in the surface soil 6 % inches deep being about equal to the needs of three rotations in nitrogen and of five rotations in phosphorus, with such crops as are suggested in Table 1 ; and with no provision to make plant food available the crops produced on this type are often not worth raising. With liberal use of limestone, phosphorus, and organic matter this soil can be markedly and profitably improved where the surface drainage is adequate ; but, like all soils with tight clay subsoils, it will not be a good soil for very wet or very dry seasons. Yellow-Gray Silt Loam (334) This type lies between the yellow silt loam (335), on the one hand, and the gray silt loam on tight clay (330) or light gray silt loam on tight clay (33 2 )> on the other, and it is somewhat intermediate, in character. For gen- eral agricultural purposes it is one of the best types of soil in the county, provided it exists in large areas; whereas small areas are sometimes almost valueless because of scald spots. The common topography is undulating but varies from nearly level to almost broken land. The slopes are rather long and gentle, but in places very short abrupt slopes of yellow silt loam occur which are too small in area to show separately on the . map. The surface drainage is generally good, in fact so good that there is considerable washing going on where the methods of culture are not the best for preventing it. While this type was generally timbered, it sometimes extends out into the prairie along natural drainage channels and as these particular areas represent recent erosion of the prairie, it shows “scalds” or tight clay outcrops, the presence of which renders these narrow areas very inferior to the type generally, and in some places almost worthless. These numerous “scald” areas are rarely over two or three acres 28 Soil Report No. i [March, in extent and more frequently only a fraction of an acre, often occurring as narrow strips along the stream or draw. The total area of yellow-gray silt loam is 21,240 acres, or 7.09 percent of the total area of the county. Since the type is a transitional form, between other types, the surface soil varies a great deal. The predominating phase is a yellowish or grayish yellow silt loam, but the type varies from that to a gray silt loam as it grades toward the gray and the light gray silt loam on tight clay (330 or 332), or to yellow silt loam as it passes into the eroded type (335). In physical composition, it contains some fine sand and locally, in small areas, quite appreciable amounts, but the prominent constituent is silt of various grades. The soil is deficient in organic matter, there being only 1^2 to 2 percent present. The surface soil is porous and friable but “runs to- gether’’ badly because of its shortage in organic matter. The subsurface, like the surface, varies from a yellowish gray to yellow silt loam sufficiently porous to permit percolation, and the physical composi- tion is such as to allow ready capillary movement. The thickness of the subsurface stratum varies from a few inches to about 16 inches. The subsoil is a yellow or mottled grayish silt or clayey silt, somewhat compact but pervious. The depth to the subsoil is quite variable owing to the amount of washing that has taken place. In places the surface and sub- surface have been entirely removed, but this is unusual, and the depth to the subsoil varies commonly from 10 to 20 inches. With good farming and a liberal use of limestone, phosphorus, and le- gumes, this soil can be profitably improved until it will produce larger crops than the present average of the $200 corn belt land, which, of course, will just as certainly lose its high productive power if the common agricultural practice of the corn belt is continued, with no adequate return to the soil for the large amounts of plant food removed in crops. Yellow Silt Loam (335) This type includes the broken, very rolling, and hilly land along the streams and sometimes on the steep slopes of ridges. It is of such a steeply sloping character that much of it should never have been put under cultiva- tion. When properly treated it makes excellent pasture land, and much of it should be kept forested. When cultivated the utmost care should be taken to prevent washing as this is the most serious danger to this type of soil. Already many fields have been ruined by gullying. In Clay County it covers an area of 41,760 acres, or 14 percent of the total. The surface soil is a friable yellow silt loam varying somewhat with topography, the less broken being grayish yellow while the steep slopes are reddish yellow, or brownish yellow where a little more organic matter re- mains. As a rule, the soil has enough fine sand for fairly good texture, but it is very deficient in organic matter and this condition "contributes toward its excessive washing. “Clay points”, or places where the top soil has been removed by washing, are quite common and they are very unproductive. The subsurface varies but is from 6 to 14 inches thick where little or no washing has taken place. It consists usually of a friable yellow slightly loamy silt mottled with gray or with reddish blotches of iron oxid. The subsoil is usually a somewhat friable and quite pervious yellow clayey silt. Where much washing has occurred the glacial drift frequently forms the subsoil. Clay County 29 1911] Where soil improvement is attempted, large use should be made of lime- stone and legumes. Limestone may be applied as a top-dressing even on permanent pastures, and some clover can usually be introduced into the pasture herbage by mixing the clover seed with much limestone and some dry soil containing clover bacteria, and sowing with a sharp disk drill with fertilizer attachment, thus placing the inoculated clover seed in the soil itself and in contact with the limestone. As a rule it is not advisable to apply phos^ phorus to this soil except where ample provision is made for increasing the organic matter and nitrogen and for preventing loss by erosion ; and the phosphorus should not be used as a top-dressing, but thoroly mixed with the plowed soil before seeding down to grass and clover. (c) Ridge Soils Yellow Silt Loam (235) The morainal and preglacial ridges of the lower Illinoisan glaciation have given a slight variation to the usual level topography of this region. These have been covered with from 8 to 15 feet of loess and this, together with the excellent drainage, has resulted in the formation of a soil very different from the surrounding prairie but somewhat resembling in texture the better phase of the yellow silt loam timber land (335), already described. The total area of the type is 2560 acres. The ridges upon which this type occurs vary from 20 feet to 100 feet or more in height. The surface soil is a yellow or yellowish-brown silt loam with consider- able very fine sand. The color varies with the amount of erosion that has gone on. Where little washing has occurred the color may be a yellowish brown, while with more washing it will become yellow. The soil is loose, porous, readily pervious to water and its physical composition is such as to give it great water-retaining power and strong capillarity so that it will re- sist drouth well. The organic matter content is about 3^ percent. The subsurface layer, 6 2 / 3 to 20 inches, varies from a yellowish brown silt loam to a yellow silt or slightly clayey silt. It becomes more compact with depth but still retains its perviousness and capillary power. The upper part of the subsoil is somewhat compact and slightly clayey but passes into a friable silt containing some fine sand. It is yellow or red- dish-yellow in color. Below 24 inches it may be slightly gray or marked with gray blotches, and when grading toward yellow-gray silt loam (334) may become decidedly gray. This soil, considered from a physical standpoint, is about as good as could be desired. Its organic matter content should be maintained and even increased in order to prevent destructive washing. It is a well-aerated, well-drained soil and will withstand drouth well, and in those respects it is decidedly the best upland type in the county. It also contains a fair amount of plant food, exceeding in its nitrogen content all other upland types and even the extensive bottom lands Never- theless it is plain to see that nitrogen and phosphorus are the limiting ele- ments in this as well as in most other soils of the county ; and with the well developed acidity of the subsurface and subsoil, the essential require- ments for its improvement are the same; namely, a liberal use of limestone phosphorus, and legume crops in a good rotation, the legumes and at least the coarse product of the other crops being returned to the soil either directly 30 Soil Report No. [March, or in manure. By these means this soil can readily be made to produce crop yields equal to those of the best soils in the state. It is especially well adapted for alfalfa when well treated with limestone and manured and in- oculated to give the alfalfa a good start. Gray-red Silt Loam on Tight Clay (233) This type of soil occurs on the low ridges, which are in part at least of preglacial origin, varying from 5 to 75 feet above the surrounding upland. As a rule, it is one of the poorest upland types in the state, but the areas in this county are usually a better phase of the tyfie. It comprises 9180 acres, or 3 percent of the area of the county. The surface drainage is usually good, and in some places the type may suffer from erosion; but it is extremely doubtful whether tile-drainage will profitably benefit this soil, at best not until other methods of improvement have been put into practice. The surface soil is a friable gray silt loam very similar to that of the gray silt loam on tight clay (330), and the subsurface layer resembles the corresponding one in the above type both in texture and thickness but con- tains more of the higher oxid of iron, giving it a reddish color. The subsoil varies in depth from 7 to 20 inches from the surface and consists of a layer of plastic, gummy, impervious red clay varying from 4 to 12 inches thick and underlain by a less plastic and more silty stratum. When dry the red clay becomes so hard that it is next to impossible to bore into it with an auger. Where this layer becomes the surface soil, which it does on some small eroded areas, the soil is practically worthless. In plant food content this soil is almost a perfect duplicate of the gray silt loam on tight clay, not only in the surface, but likewise in the sub- surface and subsoil ; but with its tighter texture and more rolling topog- raphy, more erosion and less leaching have occurred, and consequently it has retained more acidity and somewhat more of the abundant mineral ele- ments. Methods for improvement are, of course, the same as for the more extensive gray silt loam on tight clay. (d) Bottom Lands Deep Gray Silt Loam ( 1331 ) This type occurs along most of the streams of the lower Illinoisan glacia- tion. The material from which it is formed comes from the gray, yellow- grav, and yellow silt loams of the upland, and has a gray or yellowish gray color. It overflows during floods and in most places still receives frequent or occasional deposits of new material. If we disregard the difficulties from overflow and of drainage, this is the most valuable important soil type in the county. There is in the county a total area of 31,680 acres of this type. It lies so low that the drainage is generally poor and there is often much difficulty in getting sufficient outlet for under-drainage or sometimes even for adequate surface drainage. Where a satisfactory outlet can be secured tile drainage greatly benefits this soil. The surface soil is a gray silt loam varying from a light drab to drab in color and from a loam to a clayey silt loam in physical composition. The subsurface and subsoil are about the same as the surface except lighter in Clay County 31 1911] color and commonly a little more clayey with depth. In the smaller stream bottoms the recent deposits are frequently yellow and consequently there may be a stratum of yellow on the gray varying from a few inches to a foot or more in thickness. In phosphorus content this soil slightly exceeds the most common prairie soil of the corn belt, and the porous subsoil affords such a deep feeding range that the application of that element is not likely to give profitable re- turns, except where overflow is not common and where the soil has been long cropped. The soil is moderately acid and rather poor in nitrogen, altho this per- centage deficiency is counterbalanced to a large extent by its 'great depth and porosity. While the overflow and drainage problems are of first importance, where these are under sufficient control to permit of soil improvement the use of limestone and the addition of nitrogenous organic matter, as by plowing un- der clover or manure, will make this soil still more productive ; and, if pro- tected so as to prevent the usual overflow deposits, the addition of phos- phorus will ultimately be necessary, and is likely to be very profitable for the highest improvement of the soil. To illustrate it may be pointed out that on the University farm at Urbana, land which has yielded 65 bushels of corn per acre as a six-year average, in a rotation of corn, oats, and clover, where limestone and organic manures have been provided, has with the addi- tion of phosphorus made an average of 87 bushels during- the same years. Thus there may be room for phosphorus “at the top”, even where very sat- isfactory yields may be secured without its application and where other factors are of first importance. Mixed Sandy Loam (ijdi) This type occurs chiefly in the bottom lands of the smaller streams and principally in the northwest part of the county, where its greater prevalence is probably due to the presence in that section of a deposit of sandstone which frequently outcrops along- the streams. The breaking down of this sandstone, together with the small amount washed in from the upland, fur- nishes sufficient sand to form the type. Practically all of it is subject to overflow. It varies greatly in physical composition which in places is changed more or less with each flood. The surface soil is a brown, yellowish brown, or yellowish gray sandy loam. It is very pervious to water but usually has enough of the finer soil constituents to make it sufficiently retentive of moisture to grow good crops. All grades of sand are present but the coarse and medium predominate. In small areas it varies in physical composition from loam to sand. The or- ganic matter content also varies, but averages about 2p£ percent. The subsurface is a sandy loam, lighter in color than the surface, often becoming more sandy with depth and usually passing into a coarse yellow or yellowish gray sand subsoil. The content of sand and the depth to the sand subsoil varies with the topography, the higher places being more sandy, while the low areas are more silty and more variable in the subsoil. The soil is very productive ex- cept on very sandy spots, which are sometimes present but not large enough to map. Because of their open character sand soils are aerated to much greater depths than soils in which silt or clay predominate and because of this a much 32 Soil Report No. i [March, ign larger amount of plant food is made available even though the sand soil may be no richer in the important elements. Thus with the same content of nitro- gen and phosphorus as the gray silt loam prairie, the sand soil will produce twice as large crops, because the aeration and feeding range is at least twice as great. The acidity of the sand soil is slight. Where it is subject to fre- quent overflow it is doubtful if any applications will prove profitable, but where overflow is not common both limestome and manure may well be used in preparing the soil for alfalfa for which it is well adapted if the drainage is good. Drab Clay (1315) The total area of this type in the county comprises 25 acres situated in the bottom land near the Little Wabash River in an area adjoining the deep peat (1301). It is a common type in old bayous along the Mississippi, Kas- kaskia, and Wabash Rivers, occurring in the low, poorly drained areas, chiefly former stream channels, now partly filled with the finest sediment. The surface soil is a dark drab, granular, plastic clay. The subsurface and subsoil are lighter in color than the surface but also consists of plastic clay. The type is difficult to work, especially if not well drained, the common condition. It is a neutral soil and fairly well supplied with plant food. The one area found in the county is only a few inches above the usual level of the ground water. It has never been cropped and probably never will be unless it is included in some future extensive drainage district in which the general level of the Little Wabash River should be lowered so as to provide an outlet for such low-lying bottom lands. Deep Peat ( 1301 ) This type is found in a single small area of only 15 acres where springs abound (Section 3, Township 3, Range 8), and the type represents the accumulation of vegetation formed by the growth of grasses, sedges, mosses and other plants. The surface of the peat is only a few inches above the water level, and as an outlet for adequate drainage could be provided only at great expense (or in connection with an extensive drainage system), the utilization of this area for anything but pasture is quite impracticable at present. The samples show considerable carbonate present, principally as fragments of shells. This soil contains about 50 percent of organic matter and more than 20 * percent of limestone. If it could be obtained in dry condition so as to reduce the expense of hauling, it could be used with some profit as a fertilizer on the acid upland soils in the neighborhood, which, as a rule, are also markedly deficient in nitrogen and organic matter. The addition of a small applica- tion of manure or some clover turned under would hasten the decomposition of the peaty material and thus greatly increase its value when used as a fer- tilizer. (It should be noted that the specific gravity of peat soil is only about one-half that of normal soil; and consequently an acre of peat soil 6^3 inches deep weighs, in the dry condition, 1 million pounds, while ordi- nary soils weigh 2 million pounds for the same stratum.) UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 2 MOULTRIE COUNTY SOILS] By CYRIB G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and J. E. READHIMER URBANA, ILLINOIS, JUNE, 1911 State Advisory Committee on Soil Investigations Ralph Allen, Delavah F. I. Mann, Gilman A. N. Abbott, Morrison J. P. Mason, Elgin E. W. Burroughs, Edwardsville Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief in Agronomy and Chemistry Soil Survey — J. G. Mosier, Assistant Chief A. F. Gustafson, Assistant C. C. Logan, Assistant S. V. Holt, Assistant H. W. Stewart, Assistant H. C. Wheeler, Assistant Soil Analysis — J. H. Pettit, Assistant Chief E. VanAlstirie, Assistant J. P. Aumer, Assistant Gertrude Niederman, Assistant 1 W. H. Sachs, Assistant Frances D. Abbott, Assistant W. R. Leighty, Assistant Soil Experiment Fields — J. E. Readhimer, Superintendent Wm. G. Eckhardt, Assistant O. S. Fisher, Assistant J. E. Whitchurch, Assistant E. E. Hoskins, Assistant MOULTRIE COUNTY SOILS By CYRIL, G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and J. E. READHIMER Introduction About two-thiras of Illinois lies in the corn belt, where most of the prairie lands are black or dark brown in color. In the southern third of the state the prairie soils are largely of a gray color, and this region is better known as the wheat belt, altho wheat is often grown in the corn belt and corn is also a common crop in the wheat belt. Moultrie County, representing the corn belt ; Clay County, which is fairly representative of the wheat belt ; and Hardin County, which is taken to represent the unglaciated area of the extreme southern part of the State, have been selected for the first Illinois Soil Reports by counties. While subsequent County Soil Reports will be sent only to the residents of the county concerned (and to anyone else upon request), these first three are sent to the Station’s entire mailing list within the State. Each county report is intended to be as nearly complete in itself as it is practicable to make it, and even at the expense of some repetition, each will contain a general discussion of important fundamental principles to help the farmer and landowner to understand the meaning of the soil fer- tility invoice for the lands in which he is interested. In Soil Report No. I, “Clay County Soils,” this discussion serves in part as an introduction, while in this and other reports it will be found in the Appendix, but if necessar” it should be read and studied in advance of the re-port proper. Soil Formation Moultrie County lies wholly within the Early Wisconsin Glaciation, but near its southern border. While it has no very distinct morainal ridges, yet the county is covered to an average depth of more than 200 feet with a deposit of glacial drift consisting generally of a mixture of clay, silt, sand, gravel, and boulders. This drift consists of the Illinoisan below and the Wisconsin above, separated by the Iowan loess carrying the old Sanga- mon soil. Covering the Wisconsin drift to a depth of three to six feet or more is another layer of fine-grained, loessial or wind-blown material from which the present soil has been formed. This has been modified to a con- siderable degree by different conditions and agencies, such as the growth of grasses, of timber, washing and drainage, which have given rise to the different soil types found in the county. 3 4 Soil Report No. 2 [June, Table 1.— Soil Types of Moultrie County Soil Type No. Names Area in sq. mi. Area in acres Percent of total 1126 (a) Upland Prairie Soils (Page 20) Brown silt loam 264.42 169,229 77.52 1120 Black clay loam 15.42 9,869 4.52 1132 (b) Upland Timber Soils (Page 23) Light gray silt loam on tight clay 4.75 3,040 1.39 1134 Y ellow-gray silt loam '35.05 22,432 10 28 1135 Yellow silt loam 2.19 1,402 .64 1454 (c) Swamp and Bottom-land Soils (Page 25) Mixed loam 13.72 8,781 4.02 1554.6 (d) Terrace Soil (Page 26) Mixed loam over sand or gravel 5.51 3,526 1.61 Totals 341.06 218,279 100.00 The only soil type in the county which includes non-tillable land is the yellow silt loam, whose topography is often so steeply sloping that it ought to be kept in forest or at least almost continuously in pasture. Of course, much of the swamp and bottom land needs more adequate drainage, which is very difficult, if not impracticable, to provide as yet in some places. THE INVOICE AND INCREASE OF FERTILITY IN MOULTRIE COUNTY SOILS Soil Analysis In order to avoid complication and confusion in the practical application of the technical information contained in this report, the results are given in the most simplified form. The composition reported for a given soil type is as a rule the average of many analyses, which, like most things in nature, show more or less variation. For all practical purposes the average is most trustworthy and sufficient, as will be seen from Bulletin 123, which reports the general soil survey of the state, and in which are reported many hundred individual analyses of soil samples representing twenty-five of the most important and most extensive soil types in the state. The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but the rate of liberation is governed by many factors, as explained in the Appendix. As there stated, probably no agricultural fact is more generally known by farmers and land- owners than that soils differ in productive power. Even though plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that the produc- tive power of normal soil in humid sections depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated. i-iOz AAMILOD moovk AXMIIOO MODVJNT AX Ml 1 1 K£2z COUES COUNTY 9 VM SOIL SURVEY MAP OF MOULTRIE COUNTY UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Moultrie County 5 1911} The fact may be repeated, too, that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agri- cultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, and seven from the soil, altho nitrogen, one of these seven elements secured from the soil by all plants may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches among our common agricultural plants) secure only from the soil six elements (phosphorus, potassium, magnesium, calcium, iron and sulfur) and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Table A, in the Appendix, shows the requirements of large crops for the five most important plant food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance, compared with- the amounts needed by plants, so tha-t they are not known ever to limit the yield of crops.) In Table 2 is recorded the invoice of the plowed soil, showing the total amounts of these five elements of plant food contained in each of the dif- ferent types of soil in Moultrie County. Table 2 Fertility in the Soils oe Moultrie County, Illinois Average pounds per acre in 2 million pounds of surface soil (about 0 to 6% inches) Soil Total Total Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- calci- stone stone No. carbon gen phorus sium sium um present required Upland Prairie Soils 1126 Brown silt loam 52260 4810 980 36020 8650 10430 8T 1120 Black clay loam (normal phase) . 72280 6480 1810 35260 14830 20460 8350 1120 Black clay loam (lighter phase) . 52600 6940 1320 32120 15080 18560 760 Upland Timber Soils 1132 Light gray silt loam on tight clay 19810 1680 600 35080 6350 7390 120 1134 Yellow gray silt loam 28170 2310 680 36150 6040 6370 180 1135 Yellow silt loam 19260 1580 480 36960 6220 5180 320 Swamp and Bottom-land Soils 1454 Mixed loam (normal phase) 41940 4180 1260 41740 9820 13000 780 1454 Mixed loam (lighter phase) 24420 2600 620 37040 8520 13000 7780 Terrace Soil Mixed loam over sand or gravel .... 11940 1300 500 34860 5460 6300 These data represent the total amounts of plant food found in two million pounds of the surface soil, which corresponds to an acre of soil about 6% inches deep, including at least as much soil as is ordinarily turned with 6 Soil Report No. 2 [June, the plow, and representing that part of the soil with which we incorporate the farm manure, limestone, phosphate, or other fertilizer applied in soil improvement. This is the soil stratum upon which we must depend in large part to furnish the necessary plant food for the production of the crops grown, as will be seen from the information given in the Appendix. Even a rich subsoil has little or no value if it lies beneath a worn-out surface, but if the fertility of the surface soil is maintained at a high point then the strong and vigorous plants will have power to secure more plant food from the subsurface and subsoil than would be the case with weak, shallow- rooted plants. By easy computation it will be found that the most common prairie soil of Moultrie County does not contain enough total nitrogen in the plowed soil for the production of maximum crops for ten rotations; while the up- land timber soils contain as an average less than one half as much nitrogen as the prairie land. Practically the same condition obtains with respect to phosphorus, nine- tenths of the soil area of the county containing no more of that element than would be required for twelve crop rotations if such crop yields were secured as suggested in Table A of the Appendix; and in case of the cereals it will be seen that about three-fourths of the phosphorus taken from the soil is deposited in the grain, while only one-fourth remains in the straw or stalks. On the other hand, the potassium is sufficient for 2,800 years, if only the grain is sold, or for 450 years even if total crops were removed and nothing returned. The corresponding figures are about 2,100 and 500 years for magnesium, and about 10,000 and 250 years for calcium. Thus, when measured by the actual crop requirements for plant food, potassium is no more limited than magnesium and calcium and, as explained in the Appendix, with these elements we must also consider the heavier loss by leaching. These general statements relating to the total quantities of plant food in the plowed soil certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the needs of large crop yields for even one or two generations of people. The variation among the different soil types with respect to their content of important plant food elements is also very marked. Thus, the prairie soils contain from three to four times as much nitrogen as the timber lands of the same topography ; and the normal black clay loam, the richest prairie land, contains about three times as much phosphorus as the upland timber soils. On the other hand, the most significant fact revealed by the investiga- tion of Moultrie County soils is the low phosphorus content of the common brown silt loam prairie, a type of soil which covers more than three-fourths of the entire county. The market value of this land is about $200 an acre, and yet an application of $30 worth of fine-ground raw rock phosphate would double the phosphorus content of the plowed soil. Such an applica- tion properly made would also double the yield of clover in the near future ; and, if the clover were then returned to the soil either directly or in farm manure, the combined effect of the phosphorus and nitrogenous organic matter with' a good rotation of crops would soon double the yield of com on most farms. Moultrie County 7 jp/j] The average yield of corn of Moultrie County for the ten years, 1901 to 1910, is 34.7 bushels per acre;* yet this county occupies the most favored position in the most southern lobe of the corn belt of the United States. Meanwhile, Boone County, or the Wisconsin line, nearly 200 miles farther north, has averaged 40.5 bushels of corn per acre during the same ten years. With nearly 5,000 pounds of nitrogen in the soil and an inexhaustible supply in the air, with 36,000 pounds of potassium in the same soil and with practically no acidity, the economic loss of farming such land with less than 1,000 pounds of total phosphorus in the plowed soil can only be ap- preciated by the man who fully realizes that the crop yields could be doubled by adding phosphorus, — and without change of seed or season and with very little more work than is now devoted to the fields. Fortunately, some definite field experiments have already been conducted on this same type of soil in different counties in the same soil area as Moultrie (the Early Wisconsin Glaciation), as at Urbana in Champaign County, at Sibley in Ford County, and at Bloomington in McLean County. Results of Field Experiments at Urbana A three-year rotation of corn, oats, and clover was begun on the North Farm at the University of Illinois in 1902, on three fields of typical brown silt loam prairie land which, after twenty years or more of pasturing, had grown corn in 1895, 1896 and 1897 (when careful records were kept of the yields produced), and had then been cropped with clover and grass on one field, oats on another, and oats, cowpeas and corn on the third field, till 1901. As an average of the three years, 1902-1904, phosphorus increased the crop yields per acre by .68 ton of clover, 8.8 bushels of corn, and 1.9 bushels of oats. During the second three years, 1905-1907, phosphorus produced average increases of .79 ton of clover, 13.2 bushels of corn, and 11.9 bushels of oats. The third course of the rotation, 1908-1910, the average increases produced by phosphorus were 1.05 tons of clover, 18.7 bushels of corn, and 8.4 bushels of oats. For convenient reference the results are summarized in Table 3. Table 3. — Fffect of Phosphorus on Brown Silt Loam (Average increase per acre) Rotation Years Corn | Oats Clover tons Value of increase ' Cost of treatment* Bus: hels First 1902, 3, 4 8.8 1.9 .68 $ 7.73 $7.50 Second 1905, 6, 7 13.2 11.9 .79 12.93 7.50 Third 1908, 9, 10 18.7 8.4 1.05 15.37 7.17 *Prices used are 35 cents a bushel for corn, 30 cents for oats, $6.00 a ton for clover hay, 10 cents and 3 cents a pound for phosphorus in bone meal and rock phosphate, re- spectively. As an average the well treated land has produced about 90 bushels of corn, 60 bushels of oats, and 2^/2 tons of hay per acre. These crops would remove about 130 pounds of phosphorus in the nine years, while 300 pounds *Statistical Report, Illinois State Board of Agriculture, December 1, 1910, page '39. 8 Soil Report No. 2 [June, Plate 1. Corn on Urban a experiment field Legume crops and crop residues plowed under Limestone applied were applied (in bone meal and in rock phosphate, as explained below), so that the average phosphorus content of the plowed soil has been increased from about 1,100 in 1901 to 1,300 pounds per acre in 1910, about 30 pounds having been returned, as an average, in the organic manures described below. Meanwhile the untreated land has lost about 100 pounds of phosphorus, corresponding to a reduction from 1,100 to 1,000 pounds. As shown in Table 3, the phosphorus paid its cost the first rotation, and the third rotation it paid more than twice its cost, besides leaving the treated soil about one-third richer in phosphorus than the untreated soil. During the first six years, 1902-1907, phosphorus was applied at the rate of 25 pounds per acre per annum in 200 pounds of steamed bone meal, 600 pounds of bone usually being applied once every three years on the clover sod and plowed under for corn. For the last rotation, 1908-1910, the 600 pounds of steamed bone were applied on one-half of each plot, and 1,800 pounds of fine-ground raw rock phosphate on the other half. The bone I9IJ] Moultrie County 9 Plate 2. Corn on Urbana experiment field IfEGUME CROPS AND CROP RESIDUES PLOWED UNDER Limestone and phosphorus applied costs about $25 a ton (10 cents a pound for 250 of phosphorus), and the raw phosphate about $7.50 per ton (3 cents a pound for 250 of phosphorus). As an average of the last three years one dollar invested has paid back $2.38 from bone meal and $2.39 from raw rock phosphate in the value of the increase ; and, of course, the reserve supply of phosphorus is much greater where the rock phosphate is used. In 1910 the respective increases in yield from bone meal and rock phosphate were 15.2 and 19.6 bushels of corn, 11.9 and 12.8 bushels of oats, and 1.33 and 1.37 tons of clover hay, the larger increase being produced by the raw rock phosphate with every crop, in harmony with the cumulative effect to be expected from the increasing store of phosphorus in the soil. As a rule, each increase given in Table 3 represents the average of dupli- cate tests over a period of three years. These averages are considered! trustworthy, excepting, perhaps, some results on oats, due to abnormal seasons. Normally the oat crop shows a gradually increasing effect from the use of phosphorus. (The increase for oats in 1910 was 13.8 bushels in grain farming and 11 bushels in live-stock farming.) 10 Soil Report No. 2 [June, Plate 3. Clover on Urbana experiment field LEGUME CROPS AND CROP RESIDUES PLOWED UNDER Limestone applied The duplicate tests each year correspond to the two systems of farming adopted on these fields, one of which is a grain system in which the nitrogen and organic matter are maintained or increased by returning to the land all crop residues left after the grain or seed is sold. These residues include the corn stalks, straw, and all clover except the seed. This system in complete form has been practiced only during the last three years, 1908- 1910, and consequently corn has not yet been grown on land where the corn stalks had been returned to the soil. In the other system, known as live-stock farming, the crops are all harvested and used for feed and bedding, and as many tons of average manure are applied as the total number of tons of air-dry produce from the respective plots. This system in complete form has been followed only dur- ing the last six years, 1905- 1910. By computation from data reported in the Appendix, it can be determined that about twice as much phosphorus leaves the farm in grain farming as in live-stock farming; and, in consequence, it is to be expected that the ap- plication of phosphorus will produce greater effects in the grain-farming system than in live-stock fanning. Table 4 contains more complete data for the corn crops grown on these fields, including die average yields o. 1895-1897, before any treatment was applied. (For full entails, see Bulletin 125.) It should be noted that .10 manure was applied during the first rotation, 1902-1904; and that crop residues have been returned only during the last rotation, 1908-1910. (On plots 2, 4, 6, an' C some legume catch crops have been seeded in the corn at the time of the last cultivation, but the results have not shown any benefit where oats follow corn, because with a good growth of corn the catch crop makes but little growth the same season, and there is no opportunity for it the following spring where the land must be seeded to oats.) Moultrie County 11 1911] Plate 4 . Clover on Urbana experiment field IyEGUME CROPS AND CROP RESIDUES PLOWED UNDER Limestone and phosphorus applied Table 4 — Average Corn Yields per Acre on Urbana Experiment Field, On Common Corn Belt Prairie Soil: Brown Silt Eoam Plot No. 1 2 3 4 5 6 7 8 9 Corn, 1895-7 61.2 63 4 61.2 63.1 66.1 65.9 65.7 64.0 65.9 Plan of treat- ment partially begun, 1902 None Resi- dues Ma- nure Resi- dues, lime Ma- nure, lime Residues, lime, phos- phorus Manure, lime, phos- phorus Residues, lime, phos- phorus, potas- sium Manure, lime, phos- phorus, potas- sium Corn, 1902-4 75.4 77.4 75.3 78.4 80.8 88.0 88.8 90.1 90.5 Corn, 1905-7 71.5 68.5 80.5 72.3 84.8 90.4 93.2 93.8 95.6 Corn, 1908-10 .... 49.4 51.5 69.3 58.1 74.9 83.8 86.6 86.7 90.9 Average Increase from Treatment Named: Corn, bushels By additions Resi- dues Ma- nure Bime Eime Phos- phorus Phos- phorus Potas- sium Potas- sium 1902-4; 3 yrs 1.0 5.5 9.6 8.0 2.1 1.7 1905-7; 3 yrs 9.0 3.8 4.3 18.1 8.4 3.4 2.4 1908-10; 3 yrs 2.1 19.9 | 6.6 5.6 25. 7 11.7 2.9 4.3 Even though the grain system was not fully underway, the organic manures, limestone and phosphorus increased the yield of corn by 34.4 bushels per acre in grain farming, and by 37.2 bushels in live-stock farming, as an average of the last three years. Wheat is grown on the University South Farm, in a rotation experiment started more recently. As an average of the last three years, 1908-1910, raw rock phosphate, (with no previous applications of bone meal) has increased the yield of wheat by 8.4 bushels per acre, and here too the phosphorus has paid back more than twice its cost, as an average of the 12 Soil Report No. 2 [June, Plate 5. Wheat in 1911 on Urbana field Catch crops and crop residues plowed under Average yield, 35.2 bushels per acre last three years, the cost being $1.87^2, and the value of the increase $3.81 per acre per annum, wheat being valued at 70 cents a bushel and other crops as noted above. (Only five-sixths as muph rock phosphate is applied on the South Farm as is reported above for the third rotation in the North Farm experiments, and even this application will be reduced one-half or more after the soil has become sufficiently rich for the production of maximum crops. ) Since the above was written the 1911 crop of wheat has been harvested and threshed on the University South Farm. In the grain system of farming, the yield was 35.2 bushels per acre where catch crops and crop residues have been plowed under without the use of phosphorus ; but where rock phosphate has been used the average yield was 50.1 bushels in the same system. (See Plates 5 and 6.) In the live-stock farming, the yield was 34.2 bushels where manure and catch crops are used without phosphate, and 51.8 bushels, as an average, where rock phosphate is used in connection with the live-stock system. (See Plates 7 and 8.) Moultrie County 13 J9U\ Plate 6. Wheat in 1911 ON Urbana field Catch crops and crop residues plowed under Fine-ground rock phosphate applied Average yield, 50.1 bushels per acre These results emphasize the cumulative effect of permanent systems of soil improvement. The value of the increase produced by phosphorus in the 1911 wheat crop alone would nearly pay for the cost of the phosphate for eight years. Results oe Experiments on Sibley Field Table 5 gives results obtained during the past nine years from the Sibley soil experiment field, located in Ford County on typical brown silt loam prairie of the Illinois corn belt. Previous to 1902 this land had been cropped with corn and oats for many years under a system of tenant farming and the soil had become somewhat deficient in active humus. While phosphorus was the limiting element of plant food, the supply of nitrogen becoming available annually was but little in excess of the phosphorus, as is well shown by the com yields for 1903, when phosphorus produced an increase of 8 bushels, nitro- 14 Soil Report No. 2 [June, Plate 7. Wheat in 1911 on Urban a field Catch crops and farm manure plowed under Average yield, 34.2 jushels per acre gen without phosphorus produced no increase, but nitrogen and phosphorus increased the yield by 15 bushels. After six years of additional cropping, however, nitrogen appears to have become the most limiting element, the increase in 1907 being 9 bushels from nitrogen and only 5 bushels from phosphorus, while both together produced an increase of 33 bushels of corn. By comparing the corn yields for the four years, 1902, 1903, 1906 and 1907, it will be seen that the untreated land has apparently grown less productive, whereas on land re- •ceiving both phosphorus and nitrogen the yield has appreciably increased, so that in 1907, when the untreated rotated land produced only 34 bushels •of corn per acre, a yield of 72 bushels, or more than twice as much, was produced where lime nitrogep and phosphorus had been applied, althc these two plots produced exactly the same yield (57 bushels) in 1902. Even in the unfavorable season of 1910 the highest yielding plot ex ceeded that of 1902, while the untreated land produced less than half as much. Phosphorus appears to have been the first limiting element again in 1909 and 1910. Moultrie County 15 1911] Plate 8. Wheat in 1911 ON Urbana field Catch crops and farm manure plowed under Fine-ground rock phosphate applied Average yield, 51.8 bushels per acre In the lower part of Table 5 are shown the total values per acre of the nine crops from each of the ten different plots, the amounts varying from $140.17 to $214.96; also the value of the increase produced; first, above the untreated land; and, second, above the treatment with lime alone, com being valued at 35 c.ents a bushel, oats at 30 cents and wheat at 70 cents. Phosphorus without nitrogen produced $24.44 i n addition to the in- crease by lime; and with nitrogen phosphorus produced $56.14 in addition to the increase by lime and nitrogen, the principal part of these increases having been made during the later years. The results show that in 21 cases out of 36 the addition of potassium decreased the crop yields. By comparing plots 101 and 102, and also 109 and no, it will be seen that the average increase by lime was $9.90, or more than $1.00 an acre a year, suggesting that the time is near when limestone must be applied to these brown silt loam soils. 16 Soil Report No. 2 [June, Table 5— Crop Yields in Soil Experiments:— Sibley Field Brown silt loam prairie; Corn Corn Oats Wheat Corn Corn Oats Wheat Corn Early Wisconsin glaciation 1902 1903 1904 1905 1906 1907 1908 1909 1910 applied Bushels per acre 101 None 57.3 50.4 74.4 29.5 36.7 33.9 25.9 25.3 26.6 lu2 Lime 60.0 54.0 74.7 31.7 39.2 38.9 24.7 28.8 34.0 103 Lime, nitrogen 60.0 54.3 77.5 32.8 41.7 48 1 36.3 19.0 29.0 104 Lime, phosphorus.. 61.3 62.3 92.5 36.3 44.8 43.5 25.6 32.2 52.0 105 Lime, potassium. . 56.0 49.9 74.4 30.2 37.5 34.9 22.2 23.2 34.2 106 Lime, nitrogen phosphorus. . . . 57.3 69.1 88.4 45.2 68.5 72.3 45.6 33.3 55.6 107 Lime, nitrogen potassium .... 53.3 51.4 75.9 37.7 39.7 51.1 42.2 25.8 46.2 108 Lime, phosphorus potassium 58.7 60.9 80.0 39.8 41.5 39.8 27.2 28.5 43.0 109 Lime, nitrogen, phosphorus, potassium 58.7 65.9 82.5 48.0 69.5 80.1 52.8 35.0 58.0 110 Nitrogen, phosphorus, potassium 60.0 60.1 85.0 48.5 63.3 72.3 44.1 30.8 64.4 Value of Crops per Acre in Nine Years Plot Soil treatment applied Total value of nine crops Value of increase 101 102 None Lime $140.17 151.30 $11.13 Over lime 103 Lime, nitrogen 151.99 11.82 $ .69 104 Lime, phosphorus . . . 175.74 35.57 24.44 105 Lime, potassium . . . 140.73 .56 (-10.57) 106 Lime, nitrogen, phosphorus 208.13 67.96 56.83 107 Lime, nitrogen, potassium 164.48 24.31 13.18 108 Lime, phosphorus, potassium 165.33 25.16 14.03 109 Lime, nitrogen, phosphorus, potassium 214.96 74.79 63.66 110 Nitrogen, phosphorus, potassium 206.28 66.11 Results oe Experiments on Bloomington Field Space is taken to insert Table 6, giving all of the results thus far obtained from the Bloomington soil experiment field, which is also located on the brown silt loam prairie soil of the Illinois corn belt. The general results of the nine years’ work on the Bloomington field tell the same story as those from the Sibley field. The rotations differed by the use of clover and by discontinuing the use of commercial nitrogen, after 1905, on the Bloomington field, in consequence of which phosphorus without commercial nitrogen (Plot 104) produced practically the same increase ($56.05) as was produced by phosphorus over nitrogen on the Sibley field (see Plots 103 and 106). Moultrie County 17 1911] Table 6 Crop Yields in Soil Experiments: Bloomington Field Brown silt loam prairie; Early Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Clover 1906 Corn I 1907 Corn 1908 Oats 1909 Clover 1910f Plot Soil treatment applied Bushels or tons per acre 101 None 30.8 63.9 54.8 30.8 .39 60.8 40.3 46.4 1.56 102 Lime 37.0 60.3 60.8 28.8 .58 63.1 35.3 53.6 1.09 103 Eime, nitrogen 35.1 59.5 69.8 30.5 .46 64.3 36.9 49.4 (.83) 104 Lime, phosphorus 41.7 73.0 72.7 39.2 1.65 82.1 47.5 63.8 4.21 105 Lime, potassium 37.7 56.4 62.5 33.2 .51 64.1 36.2 45.3 1.26 106 Lime, nitrogen, phosphorus 43.9 77.6 85.3 50.9 * 78.9 45.8 72.5 (1.67) 107 Lime, nitrogen, potassium. 40.4 58.9 66 4 29.5 .81 64.3 31.0 51.1 ( -33) 108 Lime, phosphorus, potassium 50.1 74.8 70.3 37.8 2.36 81.4 57.2 59.5 3.27 109 Lime, nitrogen, phosphorus potassium 52.7 80.9 90.5 51.9 * 88.4 58.1 64.2 ( -42) 110 Nitrogen, phosphorus potassium 52.3 73.1 71.4 51.1 * 78.0 51.4 55.3 ( -60) Value oe Crops per Acre in Nine Years Plot Soil treatment applied Total value of nine crops Value of increase 101 102 None Lime $132 15 133.00 $ .85 Over lime 103 Lime, nitrogen (see text) 133.38 1.23 $ .38 104 Lime, phosphorus 189.05 56.90 56.05 105 Lime, potassium 134.24 2.09 1.24 106 Lime, nitrogen, phosphorus 179.16 47.01 46.16 107 Lime, nitrogen, potassium. 130.85 (-1.30) (-2.15) 108 Lime, phosphorus, potassium 191.40 59.25 58.40 109 Lime, nitrogen, phosphorus, potassium 183.29 51.14 50.29 110 Nitrogen, phosphorus, potassium 166.56 34.41 *Clover smothered out by previous very heavy wheat crop. After the clover hay was harvested all ten of the plots were seeded to cowpeas and the crop was plowed under later on all plots as green manure for the 1907 corn crop. fThe figures in parentheses represent bushels of clover seed: the others, tons of clover hay (in two cuttings) in 1910. It should be stated that a draw runs near plot no on the Bloomington field and the crops on that plot are sometimes damaged by overflow or imperfect drainage; also that in 1902 the stand of corn on the Bloomington field was poor, though fairly uniform. Otherwise all results reported ifa Tables 5 and 6, including more than 150 tests, are considered reliable, and they furnish much information and instructive comparisons. Wherever nitrogen was provided either by direct application or by the use of legume crops the addition of the element phosphorus produced very marked increases, the average value being $56.10 for the nine years, or $6.23 an acre a year. This is $3.73 above its cost in 200 pounds of steamed bone meal, the form in which it was applied to these fields. On the other 18 Soil Report No. 2 [June, hand, the use of phosphorus without nitrogen will not maintain the fertility of the soil (see Plots 104 and 106, Sibley field) ; and a liberal use of clover or other legumes is suggested as the only practical and profitable method of supplying the nitrogen, the clover to be plowed under, either directly or as manure, preferably in connection with the phosphorus applied, es- pecially if raw rock phosphate is used. From the best treated plots 130 pounds per acre of phosphorus have been removed from the soil in the nine crops. This is equal to 1 1 percent of the total phosphorus contained in the surface soil of an acre of the untreated land. In other words, if such crops could be grown for 80 years they would require as much phosphorus as the total supply in the ordinary plowed soil. The results plainly show, however, that without the addition of phosphorus such crops cannot be grown year after year. The total phosphorus applied from 1902 to 1910 amounted to 225 pounds per acre. Where no phosphorus was applied the crops removed only 90 pounds of phosphorus in nine years, equivalent to only ?y 2 percent of the total amount (1,200 pounds) in the surface soil at the beginning (1902). The; Subsurface and Subsoil In Tables 7 and 8 are recorded the amounts of plant food in the sub- surface and subsoils, but it should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important information contained in Tables 7 and 8 is that the upland timber soils are more strongly acid in the subsurface and subsoil than in the surface, thus emphasizing the importance of having plenty of limestone in the surface soil to neutralize the acid moisture which rises from the lower strata by Table 7. — Fertility in the Soils oe Moultrie County, Illinois Average pounds per acre in 4 million pounds of subsurface soil (about 6% to 20 inches) Soil Total Total Total Total Total Total Lime- Lime- Type Soil type organic nitro- phos- potas- magne- cal- stone stone No. carbon gen phorus sium sium cium present requir’d Upland Prairie Soils 1126 Brown silt loam 67420 6480 1590 72590 20160 18170 140 1120 Black clay loam (normal phase) . 71140 6220 2650 72340 30020 36350 237C0 1120 Black clay loam (lighter phase) . 30040 4000 2000 65720 38720 38480 82'80 Upland Timber Soils 1132 Bight gray silt loam on tight clay 16740 1840 920 70740 19120 11240 4520 1134 Y ellow-gray silt loam 17650 2040 1100 74680 18530 10230 1840 1*35 Yellow silt loam 17160 1720 1200 80520 2S2S0 8440 6760 Swamp and Bottom-Land Soils 1454 1454 Mixed loam | (normal phase) . Mixed loam (lighter phase) . 71240 48680 | 6240 5680 | 2000 1320 | 80920 81840 I [ 21640 | 20680 | 28720 2S0'0 2200 1000 Terrace Soil 1554.6 Mixed loam over sand or gravel 8960 1360 1040 73720 15440 11720 160 Moultrie County 19 1911 ] capillary action during periods of partial drouth, which are also critical periods in the life of such plants as clover. Thus, while the common brown silt loam prairie soil is practically neutral, the upland soils that are or were timbered are already in need of limestone as a rule; and, as already explained, they are much more deficient in phosphorus and nitrogen than the common prairie. Tabus 8.— Fertility in the Soils or Moultrie County, Illinois Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil Total Total Total Total Total Total Lime- Lime- Type Soil type organic Nitro- Phos- Potas- Magne- Cal- stone stone No. carbon gen phorus sium sium cium present requir’d Upland Prairie Soils 1126 1120 1120 Brown silt loam Black clay loam (normal phase). Black clay loam (lighter phase) . 29180 39230 19800 3720 3670 2340 2230 3130 2280 109670 112730 83760 46360 50690 121020 30790 72840 510720 7860 126200 1638120 Upla nd Timber Soils 1132 Light gray silt loam on tight clay 23280 2670 2070 112380 46770 30990 90 Y ellow-gray 1134 silt loam 18510 2360 1830 126570 41510 18380 5480 1135 Yellow silt loam 14820 2100 2040 143400 46200 16140 480 Swamp and Bottom-Land Soils 1454 Mixed loam (normal phase). 41760 4500 | 2160 | 127020 34260 35580 1020 1454 Mixed loam (lighter phase) . 39360 4500 1920 1 118200 28320 32580 5340 Terrace Soil 1554.6 Mixed loam over sand or gravel 7980 1380 1320 2580 101460 26340 16740 20 Soil Report No. 2 [June, INDIVIDUAL SOIL TYPES (a) Upland Prairie Soils Brown Silt Loam (1126) This type occupies 77.5 percent of the area of the county or 264.42 square miles, equal to 169,229 acres. It has been formed from wind- blown loessial material mixed with organic matter furnished by the roots of prairie grasses that formerly grew on the native prairies. The topog- raphy varies from nearly flat to rolling, the larger part of the type being sufficiently sloping to insure good surface drainage, while the rest is in good condition for tile drainage. The surface soil, o to 6% inches, is a brown silt loam, but near the boundaries it varies on the one hand to almost black as it passes toward black clay loam, and on the other to a grayish brown or yellowish brown as it grades into the timber types. It contains enough of the coarser con- stituents,, sand and coarse silt, to make it work easily, and yet enough clay to give stability to the soil. The organic matter content varies from 3L2 to 5 percent, the amount depending upon topography to a considerable extent. The lower and more poorly drained areas permitted the accumula- tion of a larger amount than the higher land because of ranker growth of grasses as well as less decay on account of moisture. The thickness of the subsurface varies from 7 to 14 inches, and in color from a dark brown to a light yellowish brown silt loam, the color and depth varying with the topography, being lighter in color and shallower on the more rolling areas. The subsoil to a depth of 40 inches is a yellow clayey silt or silty clay, somewhat plastic when wet. The color is of >a brighter yellow, even somewhat reddish, where there has been good surface drainage, and of a pale yellow, approaching an olive color, where poorly drained. In some of the rolling areas the loess deposit has been partly removed by washing, thus bringing the glacial drift within 40 inches of the surface. This is of rare occurrence in Moultrie County. In the management of this soil, one necessary thing, aside from proper drainage and good tillage, is to keep it in good physical condition or in good tilth. It is a common practice in the corn belt to pasture the corn stalks during the winter and often late in the spring, so late in fact that tramping puts the soil in bad condition for working. It is partially puddled and will be cloddy as a result. If thus tramped in the spring, the natural agencies of freezing and thawing, wetting and drying, even with the aid of ordinary tillage, fail to produce good tilth before the crop is planted and the latter necessarily suffers. This will be much worse if the season should be dry. A poor stand of corn will result, if the field is put in corn, and a compact baked soil unfavorable for growth, if put in oats. Sometimes farmers will not wait for their soils to become sufficiently dry to work well, and a puddled soil results which is very unfavorable to physical, chemical, and biological processes. This will be especially true if cropping has reduced the amount of organic matter below what is necessary to maintain good tilth. Every practicable means should be used to maintain the supply of this constituent. Clover should be grown every three or four years and the bulk of the crop turned under, either directly or after removing the seed Moultrie County 21 19 II] or after feeding and bringing back all the manure. All straw should be returned to the land and plowed under if not used as bedding or fed, and stalks should be chopped up and turned under as well as weeds and trash. In this way only can the present fair supply of organic matter and its accompanying nitrogen be maintained in this soil. The supply of phos- phorus as shown by field experiment is inadequate for the highest economical production, and this should be increased by turning under with the clover sod every three or four years at least one-half ton of rock phosphate per acre, and the initial application may well be a ton or more per acre. On the lighter phase of the type and upon higher points of the better phase, the immediate use of ground limestone per acre (about two tons every four or five years) is to be recommended. In the near future, for the continued successful growing of clover, alfalfa, and other legumes, limestone will generally have to be used upon this type of soil. Black Clay Loam (1120) This type of soil, commonly found in the originally swampy or poorly drained areas of the Early Wisconsin Glaciation, is frequently called “gumbo,” because of its sticky character. Its formation in these low places is due to the accumulation of organic matter and the washing in of the clay and other fine material from the slightly higher uplands. On account of the good surface drainage that exists generally in this county, the black clay loam constitutes only 4.5 percent of the entire area, or 9,858 acres. The topography of this type is flat, yet for all areas of black clay loam sufficient “outlets” for tile may be secured so that good drainage is possible The surface stratum, o to 6 Ys inches, is a black, plastic clay loam con- taining from 5 to 7 percent of organic matter, or from 50 to 70 tons in an acre. The surface soil is naturally quite granular and consequently pervious to water. This granular character is a very desirable property for all soils, but especially for heavy ones. It keeps the soil mellow and if the granules are destroyed by working while wet or by the tramping of stock, they will be formed again by freezing and thawing and by moisture changes (wetting and drying). These produce slacking, as the process is usually termed. If, however, the humus and lime content become low, this tendency to granulate grows less and the soil becomes more difficult to work. The subsurface stratum, from 10 to 16 inches thick, is about the same as the surface, except that it becomes lighter with depth so that the lower part of this stratum may pass into a drab or yellowish silty clay. It is pervious to water, due to the jointing or checking produced by shrinkage in times of drouth. The subsoil below 20 inches is usually a drab or dull yellow silty clay but locally may be a yellow clayey silt. As a rule the subsoil is not so highly colored as that of the better drained types, due to the fact that the iron is not so highly oxidized in this poorly drained subsoil. The subsoil is checked and jointed somewhat the same as the subsurface. This type presents many variations. It must be borne in mind that the boundary lines between different soil types are not always distinct but that types frequently pass from one to the other very gradually, thus giving a zone of greater or less width intermediate between the two types. The black clay loam (1120) is usually surrounded by brown silt loam (1126) 22 Soil Report No. 2 [June, and it would be expected that the two would grade into each other. This gives variations including a lighter phase containing less of clay and organic matter than the average of the type. In some areas there has been enough silty material washed in from the surrounding higher land to modify the character of the surface soil. This is true of the Eagle Pond district in Sections 14, 23, 24 and 26, in Township 14 North, Range 5 East of the Third P.M., and particularly in small areas surrounded by higher land. This change is taking place more rapidly now with annual cultivation of soil than formerly when prairie grass protected the land from washing. The amount of coarse soil constituents, sand and gravel, varies in this type. These have been brought up to some extent from the underlying glacial drift by burrowing animals, especially crayfish, and distributed thru the soil. Drainage is the first requirement of this type, and altho but very slightly sloping, yet this with the perviousness of the soil gives an excellent chance for surface and tile drainage. Keeping the soil in good physical condition is very essential, and thoro drainage helps to do this to a great extent. As the organic matter is destroyed and the lime removed from the soil, the former by cultivation and decomposition and the latter by cropping and leaching, the soil will attain a poorer physical condition and consequently become more difficult to work. Both the organic matter and the lime tend to develop granulation of the soil. The former should be maintained by turning under manure or clover and residues from crops, such as cornstalks, stubble and straw, and ground limestone should be applied where needed. While this soil is one of the best in the s tate, ve t the clay and humus which it contains give it the property of shrinkage and expansion to such a degree as to be somewhat objectionable at times. When the soil is wet, these constituents expand, and when the moisture evaporates or is used by plants; the soil shrinks. This results in the formation of cracks up to two inches or more in width and extending with lessening width to a depth of a foot or more. These cracks allow the subsoil to dry out rapidly. They sometimes “block out” the hills of corn by cross cracks, severing the roots and thus confining each hill to a comparatively small area. Sometimes much damage to the crop results. While cracking may not be prevented entirely in this type, yet it may be controlled to some extent by a soil mulch to check evaporation and prevent the cracks from extending to the surface. Organic matter, as cornstalks or straw, applied to the surface in liberal amount, also makes a very Satisfactory mulch, but of course this would interfere with ordinary cultivation and cropping. This type of soil is well supplied with organic matter and nitrogen. It has about eighty percent more phosphorus than does the brown silt loam and is abundantly supplied with potassium. As a rule, it contains limestone in sufficient amounts for present use. Upon this soil* it is of first importance to establish a system which will maintain the supply of actively decaying organic matter and to so handle it as to keep the soil in good tilth. Eventu- ally the use of limestone and phosphorus may be profitable; and on the lighter phase, indicated by the lighter color and greater friability (because of its higher content of silt), applications of phosphorus can even now be made profitable in good systems of farming. Moultrie County 23 /P'J] (b) Upland Timber Soies Light Gray Silt Loam on Tight Clay (1132) This type comprises only 1.4 percent of the area of the county or 3,040 acres. It is found almost entirely in the southern part of the county in the timbered areas along the Kaskaskia river and its tributaries. As a rule, it occurs in small, level, but not swampy areas that have poor drainage on account of the topography and the imperviousness of the subsoil. Practi- cally all of this type is now cleared and under cultivation, but the trees formerly growing upon it were white oak, shellbark hickory, black jack and some post oak. The surface soil, o to 6^3 inches, is a light gray silt loam, incoherent, friable, and porous. Iron concretions, varying in size from *4 inch to a pin head are usually present in this stratum. The organic matter content is very low, being about 1 *4 per cent. The subsurface is a light gray silt becoming slightly yellowish and more clayey with depth. The subsoil below 20 inches is a compact clayey silt, yellow in color with gray or drab mottlings. The subsoil below 35 or 40 inches is usually coarser and' more pervious to water. The soil runs together after a rain, and limestone with organic matter will prevent this to a very great extent. Some carefully conducted experiments are needed to ascertain the feasi- bility of tile-drainage in this land. In the management of this type the most practical things to do are to apply limestone and phosphorus and increase the content of organic matter in every way practicable. The subsoil is tight and the growing of deep- rooting crops such as red, mammoth, or sweet clover would tend to make it more porous as well as supply the soil with organic matter and nitrogen. Y ellow-Gray Silt Loam (1134) This type occurs in the timbered area along the Kaskaskia river and its tributaries, principally in the southern part of the county, forming strips along the streams with a broadening toward the north and east sides of the streams where the timber was protected from the prairie fires driven by the prevailing south-westerly winds. The type occupies about 10.3 percent of the total area of the county or 22,412 acres, being next in amount to the brown silt loam. This type is sufficiently rolling for good drainage without much tendency to wash, if anything like proper care is taken of the soil. The surface soil, o to 6^3 inches, Is a gray to yellowish gray silt loam, incoherent and mealy but not granular. It is low in organic matter content, averaging about 2^4 per cent. The characteristic stratum in the subsurface varies from 3 to 10 inches in thickness and consists of a gray, grayish yellow, or yellow; silt loam, somewhat mealy but becoming more coherent and clayey with depth. Only a small amount of organic matter is present. The subsoil is a yellow or grayish mottled yellow clayey silt or silty clay, somewhat plastic when wet, but friable when only moist. Where erosion has occurred, glacial drift sometimes forms all or part of the subsoil. 24 Soil Report No. 2 [June, This type is quite variable, due to the fact that it grades into so many different types. It is very probable that all or very nearly all of the tim- bered area was at one time a part of the prairie and the present character of the soil has been produced by the gradual invasion and long occupancy of forest growth. Certain trees, such as elm, hard maple, wild cherry, hack- berrv, and black walnut, were the first to spread over the prairie. Long periods (perhaps thousands of years) were required to produce much change in soil. Other trees followed the above, and the growth of grasses to which the accumulation of organic matter is largely due was gradually diminished by shading and growth of underbrush, after which little or no organic matter was added and incorporated with the soil. The leaves of the trees falling upon the surface were either burned or decayed completely without being mixed with the soil and gradually the organic matter content was reduced until a gray silt loam or a yellow-gray silt loam was the result. There is frequently a zone of land (too narrow to map) that repre- sents a transition between the brown silt loam and the timber type in which the surface soil is brown or grayish brown and the subsurface is grayish brown to gray. This gives a phase of the type that is better than the average, especially as to its content of organic matter. The topography is generally undulating to rolling, becoming in some places sufficiently rolling so that considerable washing may occur if not properly managed. To prevent this washing, as well as to supply a deficient and much needed constituent, every practicable means should be employed to increase the oreanic matter content of this type. “Running together” is a fault of this soil that may thus be largely prevented. The absence of limestone in the subsoil indicates the advisability of using limestone upon this soil in order to grow clover, alfalfa, and other legumes more successfully. The soil is also very deficient in phosphorus, which must be liberally supplied in any practicable system for the marked and profitable improvement of this soil. Yellow Silt Loam (1135) This type covers only 1,402 acres, or le9s than one percent of the total area of the county. It occurs as narrow irregular strips adjoining the bottom-lands of the Kaskaskia river, or as arms projecting into other types and marking the location of small streams that have eroded to considerable depth. The topography is very rolling to broken, so steep in many places that it cannot be cultivated and much of it should not be, because of the danger of injury from washing. The surface soil, o to inches, is a grayish yellow, pulverulent, mealy silt loam, somewhat porous. 'Where much recent washing has taken place, the surface soil does not differ materially from the subsoil. The typical subsurface varies considerably, depending upon the amount of washing that has taken place. In thickness it varies from o to 12 inches, the variation being due to the removal of the surface. In fact, in many places both surface and subsurface have been removed exposing the subsoil. This latter consists of a compact yellow clayey silt but in places the glacial drift may form the whole or part of the subsoil, or occasionally it may even form the surface soil in small patches. Moultrie County 25 1911] In the management of this type the chief thing is to prevent general surface washing and gullying. If it is cropped at all, a rotation should be practiced that will require a cultivated crop as little as possible and allow as much pasture or meadow as possible. If tilled, the land should be plowed deeply and contours should be followed as nearly as possible. Furrows extending up and down the slopes should be avoided. Planting and cultiva- tion should be done in the same direction as plowing. Every means should be employed to maintain and increase the organic matter content to help hold the soil and keep it in good physical condition so it will absorb a large amount of water and thus diminish the run off. (See Circular 119.) Limestone can be used with profit on this type of. soil where it is to be cropped or prepared for seeding down. Even top-dressings of limestone will usually help to increase the leguminous plants in the herbage of perma- nent pastures. The application of phosphorus is not advised, unless special precautions are taken to prevent surface erosion; and, if used at all, the phosphorus should be mixed with the surface soil by disking and then plowed under, so as to put the phosphorus down where the plant roots feed, and thus reduce the danger of loss of applied phosphorus by erosion. (c) Swamp and Bottom-land Soils Bottom-lands are usually named from their distances above the streams as first, second, third, etc. The first bottom represents the flood plain of the stream. The highest bottom is the oldest and shows the height to which the old valley was once filled. Mixed Loam (1454; The first bottom or overflow land along the streams in the county is called mixed loam. These small bottom lands vary a great deal in the kind of soil, and the areas of these different types are so small that it would be entirely impracticable to separate them. Moreover, the soils are changed by floods so that a separation of types would not mean very- much after a few years. The total area is only 8,781 acres, or a little more than four percent of the area of the county. The topography is generally flat, but occasionally an area is found that has undulating surface due to the overflow stream channels that give a little diversity to the topography. The surface soil, o to inches, varies from a dark brown silt loam, or even clay loam, to a brown loam and light brown sandy loam. The lower and more nearly level areas are heaviest and blackest while the undulat- ing areas are more loamy and sandy. The subsurface soil is very similar to but lighter in color than the surface. There is sometimes no distinct line separating the subsurface from the subsoil, the only difference frequently being a lighter color. In the sandy areas the subsoil is generally more sandy, sometimes becoming a sand. While the normal phase is only moderately rich and the lighter phase is rather low in nitrogen and phosphorus, the soil is usually very deep and thus affords a very extensive feeding range for plant roots. Drainage and protection from overflow are the considerations of first importance in dealing with this soil. 26 Soil Report No. 2 [June, (d) Terrace Soils Mixed Loam over Sand or Gravel (1554.6) This type which forms only 1.6 percent of the area of the county, or 3,516 acres, occurs along the Kaskaskia proper and the West Fork of that stream. The areas are somewhat isolated and represent an old fill or bottom-land probably formed by the melting of the Wisconsin Glacier at a time when the river was overloaded with ground-up material from the melting glacier. The streams have later cut down thru this deposit and developed a new bottom that is from 10 to 30 feet below the terrace. Much of the material that , filled this old valley was gravel and coarse sand which now form the underlying stratum of this type. The topography varies from almost level to a gentle slope and in some areas gently undulating. The surface soil, o to 6 2 A inches, varies from a brown or yellow silt loam to a loam or sandy loam. The variations are in too small areas to permit their being shown separately on the map. As a general rule, there is more sand in the soil near the first bottom than farther back. This is probably due to the sand being blown up from the lower bottom-land. The subsurface stratum is from 6 to 12 inches in thickness, being a light brown to yellow silt loam with variations of sand content similar to that of the surface soil. The subsoil is a yellow silt varying to a sandy silt or sandy loam sufficiently open and pervious to allow good drainage. Underlying the subsoil at a depth of from three to six feet is a bed of gravel or sand that provides good underdrainage. In dry seasons where the gravel is nearest the surface, the crop may suffer from drouth because of the inability of the gravel to draw the moisture up from below on account of its coarseness and consentient low capillary power. This soil is one of the poorest in the area in phosphorus, nitrogen, and organic matter, thus resembling the yellow silt loam, from which it re- ceives some surface wash in places; but its topography is such as to justify the adoption of definite plans for improving this soil to a high state of productiveness. Large use of organic manures and liberal applications of phosphorus are the chief essentials, the addition of phosphorus being less important on the more sandy areas, because of the deep feeding range there afforded for plant roots. In places the soil is acid and as an average the subsurface and subsoil are acid. In soils of such variable character the landowner should thoroly test the soil and subsoil for acidity, using a few cents’ worth of blue litmus paper and following the directions given in Circular no, “Ground Limestone for Acid Soils,” which also contains directions for making a machine for spreading phosphate and limestone, and will be sent to any one free of charge upon application to the Agricultural Experiment Station. Moultrie County 27 1911] APPENDIX A study of the soil map and the tabular statements concerning crop re- quirements, the plant food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil improvement, and a careful study of the discussion of general prin- ciples and of the descriptions of individual soil types will furnish the most necessary and useful information for the practical improvement and perma- nent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and important soil types in the great soil areas in all parts of Illinois is contained in Bulle- tin No. 123, “The Fertility in Illinois Soils,” which contains a colored gen- eral survey soil map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils.” Bulletin No. 94, “Nitrogen Bacteria and Legumes.” Bulletin No. 99, “Soil Treatment for the Lower Illinois Glaciation.” Bulletin No. 115, “Soil Improvement for the Worn Hill Lands of Illinois.” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois.” Circular No. no, “Ground Limestone for Acid Soils.” Circular No. 127, “Shall we use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils ?” Circular No. 129, “The Use of Commercial Fertilizers.” Circular No. 149, “Some Results of Scientific Soil Treatment” and “Methods and Re- sults of Ten Years’ Soil Investigation in Illinois.” NOTE. — Information as to where to obtain limestone, phosphate, bone meal, and po- tassium salts, methods of application, etc., will also be found in Circulars no and 149. Soil Survey Methods The detail soil survey of a county consists essentially of indicating on a map the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential : first, careful, well-trained men to do the work ; second, an ac- curate base map upon which to show the results of their work; and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal varieties and lim- its, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will survey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries will match up on the line between the two strips. 28 Soil Report No. 2 [June, An accurate base map for field use is absolutely necessary for soil map- ping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construction of these maps, while the most trustworthy county map available is used in locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and corrected if wrongly located. In order to make these verifications and corrections, each survey party is provided with an odometer for measuring distances, and a plane table for determining the directions of roads, rail- roads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, additional streams, and necessary corrections are placed with proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils being carried in the field for this purpose. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is taken by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while dis- tances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be lo- cated with as high a degree of accuracy as ^an be indicated by pencil on the scale of one inch to the mile. Soil Characteristics The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between ad- joining types is usually distinct, but sometimes one type will grade into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, alluvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical or mechanical composition of the different strata composing the soil, as the percentages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. I9ii] Moultrie County 29 The common soil constituents are indicated in the following outline : Soil Constituents Constituents of Soils Organic j Comprising undecomposed and partially decayed Matter j vegetable material Inorganic Matter f Clay ooi mm.* and less Silt ooi mm. to .03 mm. -j Sand 03 mm. to 1. mm. Gravel 1. mm. to 32 mm. [ Stones 32. mm. and over. *25 millimeters equal 1 inch. Further discussion of these constituents is given in Circular 82. Groups of Soil Types The following gives the different general groups of soils : Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand and silt and a little clay. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and some silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 25 to 50 percent gravel with much sand and some silt. Gravels- — Soils with more than 50 percent of gravel. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no agricultural value. More or less organic matter is found in nearly all of the above classes. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which this is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly im- portant, is not a positive but a negative factor in crop production. 30 Soil Report No. 2 [June, The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but the rate of liberation is governed by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are lime- stone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may also be supplied by green-manure crops and crop residues, such as clover, cowpeas, straw, and cornstalks. The rate of decay of organic matter de- pends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which repre- sents, as a rule, but little more than half the organic matter: so that 20,000 pounds of organic carbon in the plowed soil of an acre corresponds to nearly 20 tons of organic matter. But this organic matter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20 tons of old inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent ad- ditions of active organic matter, whether in applications of farm manure, in legume crops, or in grass-root sods of old pastures. Probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even though plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that with the normal rainfall of Illinois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such commodity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing nitrates, phosphates, and other salts of potas- sium, magnesium, calcium, etc. for the use of the growing crop. As already explained fresh organic matter decomposes much more rap- idly than the old humus, which represents the organic residues most resistant to decay and which consequently have accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and which thus furnish or liberate organic matter and in- organic food for bacteria, which, under such favorable conditions appear to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by Moultrie County JpT/] itself, becomes much more effective when incorporated with fresh farm manure ; so that, when used together, two tons of the mixture may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bacterial action is also promoted by the presence of limestone. It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are se- cured from the air by all plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (le- gumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches among our common .agricultural plants) secure only from the soil six elements (phosphorus, potassium, magnesium, calcium, iron and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of these plant-food elements in just the same sense that a building is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay; and, where the land is properly drained and properly tilled, such crops would frequently be secured if the plant foods were pres- ent in sufficient amount and liberated at a sufficiently rapid rate to meet the absolute needs of the crops. Crop Requirements The accofnpanying table shows the requirements of such crops for the five most important plant food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are not known ever to limit the yield of crops) : Table A Plant Food in Wheat, Corn, Oats, and Clover Produce Nitro- gen, pounds Phos- phorus, pounds Potas- sium, pounds' Magne- sium, pounds Cal- cium, pounds Kind Amount Wheat, grain SO bu. 71 12 13 4 1 Wheat straw 2 Yz tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs Yz ton 2 2 Oats, grain 100 bu. 66 11 16 2 Oat straw 2 y 2 tons 31 5 52 7 15 Clover seed 4 bu. 7 2 3 1 1 Clover hay 4 tons 160 20 120 31 117 Total in grain and seed 244* 42 51 16 4 Total in four crops . . . 510* 77 322 68 168 *These amounts include the nitrogen contained in the clover seed or hay, which, however, may be secured from the air. 32 Soil Report No. 2 [June, To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as pos- sible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the 100-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has pro- duced, as an average of the six years, 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with limestone, phosphorus, and manure). On the Fairfield Experiment Field in Wayne County, on the common prairie land of southern Illinois, yields have been obtained as high as 90 bushels per acre of corn, and 3*4 tons of air-dry clover hay. The importance of maintaining a rich surface soil cannot be too strongly emphasized. It is well illustrated by data from the Rothamsted Experiment Station, the oldest in the world. Thus on Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years, 1892 to 1901 were 12.3 bushels per acre on plot 3 (unfertilized) and 31.8 bushels on plot 7 (well fertilized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in plot 3 than in plot 7, thus showing that the higher yields from plot 7 were due to the fact that the plowed soil had been enriched. In 1893, plot 7 contained per acre in the surface soil (o to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods op Liberating Plant Food Limestone and decaying organic matter are the principal materials the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the boil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria which have power to transform the insoluble and unavail- able organic nitrogen into soluble and available nitrate nitrogen. At the same time the products of this decomposition have power to dis- solve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by per- mitting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing whatever to the soil, but always leaves the soil poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root development and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to im- prove the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Moultrie County 33 1911] Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows: ( 1 ) If the soil is acid apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC0 3 MgC0 3 ) which contains both calcium and magnesium, and has slightly greater power to correct soil acidity, ton for ton, than the ordinary calcium limestone (CaC0 3 ) ; and continue to apply about two tons per acre of ground limestone every four to six years. ( 2 ) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn Stalks) or by using for feed and bedding practically all of the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are sug- gested to serve as models or outlines : First year, corn (with some winter legume, such as red clover, alsike, sweet clover, or alfalfa, or a mixture, seeded on part of the field at the last cultivation). Second year, oats or barley or wheat (fall or spring) on one part and cowpeas or soybeans where the winter catch crop is plowed down late in the spring. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the ro- tation. In grain farming, with wheat grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five-year rotation by cutting out either the second or the sixth year; and to a four-year system by omitting the fifth and sixth years. With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are: Wheat (and clover), corn, oats, and clover; or corn (and clover), cow-peas, wheat and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are : Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cow-peas, in which two catch crops and one regular crop of legumes are grown in three years. 34 Soil Report No. 2 [June, A five-year rotation of corn (and clover), cow-peas, wheat, clover, wheat (and clover) allows legumes to be seeded four times, and alfalfa may be grown on a sixth field for five or six years in the combination rotation, alternating between two fields every five years, or rotating over all fields if moved every six years. I o avoid clover sickness it may sometimes be necessary to substitute red clover or alsike for the other in about every third rotation, and at the same time to discontinue their use in the catch-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a catch-crop (seeded at the last cultivation) in the southern part of the state and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named : 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires i l / 2 pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. 1 ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. For grain crops, as wheat, corn, and oats, about two- thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in considerably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far se- cured shows positively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary sys- tems of permanent, profitable soil improvement. The first application may well be one ton per acre, and subsequently about one-half ton per acre every four to six years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total application of from three to five or six tons per acre of raw phos- phate containing 12)^ percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in car- load lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phosphate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about ip2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) Moultrie County 35 19a] The phosphate and limestone may be applied at any time during the rotation, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply of decaying organic matter has been made ade- quate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as to furnish available potas- sium and magnesium, and for a few years such use of kainit will no doubt be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for decaying organic mat- ter, since this will necessitate returning to the soil either all produce except the grain (in grain farming) or the manure produced in live-stock farm- ing. (Where hay or straw are sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow- gray silt loam, and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tend to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently ; but where such lands are farmed under such a system not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time ; and where the soil is acid a liberal use of limestone, as top dressings if necessary, and occasional re- seeding with clovers will benefit both the pasture and indirectly the grain crops. Advantage oe Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years; but even a partial stand of clover the first time will probably provide a thousand times as many bac- teria for the next clover crop as ong could afford to apply in artificial inocu- lation, for a single root-tubercle Thay; contain a million bacteria developed from one during the season’s growth’. This is only one of several advantages of the second course of the rota- tion over the first course. Thus the there practice of crop rotation is an ad- vantage, especially in helping to rid 'tKe land of insects and foul grass and weeds. The deep-rooting clover crop is’ an advantage to subsequent crops because of that characteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage; and in systems of permanent soil improvement, such as are here advised and illustrated, more limestone and more phosphorus are provided than are needed for the meager or moderate crops produced during the first rotation, and conse- quently the crops in the second rotation have the advantage of such accumu- 36 Soil Report No. 2 [June, latecl residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. This means that these systems tend positively toward the making of richer land. The ultimate analyses recorded in the Tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter ; and the accumulated information from careful and long-continued investiga- tions in different parts of the United States clearly establish the fact that in general farming these essentials can be supplied with greatest economy and profit by the use of ground natural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applications are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt such as kainit is used it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 59 years (1852 to 1910) the yield of wheat has been 12.7 bushels on un- treated land, 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied; and, as further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of mag- nesium raised it to 29.3 bushels; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied the average wheat crop re- moved 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained abundance of limestone, but no organic matter was provided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 59 years (1852 to 1910) has been 14.4 bushels on untreated land, 38.6 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus have been applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.7 bushels, but, where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average has been 43.3 bushels. Thus, as an average of 59 years, the use of sodium pro- duced 1.8 bushels less wheat and 1.6 bushels more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop; but this must be expected to occur in time where no potassium is returned in straw or manure, and no provision made for liberating potassium from the supply still remaining in the soil. If more than three-fourths of the potassium removed were returned in the straw (see Table A), and if the decomposi- jp/j] Moultrie County 37 tion products of the straw have power to liberate additional amounts of po- tassium from the soil, the necessity of purchasing potassium in a good system of farming on such land is very remote. While about half of the potassium, nitrogen, and organic matter, and about one-fourth of the phosphorus, contained in manure, will be lost by three or four months’ exposure in the ordinary pile in the barn yard, there .is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while the animals destroy two-thirds of the ■organic matter and retain one-fourth of the nitrogen and phosphorus in -average live-stock farming, they retain less than one-tenth of the potassium, from the food consumed; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 6^ inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent ■cultivation) would permanently maintain the potassium in grain farming by renewal from the subsoil, provided one-third of the potassium is removed ■by cropping before the soil is carried away. From all of these facts it will be seen that the potassium problem is not one of supply but of liberation; and the Rothamsted records show that for many years other soluble salts have practically the same power as po- tassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability ■of phosphorus or other elements, it is not known, but where much potassium is removed, as in the entire crops at Rothamsted with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909 and 1910, on the Fairfield Experiment Field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium costing $5.10, in- creased the yield of corn by 9.3 bushels per acre; while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4.00, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit has paid for itself ; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield include an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure had been applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bush- els, while the 600 pounds of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was pro- duced by the addition of either potassium sulfate or kainit; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for: and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant food ele- ments, especially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown that potassium salts and most other soluble salts increase the solubility of the phosphorus in soil and in rock phosphate as determined bv chemical analysis; also that the addition of glucose with rock phosphate in 38 Soil Report No. 2 pot-culture experiments increases the availability of the phosphorus, as meas- ured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, add thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the organic matter of the food consumed, it is easy to determine from Table A that more organic matter will be supplied in a proper grain sys- tem than in a strictly live-stock system; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious in- terference with the capillary movement of - the soil moisture, a common danger from plowing under too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming, or when both grain and straw are sold, of course the draft on potassium will then be so great that in time it must be renewed by some sort of application. As a rule, such farmers ought to secure manure front town, since they furnish the bulk of the material out of which the manure is produced. Calcium and Magnesium When measured by the actual crop requirements for plant food, mag- nesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses* of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of mag- nesium, and 330 of caldium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of mag- nesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in 1905. And practically the same amount of calcium was found by analyzing the Rothamsted drainage waters. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. (See Soil Report No. 1.) Thus limestone has a posi- tive value on some soils for the plant food which it supplies, in addi- tion to its value in correcting soil acidity and in improving the physical condition of the soil. Ordinary limestone (abundant in the southern and western parts of the State) contains nearly 800 pounds of calcium per ton; while a good grade of clolomitic limestone (the more common limestone of northern Illinois) contains about 400 pounds of calcium and 300 pounds of magnesium per ton. Both of these elements are furnished in readily available form in ground dolomitic limestone. *Reported by Doctor Bartow and associates, of the Illinois State Water Survey. UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 3 HARDIN COUNTY SOILS By CYRIL, G. HOPKINS, J. G. MOSIER, J. H. PETTIT and J. E. READHIMER URBANA, ILLINOIS, AUGUST, 1912 State Advisory Committee on Soil Investigations Ralph Allen, Delavan F. I. Mann, Gilman A. N. Abbott, Morrison J. P. Mason, Elgin C. V. Gregory, Chicago Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief in Agronomy and Chemistry Soil Survey — J. G. Mosier, Chief A. F. Gustafson, Associate S. V. Holt, Assistant H. W. Stewart, Assistant H. C. Wheeler, Assistant F. A. Fisher, Assistant P. E. Karraker, Assistant F. M. W. Wascher, Assistant Soil Analysis — J. H. Pettit, Chief E. Van Alstine, Associate J. P. Aumer, Assistant Gertrude Niederman, Assistant W. H. Sachs, Assistant W. R. Leighty, Assistant J. T. Flohil, Assistant Soil Experiment Fields — J. E. Readhimer, Superintendent Wm. G. Eckhardt,* Associate O. S. Fisher, Assistant J. E. Whitchurch, Assistant E. E. Hoskins, Assistant F. W. Garrett, Assistant F. C. Bauer, Assistant Soils Extension — C. C. Logan, Associate f On leave. HARDIN COUNTY SOILS By CYRIE G. HOPKINS, J. G. MOSIER, J. H. PETTIT and J. E. READH1MER Introduction The counties of Hardin, Pope, Johnson, Union, Alexander, Pulaski and Massac include most of the unglaciated area of southern Illinois. The Ozark Hills extend across this area from west to east, and in places project into the next tier of counties on the north. The hill lands represent the most extensive soil types in these seven counties, altho the bottom lands are also very important, and quite extensive in the southern portion, including the Mississippi, Ohio, Cash and Big Bay bottoms. Hardin county is representative of the unglaciated area in southern Illi- nois, but the information contained in this report on “Hardin County Soils” is applicable not only to the other counties in this area, but also to the hill lands in the lower Illinoisan glaciation lying between the Ozark Hills and the corn belt; and even in the corn-belt counties there are some hill lands, especially near the larger streams, whose chief difference from the Ozark Hills is the lower degree of acidity in the northern soils. For information concerning the soils of the prairie counties of the wheat belt of Illinois, the reader is referred to Soil Report No. I, “Clay County Soils”; and for information concerning most of the important soil types of the corn belt, he is referred to Soil Report No. 2, “Moultrie County Soils.” In addition it may be stated that Bulletin 123, “The Fertility in Illinois Soils,” shows the great soil areas of the state and gives the composition of the most important soil types in each area and much information relating to their improvement. Soil Formation Hardin county is situated in the southeastern part of the state on the Ohio river, entirely within the unglaciated area. The altitude above sea level varies from slightly over 300 feet to more than 800 feet, thus giving a relief of 500 feet in the county, the topography over almost the entire county being characterized by hills and valleys. As a result of the topography and of the somewhat heavy rainfall, water has been and is now a very active agent in soil formation or modification. The chief material composing the soils of Hardin county is a wind-blown dust known as loess. Altho the county has never been glaciated it has no purely residual soil formed by the disintegration and partial decomposition 2 Soil Report No. 3 [August, of rocks in place, the residual material having been buried beneath the de- posit of loess to a depth of 5 to 20 feet, altho on some of the stony slopes the soil is a mixture of residual and wind-blown material, and might prop- erly be called residuo-loessial or residuo-aeolial soil. The following table gives the soil types, the areas in acres and square miles, and the percentage of each type of total area in the county. Table 1. — Soil Types of Hardin County Soil type No. Names Area in square miles Area in acres Percent of total 135 (a) Upland Timber Soils (page 13) Yellow silt loam 120.15 76,896.0 70.56 134 Yellow-gray silt loam 10.50 6,720.0 6.17 864 Yellow fine sandy loam .46 294.4 .27 198 Stony loam 17.05 10,912.0 10.01 199 Rock outcrop 3.58 2,291.2 2.10 1323 (b) Swamp and Bottom-land Soils (page 18)- Red-brown clay loam 3.16 2,022.4 1.86 1331 Deep gray silt loam 1.20 768.0 .66 1361.1 Mixed fine sandy loam : 12.61 8,070.4 7.40 1380 River sand .20 130.5 .12 1516 (c) Terrace Soils (page 20) Gray clay .31 195.8 .17 1530 Gray silt loam on tight clay. 1.18 755.2 .68 Totals 170.40 109,055.9 100.00 THE INVOICE AND INCREASE OF FERTILITY IN HARDIN COUNTY SOILS Soil Analysis To appreciate the value of the essential elements of fertility for crops, we should keep in mind that food for plants is just as important as food for animals. In the Appendix will be found a more comprehensive discussion of this general subject, which should be read and studied in advance by those who are not familiar with the fundamental principles involved; and in any case the reader should carry in mind the plant food requirements for crops and the loss of plant food from soils by leaching. (See Table A and the closing pages of the Appendix.) In brief, all agricultural plants are composed of ten elements of plant food, of which two (carbon and oxygen) are secured from the air, one (hydrogen) from water, and seven (nitrogen, phosphorus, potassium, mag- nesium, calcium, iron, and sulfur) are taken from the soil. Legume crops, such as the clovers, peas, and beans, may, under suitable conditions, secure more or less of their nitrogen from the air in case the amount furnished by the soil is insufficient. The supply of iron in soils is so great that it need not be further considered, and so far as we know the supply of sulfur in the soil, supplemented by the sulfur brought to the soil in rain and otherwise, is sufficient to meet all requirements of common farm crops for that ele- ment. We need to give special consideration to the five elements nitrogen, phos- phorus, potassium, magnesium, and calcium, and in addition we should not only provide against soil acidity, but insure the presence of limestone. POPE COUNTY R. 7 E SALINE ). ? HARDIN COUNTY UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION terrace soils Reddish brown clay loam UPLAND TIMBER SOILS Yellow-gray silt loarr ne sandy loam Yellow fir Hardin County 3 1912] In Table 1 are recorded the average amounts of these important elements per acre to a depth of 6% inches for all of the different types of soil in Hardin county. The table also shows the amount of limestone, if present, or the amount of limestone required to neutralize or destroy the acidity pres- ent. The organic carbon is the best measure of the organic matter (par- tially decayed vegetable matter) ; and, as explained in the Appendix, the ratio of carbon to nitrogen gives some indication of the age or condition of the organic matter. Approximately one-half of the organic matter of the soil is carbon, so that 12,880 pounds of carbon, for example, correspond to about 12 tons per acre of organic matter. Two million pounds per acre (about 6 2 /t, inches deep) represents at least as much soil as is ordinarily turned in plowing. This is the soil with which we finally incorporate the farm manure, phosphate, limestone, or other fertilizer applied to the soil ; and this is the soil stratum upon which we must depend in large part to furnish the necessary plant food for the production of the common crops, as will be better understood from the in- formation given in the Appendix. As there stated, even a rich subsoil has but little value if it lies beneath a worn-out surface. If, however, the surface soil is enriched, the strong, vigorous plants will have power to secure more plant food from the subsurface and subsoil than would be the case with weak, shallow-rooted plants. Table 2. — Fertility in the Soils of Hardin County, Illinois Average pounds per acre in 2 million pounds of surface soil (about 0 to 6% inches) Soil type No. Soil type Total organic carbon Total nitro- gen Total phos- phorus Total potas- sium Total magne- sium Total calci- um Lime- stone present Lime- stone required Upland Timber Soils 135 Yellow silt loam 12880 1250 840 I 34200 7710 3980 2100 134 Yellow-gray silt loam 15600 1520 870 29150 5510 4390 . 40 864 Yellow fine sandy loam . . . 14180 1300 780 30760 5360 4620 500 198 Stony loam (virgin) 15600 840 480 25040 3420 4300 1520 Swamp and Bottom-land Soils 1323 Red-brown clay loam 32320 3090 1830 41200 11780 6430 2390 1331 Deep gray silt loam 12920 1100 580 26580 4860 5860 660 1361.1 Mixed fine sandy loam. . . 13900 1290 650 29480 4990 4910 840 1380 River sand 11100 520 920 18740 5720 10420 21620 Terrace Soils Gray clay 37160 3280 1260 39220 12560 11860 1020 Gray silt loam on tight clay. 39280 3360 1440 41860 11880 6360 260 By comparing the data in Table 1 with those in Table A in the Appen- dix, the relative supply of the different essential elements of plant food is very easily determined. Thus the surface soil of an acre of the yellow silt loam (the most extensive soil type in Hardin county, covering most of the ordinary hill land) contains only 1250 pounds of total nitrogen, while the 4 Soil Report No. 3 [August, grain crops suggested in Table A would remove from the soil 343 pounds during one rotation; and the total nitrogen in the plowed soil (if 6 2 / t , inches deep) would meet the requirements of only eight such crops of corn as ought to be grown under the average climatic conditions of southern Illi- nois. The ratio of carbon to nitrogen (about 10 to 1) shows that the organic matter is very inactive, and consequently that the liberation of nitrogen will not be rapid. The other upland soils of the county are not much better supplied with nitrogen ; and too great emphasis cannot be laid upon the importance of growing legume crops, such as alfalfa, clover, cow- peas and soybeans, which if infected with the proper nitrogen-fixing bacteria have -free access to the inexhaustible supply of nitrogen in the air. jt On the other hand, there are some difficulties to be met and overcome if the most valuable legume crops are to be grown satisfactorily on these lands. Thus, all of these upland soils are markedly sour and consequently they not only contain no limestone, but require applications of that material to correct the acidity present. The only exception to this is the small area of yellow fine sandy loam near Rosiclare, and even this is strongly acid in the subsurface and sub- Plate 1- Wheat in Pot Cultures; Yellow Silt Loam Soil of Hill Land. soil, the small amount of limestone in the surface soil probably being due to the recent additions of dust blown from the great area of river bed to the east and southwest, which is exposed to the action of the wind when the river is low, occasionally for weeks at a time. Even this soil should receive liberal applications of ground limestone. Results from Pot-Culture Experiments The plant food element which limits the yield of cereal crops on the common upland soil is nitrogen. This fact" is very strikingly illustrated by the results from pot-culture experiments reported in Table 3, and shown photographically in Plate 1. A large quantity of the typical worn hill soil was collected from two different places. Each lot of soil was thoroly mixed and ten 4-gallon jars were filled with it. Ground limestone was added to all except the first and last jars in each set, those two being retained as control or check plots. The elements nitrogen, phosphorus, and. potassium were added singly and in combination, as plainly indicated in Table 3. Hardin County 5 1912] Tabus 3 Crop Yields in Pot-Culture Experiments on Yellow Silt Loam Hill Land Soil Pot No. Soil treatment applied Wheat yields (gramsperpot) Oat yields (gramsperpot) 1 None 3 5 2 Limestone 4 4 3 Limestone, nitrogen . . 26 45 4 Limestone, phosphorus 3 6 S Limestone, potassium ■ 3 5 6 Limestone, nitrogen, phosphorus 34 38 7 Limestone, nitrogen, potassium 33 46 8 Limestone, phosphorus, potassium 2 5 9 Limestone, nitrogen, phosphorus, potassium 34 38 10 ■\T„ri p ■" 3 5 Average yield with nitrogen 32 42 Average yield without nitrogen 3 5 Average gain for nitrogen 29 111 As an average the nitrogen applied produced about eight times as much as the yield secured without the addition of nitrogen. While there are some variations in yield which are due, of course, to differences in the individuality of seed or other uncontrolled cause, yet there is no doubting the plain lesson taught by these actual trials with growing plants. Thus, both the soil analysis and the culture experiment agree in showing that the element nitro- gen myst be provided for the improvement of this soil. The next question is, Where is the farmer to secure this much needed nitrogen? To purchase it in commercial fertilizer would cost too much. In- deed, the cost of the nitrogen in such fertilizers is greater than the value of the increase in crop yields, under average conditions. On the other hand, there is no need whatever to purchase it, because the air contains an inexhaus- tible supply of nitrogen, and under suitable conditions this can be obtained by the farmer direct from the air, not only without cost, but with profit in the getting; for clover, alfalfa, cowpeas and soybeans have pdwer to secure atmospheric nitrogen, provided the soil contains limestone and the proper nitrogen-fixing bacteria; and these crops are worth raising for their own sake. In order to get further information along this line an experiment with pot cultures was conducted for several years, with the results reported in Table 4, the same worn hill soil being used. To three of the pots (Nos. 3, 6 and 9) nitrogen was applied in commercial form, and at an expense amounting to more than the total value of the crops produced. In three other pots (Nos. 2, 11 and 12) a crop of cowpeas was grown during the late sum- mer and fall, and these were turned under before planting wheat or oats. Pots 1 and 8 serve for important comparisons. After the second catch crop of cowpeas had been turned under, the yield from Pot 2 exceeded that from Pot 3 ; and in the subsequent years the le- gume green manures produced, as an average, rather better results than the commercial nitrogen. These experiments confirm those reported in Table 3, in showing the very great need of nitrogen for the improvement of this soil ; and they also show that the nitrogen need not be purchased, but that it can be obtained from the air by growing legume crops and plowing 6 Soil Report No. 3 [August, them under as green manure. Of course, the legume crops could be fed to live stock and the resulting farm manure returned to the land; but this practice is not so good for the soil, altho it may sometimes be more profit- able; and if sufficiently frequent crops of legumes are grown and if the farm manure produced is sufficiently abundant, and is saved and applied with care, this soil can be very markedly improved by live-stock farming, as well as by green manuring. Plate 2. Wheat in Pot Cultures; Yellow Silt Loam Soil of Worn Hill Land. Table 4 — Crop Yields in Pot Cultures, Including Nitrogen-Fixing Green Manure Crops: Yellow Silt Loam Hill Land (Grams per Pot) Pot No. Soil treatment 1903 Wheat 1904 Wheat 1905 Wheat 1906 Wheat 1907 Oats 1 None ■5 4 4 4 6 2 Limestone, legume 10 17 26 19 37 11 Limestone, legume, phosphorus 14 19 20 18 27 12 Limestone, legume, phosphorus, potassium 16 20 21 19 30 3 Limestone, nitrogen 17 14 15 9 28 6 Limestone, nitrogen, phosphorus 26 20 18 18 30 9 Limestone, nitrogen, phosphorus, potassium 31 34 21 20 26 8 Limestone,* phosphorus, potassium 3 3 5 3 7 Results from Field Experiments at Vienna In 1902 a soil experiment field was established on the worn hill land of southern Illinois, near Vienna, in Johnson county; and the results of nine years’ experiments under field conditions are reported in Table 5. This field includes three divisions, or series, with five plots in each series. A three-year rotation of wheat, corn, and cowpeas was begun on this field, but because of local interest this was changed to corn, wheat, and clover. When the clover failed, which was frequent, cowpeas were substituted. During the first three years the entire crop of cowpeas was plowed under, except on Plot 1, as indicated in Table 5. During the second three years all crops were removed; and during the third three-year period the pods of the compeas (small yields not threshed), and all grain were harvested and re- moved, while the pea vines or clover, and the wheat straw and corn stalks were returned to the land (except on Plot 1, from which all crops were re- 1912] Hardin County 7 moved and nothing returned). Thus, the “crop residues” were returned in part during the first period, not at all during the second period, and com- pletely only during the third period ; and the effect of plowing under all crop residues during one rotation upon the crop yields of the next rotation is not yet shown on this field. If we pass over the first three years required to get the rotation and soil treatment underway, we still have the records of six years, during which time 6 crops of corn, 6 crops of wheat, and i crop of clover hay were harvested and weighed. A study of Table. 5 will show that the land treated with ground limestone and some crop residues (Plot 3) produced, during the six years, 74 bushels more corn, 60 bushels more wheat, and i)4 tons more hay than the untreated land. It should be kept in mind that the figures showing increase in crop yields constitute the real data upon which all subsequent computations must be based. The work of the investigator is to conduct the experiment and secure the data; while the farmer and landowner has the right to use any prices he can justify for his locality and conditions, and these prices will vary greatly, not only in different years and seasons, but also in different localities. Thus the average price of corn in southern Illinois is probably 10 cents a bushel higher than in the corn belt, except in an occasional year when southern Illinois may produce an extra good crop and have a surplus to be shipped out. As a rule the farmer is inclined to calculate the value of the increase in crop yields at the prevailing prices; while the computations usually made by the Experiment Station are much more conservative. At current prices for produce, say 60 cents, a bushel for corn, 90 cents for wheat, and $15 a ton for hay, the increase in money value from the use of limestone on the Vienna field would amount to $117, which is $39 per acre for the six years, or $6.50 per acre per annum above the returns for the same crops from the untreated land. By comparing Plots 2 and 3, it will be found that the land treated with limestone produced, during the same six years, 64 bushels more corn, 39 bushels more wheat, and 1.1 tons more harvested hay than the land other- wise treated the same. At the prices mentioned these increases amount to $90 from three acres, or $30 from one acre, which is $5.00 an acre for each year. This is about ten times the necessary average annual expense for ground limestone in permanent systems. Thus, long-continued investiga- tions have shown that 800 pounds per acre is about the average annual loss of limestone. At $1.25 per ton, this would cost 50 cents per acre per annum. These figures indicate a possible gross return of about $to for every $1.00 necessarily invested in ground limestone for the improvement of this soil, which represents by far the most extensive soil type in the seven southernmost counties of Illinois. Some will probably insist that the prices and computations used above are reasonable and fair; and if present prices continue, it is possible that investment in ground limestone may ultimately pay such returns if the seed of the legume crops are harvested and if the full system of manuring with crop residues and catch crops is followed in the best crop rotation; but in' Table 5 we have presented the more con- servative figures. ki- ln order to summarize the results of the nine years’ experiments, the six grain crops from each series and the one crop of clover hay harvested 8 Soil Report No. 3 [August, from the 200 series (in 1907) are reduced to a money basis, in which corn is figured at 35 cents a bushel, oats at 30 cents, wheat at 70 cents, and hay at $6.00 a ton. These low prices are used in order to avoid any possible ex- aggeration of the value of the increase produced by the soil treatment applied. The prices are appreciably below the ten-year averages for Illi- nois, but it should be kept in mind that the increase produced by soil treat- ment is not delivered at the market by that treatment, but only ready . for the harvest; and additional expense is required for harvesting, threshing, baling and storing or marketing. The yields are all given, and anyone can compute the value of the increase at any other prices, if desired. About 9 tons per acre of ground limestone were applied in 1902. The cost of this is figured at $1.25 per ton. This is somewhat above the average cost in southern Illinois. The phosphorus was supplied at the rate of 25 pounds per acre per an- num in 200 pounds of steamed bone meal, applied at the rate of 600 pounds every three years. It is figured at 10 cents a pound for phosphorus, or at $25 a ton for steamed bone. The average cost of steamed bone is now somewhat higher; and where farm manure or green manure is available we advise using raw rock phosphate in place of steamed bone, the raw phos- phate being just as rich in phosphorus and costing in southern Illinois less than $8.00 per ton in carload lots. The potassium was applied at the rate of 42 pounds per acre per annum in 100 pounds of potassium sulfate. The potassium sulfate is figured at $50 per ton, or potassium at 6 cents a pound. As shown in Table 2, this common upland contains, as an average, more than 30,000 pounds of potassium in the plowed soil of an acre (6^3 inches deep), and the subsurface and subsoil are still richer, so that the potassium problem is not one of addition but of liberation; and, if potassium salts are applied at all or temporarily, until more vegetable matter can be grown and plowed under, then we would recommend the use of kainit in larger amounts and at less expense, rather than potassium sulfate, for reasons explained in the Appendix. It should be understood that when these field experiments were begun, we had but very little information concerning the composition or require- ments of Illinois soils. We used steam bone meal and potassium sulfate to find out if the soil needed phosphorus or potassium. It was known that these materials furnish those elements in good form. On many experiment fields established more recently we are now using fine-ground rock phosphate with very good results, and in some cases we are also making trials with kainit. (See Soil Reports Nos. 1 and 2 and Circulars 116, 127, 149, and 157 -') Taking into account the entire period of nine years, it will be seen that, at most conservative prices, the ground limestone has alreadv paid back nearly twice its actual cost, and the equivalent of about one-half of the limestone still remains in the soil for the benefit of future crops.* It is *On the Edgewood experiment field in Effingham county 10 tons per acre of ground limestone were applied in 1902. At the end of ten years the analysis of the soil showed that 8,370 pounds of limestone still remained in the surface stratum, as the average of eight treated plots ; while the acidity of the subsurface of the same plots averaged 2770 pounds less fin terms of limestone required to neutralize it) than the average of eight untreated half plots, and the acidity in the surface soil of the untreated land corresponded to 1070 pounds of limestone required. Thus the total difference at the end of ten years is equivalent to 6.1 tons of calcium carbonate, and the net loss has been 3.9 tons of lime- stone, or 780 pounds per acre oer annum. (These averages are based upon analyses in- volving twenty-four determinations, which were made by Mr. C. F. Ferris, B.S., as part of his work for the degree of Master of Science in Agronomy, 1912.) Hardin County 9 1912 ] Table 5.— Crop Yields per Acre on Vienna Experiment Field, on Common Worn .Hill Hand: Yellow Silt Loam, Unglaciated Soil treatment None (except rotation) Crop residues Crop residues and limestone Crop residues, limestone, phosphorus Residues, limestone, phosphorus, potassium Plot No 101 102 103 104 105 1902 Corn, bu 15.5 13.3 14.9 12.5 19.9 1903 Corn, bu 9.3 5.0 8.3 7.4 11.6 1904 Cowpeas removed turned turned turned turned 190S Wheat, bu 1.3 10.8 18.2 25.6 30.0 1906 Cowpeas removed removed removed removed removed 1907 Corn, bu 16.7 17.8 30.3 37.1 38.1 1908 Wheat, bu 0 0 4.5 8.3 9.8 1909 Cowpeas removed turned turned turned turned 1910 Corn, bu 33.5 35.4 44.7 46.6 58.3 Value of six crops $27.16 $32.59 $50.26 $59.99 $72.63 Increase over Plot 2 $17.67 $27.40 $40 04 Plot No 201 202 203 204 205 1902 Oats, bu 19.1 18.8 19.8 20.0 31.7 1903 Cowpeas removed turned turned turned turned 1904 Wheat, bu 6.7 7.1 10.0 14.8 17.5 1905 Corn, bu 37.5 42.9 61.9 57.2 56.5 1906 Wheat, bu 3.8 5.4 17.9 11.3 15.0 1907 Clover, tons .65 .81 1.92 2.56 2.23 1908 Corn, bu 35.2 35.6 43.9 42.9 50.6 1909 Wheat, bu 4.6 6.8 9.6 12.8 11.3 1910 Clover . . removed turned turned turned turned Value of seven crops $45.65 $51.49 $80.74 $83.63 $91.04 Increase over Plot 2 $29.25 $32.14 $39.55 Plot No 301 302 303 304 305 1902 Cowpeas removed turned turned turned turned 1903 Wheat, bu .4 .6 .7 8.0 11.0 1904 Corn, bu 30.5 35.5 49.1 49.4 44.7 1905 Cowpeas removed removed removed removed removed 1906 Corn, bu 41.2 40.6 48.9 40.9 40.9 1907 Wheat, bu 4.3 6.1 13.0 13.6 15.6 1908 Cowpeas removed turned turned turned turned 1909 Corn, bu 23.0 24.9 31.3 32 6 33.5 1910 Wheat, bu 3.1 8.7 13.7 14.4 14.6 Value of six crops . . . $38.61 $46.13 $64.44 $68.22 $70.53 Increase over Plot 2 . . . . $18.31 $22.09 $24 40 A era^e of three series . . $37.14 $43.40 $65 . 14 $70.61 $78.06 Increase over Plot 2 $21 . 74 $27.21 $34 66 Cost of treatment $11.25 $33.75 $56.25 possible, too, that half the quantity of limestone applied at the beginning would have given nearly or quite as good results, but the information avail- able is not conclusive as to the initial amount of limestone to apply for the most profitable results. In any case the initial application should . be consid- ered as an investment to be added to the value of the land, while the cost of subsequent necessary applications should be calculated in the annual exoense. 10 Soil Report No. 3 [August, On this rolling hill land, the addition of $22.50 worth of steamed bone meal has increased the crop values by only $5.47 in nine years; and the fur- ther addition of $22.50 in potassium sulfate has produced only $7.45 in- crease in the value of the crops harvested, at the prices used for the increase in yields. Whether a much larger use of organic manures will ultimately increase the nitrogen content of the soil to a point where phosphorus can be applied with profit on these hill lands, subject to rather serious surface washing, seems somewhat doubtful ; and, considering the fact that such an increase in decaying organic matter will largely increase the liberation of potassium from the enormous supply contained in the soil, it seems even more doubt- ful if the addition of potassium will ever be advisable in permanent systems of general farming. Both the pot cultures and the field experiments agree in showing that nitrogen is by far the most limiting element and that this can be secured from the air by legume crops where liberal use is made of ground limestone to correct the acidity of the soil; and of course the limestone also furnishes the element calcium, the supply of which in this soil is but little more than one-tenth as great as the supply of potassium, while the combined loss by leaching and cropping is nearly ten times greater with calcium than with po- tassium, as is more fully explained in the Appendix. As plant food, calcium is especially important for such crops as clover. (See Table A in the Appendix.) Results from Field Experiments at Raleigh The Raleigh experiment field, in Saline county, is located on the gently undulating timber land (yellow-gray silt loam), which is also the second most important upland soil type in Hardin county. Six tons per acre of ground limestone were applied to certain plots on the Raleigh field in the fall of 1909; and as an average of the next two years (1910 and 1911) the limestone increased the yields per acre on one set of plots by 3.9 bushels of wheat, by .40 ton of hay (cowpeas or clover), by 14. 1 bushels of oats, and by 13.4- bushels of corn; while on another set of plots the average increases produced by limestone were 4.8 bushels of wheat, 9.3 bushels of oats, and 12.0 bushels of corn. In this second series of experiments the legume crops (except the seed) are plowed under for soil improvement; but no seed was produced either on the cowpeas in 1910 or on the clover in 1911, and consequently the effect of the limestone on the legume crops was not determined in this system. If we accept the average of the two series and compute the effect from these data for the four-year rotation, we find a return of $12.20 from an investment of $7.50 in limestone; and the limestone applied to the soil is sufficient to last for more than to years. These data strongly support those from the Vienna field in showing the positive value and need of limestone in the very beginning of improvement for these acid upland soils of southern Illinois. The work at Raleigh has been carried on for only two years, and the organic manures thus far produced and returned to the soil are too meager to produce results from which trustworthy conclusions can be drawn con- cerning either the nitrogen secured or the phosphorus and potassium liber- ated; but that the addition of fine-ground raw rock phosphate in connec- Hardin County 11 1912] Table 6 Fertility in the Soils of Hardin County, Illinois Average pounds per acre in 4 million pounds of subsurface soil (about 6 % to 20 inches) Soil Total Total I Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- calci- stone stone No. carbon gen | phorus sium I ' sium um present required Upland Timber Soils 135 Y ellow silt loam 9670 1390 1930 71340 19780 7650 8910 134 Yellow-gray silt loam 13600 1500 1820 64320 15000 8060 2780 864 Yellow fine sandy loam . . . 12920 1640 1960 67640 17560 7840 5000 Swamp and Bottom-land Soils 1323 Red-brown clay 9720 loam . 35120 3960 3180 86200 25240 3220 1331 Deep gray silt loam 10480 960 880 55280 11640 11400 1361.1 Mixed fine sandy loam . . . 28460 2580 1220 56860 8960 9860 2000 1380 River sand. . . 18960 760 1840 33640 10640 20080 30760 Terrace Soils 1516 Gray clay Gray silt loam 43920 4160 2080 77200 28200 23240 40 1530 on tight clay 2' 400 2080 1800 88720 34480 13160 2800 Table 7. — Fertility in the Soils of Hardin County, Illinois Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil Total Total Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- calci- stone stone No. carbon gen phorus sium sium um present required U pland Timber Soils 135 Y ellow silt loam 8060 1310 2700 109070 30670 19580 10060 134 Yellow-gray silt loam 10020 1620 2610 94530 25830 12330 13950 864 Y ellow fine sandy loam . . 8400 1500 3240 107400 29580 13320 10080 Swamp and Bottom-land Soils 1323 Red-brown clay loam 35910 4080 4440 130800 36210 14610 4560 1331 Deep gray silt loam 12300 1380 1440 86340 21600 17760 1361.1 Mixed fine sandy loam .. 41550 3990 2370 78180 13590 17100 3000 1380 River sand . • ■ • 24480 660 1740 47160 13080 24960 32880 Terrace Soils 1516 Gray clay ... . 33480 3000 2460 106200 43560 36180 60 1530 Gray silt loam on tight clay . 31200 3420 2880 132660 51120 19980 1500 tion with organic manures (farm manure, green manures or crop residues) will prove profitable on these undulating or gently rolling upland soils is very certain from the results already secured from other experiment fields. (See Soil Reports Nos. 1 and 2, and Circulars 116, 149, and 157.) On the other hand, the first step in the upbuilding of these soils is the liberal 12 Soil Report No. 3 [August, wse of limestone in connection with clover or other legume crops grown in rotation with corn and other grains; and when the legume crops or farm manures are available to plow under in significant amount then is the time to begin the application of phosphate, to be turned under in intimate con- tact with the decaying organic matter. Where used in this way on very similar land at the Ohio Agricultural Experiment Station, as an average of duplicate tests on three different series of plots during a period of fifteen years, every dollar invested in raw phosphate paid back $7.42, counting $7.50 per ton for the phosphate, 35 cents a bushel for corn, 70 cents for wheat, and $6.00 a ton for clover hay; while in a corresponding experiment every dollar invested in acid phosphate (at $15 per ton) paid back $3.69. (See Illinois Circulars 116, 127 and 130 for more details of these valuable Ohio experiments. ) No field experiments have been conducted on the less extensive soil types, but their composition is shown in Tables 2, 6 and 7, and their general char- acteristics and meeds are discussed for each individual type in the following pages. The Subsurface and Subsoil In Tables 6 and 7 are recorded the amounts of plant food per acre in the subsurface (6 ^ to 20 inches) and subsoil (20 to 40 inches), but it should be remembered that these supplies are of little value unless the top soil is kept rich, except that they serve as a source of renewal, even by very slight surface washing, for any element which they contain in great abundance, as is the case with potassium ; and where much surface soil is removed by erosion, as on the rolling hill land, even the supply of phos- phorus is renewed from the substrata in amounts which may equal or ex- ceed the requirements of the crops that are grown where nitrogen is so commonly the limiting element. Among the most important information contained in Tables 6 and 7 is that the upland soils are even more strongly acid in the subsurface and subsoil than in the surface stratum, thus emphasizing the importance of put- ting plenty of limestone in the surface soil to neutralize the acid moisture which rises from the lower strata by capillary action during the periods of partial drouth, which are also critical periods in the life of such plants as clover. In the case of the less rolling upland (vellow-gray silt loam) where surface washing is not marked, the basic elements have been leached out and replaced with acid to such a depth that the subsoil is even more strongly acid than the subsurface, altho this is not the case with the yellow silt loam; and. where very marked recent erosion has occurred, almost unleached subsoil containing limestone is sometimes exposed. Hardin County 13 1912] INDIVIDUAL SOIL TYPES (a) Upland Timber Soils Yellow Silt Loam ( 135 ) This is by far the most common type in the county, occupying 70.5 per- cent of the area, or 120 square miles. The soil was formed from material derived from glacial or alluvial formations, carried by the winds and de- posited at all altitudes. The average depth of this loess or wind-blown ma- terial is not far from ten feet. The residue from the decay of the rocks has been so completely buried that it forms ordinarily no part of the soil. This residual material may be seen in some cuts as a reddish iclay, fre- quently mixed with angular cherty or flinty pebbles. The topography of this type varies from rolling to very hilly and includes some land that should not be cultivated at all or that may be farmed only with the greatest care to avoid loss by erosion. Much of this type has been abandoned agri- +* culturally already, and some of it should never have been cleared of its protecting forests. It frequently occurs that the northern slopes are abrupt, while those toward the south are more gradual and may be cultivated fairly well. In the part of the county in the vicinity of Elizabethtown and Cave-in- Rock the rolling topography is due in part to the many sink-holes formed by the solution of the underlying limestone. These depressions vary in size from about 30 feet to several hundred feet in diameter and perhaps from 10 to 40 feet deep. They drain naturally into underground channels, but in many cases these drainage outlets have been stopped and sinkhole ponds result. About three miles northwest of Cave-in-Rock this obstructed drainage has resulted in the formation of a lake that covers an area of 100 acres or more, varying in extent with the time of year and the amount of rainfall. (The soil area shown as 1361.1 shows the limit of the lake when at its greatest size.) The surface soil of the common hill land, o to 6 2 /z inches, is a light «* brown to yellow silt loam varying with the amount of organic matter, which in turn is dependent to a large extent upon the amount of erosion. Usually the latter color prevails. The organic matter content is very low in this tvpe, much too low for a fertile soil, about 1.1 per cent, as an average, in the surface soil, or only 11 tons per acre. From its yellow color this type is commonly called a clay soil; but it contains from 25 to 30 percent of fine sand, and much the larger part of the remaining 70 to 75 percent is silt, thus rendering it porous and mealy and easily worked ; whereas true clay is plastic or gummy and very difficult to work. The surface soil is usually dis- tinguished from the subsurface by a difference in color due to the still lower organic content of the subsurface soil. The subsurface stratum is somewhat variable in thickness, depending upon the amount of erosion that has taken place, the average being about 8 or 9 inches. In some spots it is practically absent, while in others it is from 10 to 12 inches in thickness. It is a light vellow silt loam, mealy, por- ous, and pulverulent, the phvsical composition being a little finer than in the ^ surface. The average organic matter content is .4 percent, or only 8 tons per acre for 4 million pounds of soil (6^3 to 20 inches). Soil Report No. 3 [August, Plate; 3. Young Grove of Black Locust Trees on Rolling Hill Land in Johnson County, Illinois. (Grown by J. C. B. Heaton.) The subsoil, extending from the subsurface stratum to a depth of 40 inches, is a yellow silt or slightly clayey silt. Gray blotches of unoxidizecl material often occur in the deeper subsoil. This stratum is more compact and not quite so porous as those above it, yet sufficiently pervious to allow water to pass thru it. The variations of this type are produced chiefly by erosion. It represents varying degrees of fertility. In some places very little washing has occurred, in others the surface has been largely removed, while in others the subsoil may be exposed as unproductive yellow “clay points.” Of most importance in the management of this type is preventing much loss by washing. This process has gone on to such an extent that a large percentage of the type has been agriculturally abandoned, and so far not only has nothing been done to reclaim the abandoned land, but very little has been done to prevent further loss on land now under cultivation. Erosion occurs as sheet-washing and gullying. Ordinarily we do not think of sheet- washing as doing very much damage, but it is really the form that does the greatest amount of injury. Gullying results in the absolute ruin of small areas, but sheet washing reduces the productive capacity of large areas to such a point that not only profitable crops cannot be grown, but even the Hardin County IS 1912] Puate 4. Grove of Locust Trees About Twenty-five Years Ol,d on Routing Hied Land in Johnson County, Ieeinois. (Grown by J. C. B. Heaton.) growth of crops large enough to pay for the raising becomes impossible. Every means should be taken to prevent this loss. Steep gullied slopes probably never can be reclaimed with profit for cropping purposes at the present average prices for labor and farm produce. They were originally forested and these forests should never have been en- tirely removed. It was the only thing that made these lands valuable in the first place, and to make them of any future value they should be re- forested. This has been done in a few cases with excellent success. The ac- companying illustrations show such results. The black locust can be used most successfully for this purpose as it is largely independent of the supply 16 Soil Report No. 3 [August, of nitrogenous organic matter in the soil. Where not in forest the steep land should be kept in pasture as much as possible, and if plowed should be cropped for only one or two years and then reseeded to pasture. Live stock is indispensable to farming on this type of soil. Sheet washing on the moderate slopes may be prevented to a great extent by the following methods : ( 1 ) By increasing the organic matter content, thus rendering the soil more porous, and binding the soil particles together. This can be done by adding farm manure, plowing under stubble, straw, cornstalks, and legume crops, such as clover and cowpeas. (2) By deep plowing to increase the absorption of water and diminish the run-off. Ten inches of loose soil will readily absorb 2 inches of rainfall without run-off. Plowing should be done seven to ten inches deep. (3) By contour plowing. Plowing in this state is often done up and down the hill, producing dead furrows that furnish excellent beginnings for , gullies. Even the little depressions between furrows will aid washing. On land subject to serious' washing, plowing should always be done across the slope on the contour, so that water will stand in the furrow without run- ning in either direction. Every furrow will act as an obstruction to the movement of water down the slope, thus diminishing the velocity of the water, facilitating absorption, and diminishing the amount of run-off and the power of the water to do washing. (4) By the use of cover crops to hold the soil during the winter and spring. Rye is a fairly good cover crop to sow in the corn during the late summer or early fall. Wheat, especially when seeded late, is a poor crop to grow on rolling land because it does not usually make sufficient growth to Table 8. — Crop Yields per Acre from Reclaimed Abandoned Hill Hand: Vienna Experiment Field Year Field 1 Field 2 Field 3 Field 4 1906 1907 1908 Corn 20.4 bu. Cowpeas turned Wheat 7.9 bu. Cowpeas turned Wheat 9 6 bu. Clover .77 ton Clover 1.00 ton Corn 33,5 bu. Corn 24.4 bu. Cowpeas turned 1909 1910 1911 Clover .60 ton* Corn 38.6 bu. Corn 37.8 bu. Cowpeas turned Wheat 17 6 bu. Cowpeas turned Wheat 15.6 bu. Wheat 8.8 bu. Clover 1.53 tons Corn 32.8 bu. Average Yields of Crops Grown Corn Wheat Clover 1906-1908 25 1 bu. 8.8 bu. .89 ton 1909-1911 36.4 bu. . 14.0 bu. 1.07 tons *The yield of clover for 1909 is estimated, the weights not having been taken because of a misunderstanding. afford a good protection to the soil during winter. Of course both rye and wheat invite the development of chinch bugs. A mixture of winter vetch, and clover, with a few cowpeas, seeded at the time of the last cultivation of the corn, gives results in favorable seasons. Experiments in methods of preventing soil erosion are being carried on in Johnson county near Vienna on abandoned land purchased in 1906 by the University of Illinois. In addition to the methods above described, two ions per acre of ground limestone are applied every four years. The Hardin County 17 A912] results show that this land may be reclaimed and made to produce fair crops, as is shown in Table 8. These results show that fairly good crops may be grown upon this aban- doned land if proper care is taken to reduce washing, and if use is made of ground limestone and a good crop rotation. The results also indicate that the crop yields tend to increase under this system. (See also Tables 3, 4 and 5.) Alfalfa may well be one of the crops grown in this type of soil. Note the suggested rotation and directions under Yellozv-Gray Silt Loam and Yellozv Fine Sandy Loam. YellouyGray Silt Loam (134) This type occurs only in limited, somewhat isolated areas over the county, usually surrounded by yellow silt loam (135). The type covers 10.5 square miles, or 6.17 percent of the area of the county. It comprises the less roll- ing areas of the upland and furnishes some good agricultural land. The topography varies from slightly undulating to rolling. All of this land may be cultivated but in some places where it grades toward the yellow silt loam care must be taken to prevent washing. Its origin is the same as the yellow silt loam (135). The surface soil, o to 6Y3 inches, is a yellow to yellowish gray silt loam, porous, mealy, and pulverulent. Its good physical condition is due to the considerable percentage of fine sand that it contains. The organic matter content is low, the average being 1.35 percent — but slightly higher than the yellow silt loam. The subsurface stratum, varying from about 8 to 12 inches in thickness, is a yellow to grayish yellow silt loam distinguished from the surface soil by its lighter color. Its physical composition is very much like the surface except that there is less organic matter, only .56 percent. The subsoil from the subsurface to a depth of 40 inches is a compact yellow or grayish yellow silt or clayey silt, plastic when wet. Concretions of iron are found in the subsurface and subsoil in the more nearly level areas. While the type is one of the best in the county, the supply of organic matter should be increased to keep the soil in good physical condition and thus prevent washing. At least 2 tons per acre of ground limestone should be applied, and 4 or 5 tons would be even more profitable for the initial application, after which about 2 tons every four or five years will be sufficient to keep the soil sweet. Legume crops should be grown in a good rotation, such, for exam- ple, as corn, cowpeas, wheat, and clover, on four fields, with alfalfa on a fifth field. After five years the alfalfa field may be broken up and used for the four-year rotation, one of the four fields being seeded to alfalfa for another five-year period. (See also Yellow Fine Sanclv Loam, page 18.) The organic matter and nitrogen should be increased either by using all crops except the wheat for feed and bedding, saving and retaining the manure produced, or by selling only grain or seed and some alfalfa hay and plowing under all other crops and residues. About 1,000 pounds per acre of very finely ground r-ock phosphate should be plowed under with the organic matter every four or five years, and the initial application may well be at least 1 ton per acre. Temporarily some use may well be made of steamed bone meal, as by drilling about 200 pounds 18 Soil Report No. 3 [August, per acre when seeding wheat on land where no adequate provision has been made for the decaying organic matter required to liberate phosphorus from the raw phosphate used in the more profitable permanent systems of soil improvement. In composition this type of soil resembles that of the gray silt loam prairie (330) described in Soil Report No. 1, and the reader’s attention is called to Tables 3, 6 and 7 in that report, showing the composition of the prairie soil and the results obtained from field experiments conducted in that soil at DuBois and Fairfield. The Raleigh experiment field, referred to in the preceding pages, is located in the yellow-gray silt loam, and, tho recently established, is already beginning to show valuable results from proper meth- ods of soil improvement. Yellow Fine Sandy Loam (864) Only a small area of this type is found in the county, amounting to 294 acres. It occurs on the point extending southward in a bend of the Ohio river, thus furnishing a place of deposit for the material picked up by the wind sweeping over the bottom land when exposed at times of low water. The area is small and very rolling so that very little is under cul- tivation. In some counties along the Mississippi river this type occurs in very extensive areas. Where cultivated it should be protected from excessive surface washing, and liberal use should be made of ground limestone and or- ganic matter. The soil is especially adapted to the growing of alfalfa when well inoculated and sweetened with about 5 tons per acre of limestone; but, in order to give the alfalfa a good start, a moderate application of farm manure or 500 to 1000 pounds per acre of acid phosphate (or still better, both manure and acid phosphate) should be plowed under. After the al- falfa is well started it roots very deeply and becomes almost independent of the top soil, except with respect to limestone. Stony Loam (198) This type occurs on the slopes of hills and ridges where erosion has re- moved most of the loess and residual material, to a large extent leaving a mixture of these and stones to constitute the soil. The stones vary from, a few inches to several feet in diameter. It comprises 17.05 square miles, or 10 percent of the entire area. It is of little agricultural value, its only use, aside from growing of forests, being for pasture. Rock Outcrop (199) This can hardly be considered a type of soil but may have some value as a source of limestone for use on acid soils. The outcrop occurs frequently as perpendicular ledges, and the horizontal width is often somewhat exaggerated in order to show the boundary lines on the soil map. (b) Swamp and Bottom-land Soils Rcd-Brozvn Clay Loam (1323) This type comprises the greater amount of the bottom land along the Ohio river, the total area being 3.16 square miles or 1.86 percent of the area of the county. Two large areas occur, one in the southwest and the other Hardin County 19 ‘ 912 ] in the southeast. A few small areas occur at the mouths of some of the small creeks that flow into the Ohio. This type is formed by deposit from the flood waters of the Ohio river and has been found in all of the counties surveyed that border on that river. The topography varies from almost flat to gently undulating, the undu- lations being due to the narrow but elevated ridges and depressions formed by currents during overflow. The drainage is not always good, there being many low, wet places in which the crop may be badly damaged. The surface soil, o to 6^3 inches, is a yellow to reddish brown clay loam, plastic, but granular under proper conditions. Like all clays and clay loams, it will become hard and intractable if worked when wet, due to pud- dling or the breaking down of the granules. This will be restored by the moistening and drying produced by showers or by freezing and thawing. The amount of organic matter varies from 2)4 to 3)4 percent, with an average of about 2^ percent. The physical composition varies somewhat, the heavier phase being near the bluff and on the lower ground, and the lighter or more sandy near the river. The subsurface, 6 2 /$ to 20 inches, is not distinctly separated from either the surface or subsoil. The color gradually becomes lighter with depth, due to the smaller amount of organic matter, which is 1.5 percent in this stratum. The subsoil, 20 to 40 inches, is a yellowish brown clay loam, tough and plastic, yet pervious to water. It varies slightly with the topography, the lower areas having a heavier subsoil. This soil is more difficult to manage than a lighter soil, owing- to the danger of puddling if worked when too wet and to its cloddy character when dry. This type cracks rather badly owing to the property of shrink- age which clay possesses to such a degree. Corn is the chief crop, but where protected from overflow other crops can be grown. The soil is rich in mineral plant food, but legumes should be grown in the rotation where the land does not overflow. Deep Gray Silt Loam (1331) This type is found in some of the wider bottoms of the small streams, mostly near their mouths. It is formed from material washed from the hills. It seems to be an older deposit than the mixed sandy loam (1361.1) and is occasionally a little higher bottom land. Since its deposition the iron has been deoxidized, and as a result the color has been changed from a yellow or brownish to a gray or light drab. The topography is flat to gently undulat- ing. The extent of this type in the county is 768 acres, constituting only .65 percent of the total area of the county. The surface, o to 6^6 inches, is a gray silt loam varying to a yellowish gray silt loam or fine sandy loam. Iron concretions are usually found upon the surface and mixed with the surface and subsurface strata. All of this type contains considerable fine sand, giving it an almost ideal physical com- position. It is very low in oragnic matter, having only about 1 percent. The subsurface, 6^4 to 20 inches, is a gray silt loam, friable, pulverulent, but compact and not very pervious, especially upon the higher and apparently older areas. The subsoil is mostly a gray silt, but varies from this to a gray silty clay, compact, tough and almost impervious, resembling the subsoil of the gray silt loam on tight clay on the more elevated parts of the bottom land 2kj Soil Report No. 3 [August, The type is drained poorly as a rule, and better drainage with the addi- tion of organic matter are the first requirements for improvement, altho it will be necessary to add limestone to get the organic matter by the growing of legumes, because of the acidity of the soil and subsoil. Where protected from overflow phosphorus should also be applied in systems of permanent improvement. Mixed Fine Sandy Loam (1361.1) This type is found along the small stream of the county as bottom land, varying in width from a few rods to a half mile, altho in these wider places the soil may grade toward the deep gray silt loam. The material forming this type has been rather recently washed from the surrounding hills, the finer particles being carried into the Ohio river, while the coarser are de- posited in these bottoms. The topography is flat to gently undulating, the undulations being due to the old system channels and those produced during floods. Natural drain- age is usually good. In some places the type is underlain by gravel. The total area of the type is 8074 acres or 7.4 percent of the entire area of the county. The surface, subsurface and subsoil are practically the same, the chief difference being in the amount of organic matter in some places, altho this does not vary as much as might be supposed. The amount varies from 1 to 1^2 percent in the surface soil. This is one of the best types in the county, producing fair crops of corn, wheat and cowpeas. As a rule this soil is not acid, more or less of the material being almost unweathered, having been recently washed out of deep gullies. Because of the porous character of the soil and subsoil, and the conse- quent deep-feeding range afforded to plant roots, and also because of the liability to overflow, it is very doubtful if any purchased materials should be applied to this kind of land; but legumes should be grown in rotation where conditions permit. River Sand (1380) This type covers about 130 acres along the Ohio river in the southward extension southwest of Rosiclare and is a deposit formed by water and re- worked to some extent by wind. The sand is largely derived from a sand bar beside this area on the north side of the river, this sand bar being ex- posed. during low water. There is very little difference between the different strata of sand ex- cept tkat occasional layers of silt or clay from 2 to 4 inches thick are found in the subsoil. These have been deposited during overflow from the Ohio river. The sand is exceedingly poor in organic matter and nitrogen, altho the ratio between the organic carbon and nitrogen indicates that the small amount of organic matter present is in moderately fresh condition, as might be expected from the formation and age of this river sand. Where it is cultivated, legume crops should be grown in the rotation if practicable. Considering its composition and very porous character, no applications can be advised except nitrogenous organic matter, best secured as a rule by le- gume crops. 1912 ] Hardin County 21 (c) Terrace Soils Gray Clay (1516) This type comprises about 196 acres, mostly in the northeast part of the county. There are two small areas in the southwestern part along small streams. This with the type described below (gray silt loam on tight clay) represents an old fill, or terrace deposit, caused by the silting up of the Ohio and its tributaries and later cutting down thru them by stream erosion to the level of the present bottom land. The topography is flat, with the exception of a few small draws that have been made by streams. The surface, o to 6 2 /z inches, is a gray to dark drab clay, with iron stains, very plastic, and possessing the property of shrinkage to a marked degree. This stratum contains about 3 percent of organic matter. The subsurface and subsoil are composed of a gray* sticky, plastic clay with blotches of yellow. The soil is very difficult to work; it is easily puddled when too wet, and when dry is very cloddy. It granulates under proper conditions of moisture. Its chief value is for permanent pasture or hay, but even for these purposes it is not a good soil; and because of the physical difficulties it is doubtful if any method of enrichment would be profitable; but if so it would be with limestone, organic matter and possibly phosphorus. Gray Silt Loam on Tight Clay (1530) This type is like the gray clay (1516) in that it is part of an old clay ter- race, but in this case a deposit of silt from 7 to 12 inches deep was made upon the tight clay layer. It occurs in the northeastern part of the county along Harris creek and Saline river and along three small creeks in the vi- cinity of Elizabethtown. The total area is 755 acres. It is very flat and poorly drained. While it is a distinct terrace yet part of it overflows during extremely high water. Tile would be of little use because of the almost impervious subsoil. The surface soil, o to 6 2 /$ inches, is a gray silt loam having about 2 percent of organic matter, sometimes with a yellow tinge due to iron.. It varies from a loose pulverulent silt loam to a somewhat sticky clayey silt loam. The subsurface stratum is sometimes represented by a layer of gray silt loam extending to a depth of 12 inches, but often the clay subsoil begins at a depth of 7 inches and continues without any material change to a depth of 40 inches. The subsoil is a gray or yellowish clay, tough, plastic and nearly impervious. The type has a very low value for agricultural purposes. It produces but little corn or wheat, and grass makes but poor growth. Much of it is still covered with timber, and probably this is the best crop that can be grown upon it. If put under cultivation and protected from overflow, it should be treated with ground limestone, and legume crops should be grown in the rotation ; and with long continued cropping phosphorus would need to be supplied, altho in its virgin condition it is fairly rich in that element, as shown in Table 2. 22 Soil Report No. 3 [August, APPENDIX A study of the soil map and the tabular statements concerning crop re- quirements, the plant food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil improvement, and a careful study of the discussion of general prin- ciples and of the descriptions of individual soil types will furnish the most necessary and useful information for the practical improvement and perma- nent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and import- ant soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility of Illinois Soils,” which contains a colored gen- eral survey soil map of the entire state. Other publications of general interest are: Bulletin No. 76, “Alfalfa on Illinois Soils” Bulletin No. 94, “Nitrogen Bacteria and Legumes” Bulletin No. 99, “Soil Treatment for the Lower Illinois Glaciation” Bulletin No. 115, “Soil Improvement for the Worn Hilk Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois” Circular No. no, “Ground Limestone for Acid Soils” Circular No. 127, “Shall we use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, “Some Results of Scientific Soil Treatment” and “Methods and Re- sults of Ten Years’ Soil Investigation in Illinois” ■NOTE. — Information as to where to obtain limestone, phosphate, bone meal, and po- tassium salts, methods of application, etc., will also be found in Circulars no and 149. Soil Survey Methods The detail soil survey of a county consists essentially of indicating on a map the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential : first, careful, well-trained men to do the work ; second, an ac- curate base map upon which to show the results of their work: and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal varia- tions and limits, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will survey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries will match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil map- ping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construction of these maps, while the most trustworthy county map avail- able is used in locating temporarily the streams, roads, and railroads. Since the best of these published maps have seme inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and cor- Hardin County 23 1912] rected if wrongly located. In order to make these verifications and correc- tions, each survey party is provided with an odometer for measuring dis- tances, and a plane table for determining the directions of roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, additional streams, and necessary corrections are placed with proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils being carried in the field for this purpose. A small augur 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the augur 80 inches long is taken by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while dis- tances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be located with, as high a degree of accuracy as can be indicated by pencil on the scale of one inch to the mile. The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type will grade into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, alluvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical or mechanical composition of the different strata composing the soil, as the percentages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. The common soil constituents are indicated in the following outline : Soil, Characteristics Organic Matter Constituents of Soils f Comprising undecomposed and partially decayed 1 vegetable material {' Soil Constituents Inorganic Matter .001 mm. to .03 mm. . .03 mm. to 1. mm. . . . 1. mm. to 32 mm. . . . 32. mm. and over .001 mm* and less *25 millimeters equal 1 inch. Further discussion of these constituents is given in Circular 82. 24 Soil Report No. 3 [August, Groups of Soil Types The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand and silt and a little clay. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and some silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. . Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 15 to 50 percent gravel with much sand and some sift. Gravels — Soils with more than 50 percent of gravel. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no agricultural value. More or less organic matter is found in nearly all of the above classes. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which this is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly im- portant, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but the rate of liberation is governed by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are lime- stone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may also be supplied by green-manure crops and crop residues, such as clover, cow- peas, straw, and cornstalks. The rate of decay of organic matter depends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which represents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly 20 tons of organic matter. But this organic matter consists largely of the J912] Hardin County 25 old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20 tons of old inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent additions of active organic matter, whether in applications of farm manure, in legume crops, or in grass- root sods of old pastures. Probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that with the normal rainfall of Illinois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such com- modity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts of potassium, magnesium, calcium, etc., for the use of the growing crop. As already explained, fresh organic. matter decomposes much more rap- idly than the old humus, which represents the organic* residues most resistant to decay and which consequently have accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and which thus furnish or liberate organic matter and inorganic food for bacteria, which, under such favorable conditions appear to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when incorporated with fresh farm manure ; so that, when used together, two tons of the mixture may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bacterial action is also promoted by the presence of limestone. The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil ; while in old worn soils that are greatly in need of fresh 26 Soil Report No. 3 [August, active organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insuf- ficient; but even these plants (which include only the clovers, peas, beans, and vetches among our common agricultural plants) secure only from the soil six elements (phosphorus, potassium, magnesium, calcium, iron and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a building is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay; and, where the land is properly drained and properly tilled, such crops would frequently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the abso- lute needs of the crops. Crop Requirements The accompanying table shows the requirements of such crops for the five most important plant food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are not known ever to limit the yield of general farm crops grown under normal conditions). Table A. — Plant Food in Wheat, Corn, Oats, and Clover Produce Nitro- gen. pounds Phos- phorus, pounds Potas- sium, pounds Magne- sium, pounds Cal- cium, pounds Kind Amount Wheat, grain SO bu. 71 12 13 4 1 Wheat straw 2 y 2 tons 25 4 45 4 10 Corn, g^ain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs l / 2 ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2 l / 2 tons 31 5 52 7 15 Clover seed 4 bu 7 2 3 1 1 Clover hay . 4 tons 160 20 120 31 117 Total in grain and seed 244* 42 51 16 4 Total in four crops 510* 77 322 68 168 *Tbe->e amounts include the nitrogen contained in the clover seed or hay, which however may be secured from the air. Hardin County 27 1912 ] To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach is as nearly as possible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the ioo-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with limestone, phosphorus, and manure). On the Fairfield experiment field in Wayne county, on the common prairie land of southern Illinois, yields have been obtained in favorable sea- sons as high as 90 bushels per acre of corn, and 3^2 tons of air-dry clover hay. The importance of maintaining a rich surface soil cannot be too strongly emphasized. It is well illustrated by data from the Rothamsted Experiment Station, the oldest in the world. Thus on Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well fertilized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (o to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods oe Liberating Plant. Food Limestone and decaying organic matter are the principal materials the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria which have power to transform the insoluble and unavail- able organic nitrogen into soluble and available nitrate nitrogen. At the same time the products of this decomposition have power to dis- solve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing whatever to the soil, but always leaves the soil poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root devel- opment and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. 28 Soil Report No. 3 [August, Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows : (1) If the soil is acid apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC 0 3 MgC 0 3 ), which contains both calcium and magnesium, and has slightly greater power to cor- rect soil acidity, ton for ton, than the ordinary calcium limestone (CaC 0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years. On strongly acid soils, or in preparing the land for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks) or by using for feed and bedding practically all of the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines : First year, corn (with some winter legume, such as red clover, alsike, sweet clover, or alfalfa, or a mixture, seeded on part of the field at the last cultivation). Second year, oats or barley or wheat (fall or spring) on one part and cowpeas or soybeans where the winter catch crop is plowed 'down late in the spring. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rota- tion. In grain farming, with wheat grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five-year rotation by cutting out either the second or the sixth year; and to a four-year system by omitting the fifth and sixth years. With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover, or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are : Corn, oats, dnd clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat, (4) clover, (5) wheat (and clover), allows legumes to be seeded four times, and alfalfa may be grown on a sixth field for five or six years in the com- Hardin County 29 1912] bination rotation, alternating between two fields every five years, or rotating over all fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute red clover or alsike for the other in about every third rotation, and at the same time to discontinue their use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover-crop (seeded at the last cultivation) in the southern part of the state and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named : 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires V/2 pounds of nitrogen. I bushel of wheat (grain and straw) requires 2 pounds of nitrogen. I ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. I ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops . Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. For grain crops, as wheat, corn, and oats, about two- thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. ( See also discussion of “The Potassium Problem,” on pages below. ) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in considerably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far se- cured shows positively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil improvement. The first application may well be one ton per acre, and subsequently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total ap- plication of from three to five or six tons per acre of raw phosphate con- taining 12 Yz percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in car- load lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phosphate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rotation, but a good methpd is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, 30 Soil Report No. 3 [August, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply of decaying organic matter has been made ade- quate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid) . About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as to furnish available potas- sium and magnesium, and for a few years such use of kainit will no doubt be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for decaying organic matter, since this will necessitate returning to the soil either all produce except the grain (in grain farming) or the manure produced in live-stock farming. (Where hay or straw are sold, manure should be bought.) On soils which are subject to surface washings, including especially the yellow silt loam of the upland timber area, and to some extent the yellow- gray silt loam, and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tend to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently ; but where such lands are farmed under such a system not more than two or three grain crops shoud be grown during a period of ten or twelve years, the land being kept in pasture most of the time ; and where the soil is acid a liberal use of limestone, as top dressings if necessary, and occasional re- seeding with clovers will benefit both the pasture and indirectly the grain crops. Advantage of Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years; but even a partial stand of clover the first time will probably provide a thousand times as many bac- teria for the next clover crop as one could afford to apply in artificial inocu- lation, for a single root-tubercle may contain a niillion bacteria developed from one during the season’s growth. This is only one of several advantages of the second course of the rota- tion over the first course. Thus the mere practice of crop rotation is an ad- vantage, especially in helping to rid the land of insects and foul grass and weeds. ' The deep-rooting clover crop is an advantage to subsequent crops because of that characteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage; and in systems of permanent soil improvement, such as are here advised and illustrated, more limestone and more phosphorus are provided than are needed for the meager or moderate crops produced during the first rotation, and conse- quently the crops in the second rotation have the advantage of such accumu- lated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. Hardin County 31 I the fields. Fortunately, some definite field experiments have already been conducted Pi, ate; 2. Wheat in 1911 on Urbana Fieed CoverXCrops and Crop Residues Plowed Under Fine-Ground Rock Phosphate Applied Average Yieed, 50. 1 Bushees Per Acre Soil Report No. 6 [August, on this most extensive type of soil, both in Knox county and on similar soil in several other counties, as at Urbana in Champaign county, at Sibley in Ford county, and at Bloomington in McLean county. Results of Field Experiments at Urbana A three-year rotation of corn, oats, and clover was begun on the North Farm at the University of Illinois in 1902, on three fields of typical brown silt loam prairie land which, after twenty years or more of pasturing, had grown corn in 1895, 1896, and 1897 (when careful records were kept of the yields produced) and had then been cropped with clover and grass on one field, oats on another, and oats, cowpeas, and corn on the third field, until 1901. As an average of the first three years (1902-1904) phosphorus increased Peate 3. Wheat in 1911 on Urbana Fieed Cover Crops and Farm Manure Peowed Under Average Yieed, 34.2 Bushees Per Acre Knox County 1913] Table 3. — Effect of Phosphorus on Brown Silt Loam at Urbana (Average increase per acre) Rotation Years Corn, bu. Oats, bu. Clover, tons Value of increase 1 Cost of treatment 1 First 1902,-3,-4 8.8 1.9 .68 $ 7.73 $7.50 Second 1905,-6,-7 13.2 11.9 .79 12.93 7.50 Third 1908,-9,-10 18.7 8.4 1.05 15.37 7.17 1 Prices used are 35 cents a bushel for corn, 30 cents for oats, $6 a ton for clover hay, 10 and 3 cents a pound, respectively, for phosphorus in bone meal and in rock phosphate. the crop yields per acre by .68 ton of clover, 8.8 bushels of corn, and 1.9 bushels of oats. During the second three years ( 1905-1907) it produced aver- age increases of .79 ton of clover, 13.2 bushels of corn, and 11.9 bushels of oats. During the third course of the rotation (1908-1910) it produced aver- Plate 4. Wheat in 1911 on Urbana Field Cover Crops and Farm Manure Plowed Under Fine-ground Rock Phosphate Applied Average Yield, 51.8 Bushels Per Acre 10 Soil Report No. 6 [August, age increases of 1.05 tons of clover, 18.7 bushels of corn, and 8.4 bushels of oats. For convenient reference the results are summarized in Table 3, Wheat is grown on the University South Farm in a rotation experiment started more recently. As an average of the four years 1908 to 1911, raw rock phosphate (with no previous application of bone meal) increased the yield of wheat by 10.3 bushels per acre. Here too, as an average of the four years, the phosphorus applied paid back about twice its cost. In the grain system of farming, the yield of wheat in 1911 was 35.2 bushels per acre where cover crops and crop residues are plowed under with- out the use of phosphorus; but where rock phosphate is used the average yield was 50.1 bushels. (See Plates 1 and 2.) In the live-stock system, the yield of wheat in 1911 was 34.2 bushels where manure and cover crops are used without phosphate, and 51.8 bushels, as an average, where rock phosphate is used in addition. (See Plates 3 and 4.) These results emphasize the cumulative effect of permanent systems of soil improvement. Wheat has also been grown on the North Farm during the last three years, and the average increase produced by phosphorus (part in bone meal and part in raw phosphate) has been 12.4 bushels per acre. Results of Experiments on Sibley Field Table 4 gives the results obtained during the past eleven years from the Sibley soil experiment field located in Ford county on the typical brown silt loam prairie of the Illinois corn belt. Previous to 1902 this land had been cropped with corn and oats for many years under a system of tenant farming, and the soil had become somewhat deficient in active organic matter. While phosphorus was the limiting ele- ment of plant food, the supply of nitrogen becoming available annually was but little in excess of the phosphorus, as is well shown by the corn yields for 1903, when phosphorus produced an increase of 8 bushels, nitrogen without phosphorus produced no increase, but nitrogen and phosphorus to- gether increased the yield by 15 bushels. After six years of additional cropping, however, nitrogen appears to have become the most limiting element, the increase in the corn in 1907 having been 9 bushels from nitrogen and only 5 bushels from phosphorus, while both together produced an increase of 33 bushels. By comparing the corn yields for the four years 1902, 1903, 1906, and 1907, it will be seen that the untreated land has apparently grown less productive, whereas on land receiving both phosphorus and nitrogen the yield has appreciably increased, so that in 1907, when the untreated rotated land produced only 34 bushels of corn per acre, a yield of 72 bushels (more than twice as much) was pro- duced where lime, nitrogen, and phosphorus had been applied, altho the two plots produced exactly the same yield (57.3 bushels) in 1902. Even in the unfavorable season of 1910, the yield of the highest-producing plot exceeded that of 1902, while the untreated land produced less than half as much as it produced in 1902. The prolonged drouth of 1911 resulted in almost a failure of the corn crop, but nevertheless the effect of soil treat- ment is seen. Phosphorus appears to have been the first limiting element again in 1909, 1910, and 1911; while the lodging of oats, especially on the Knox County 11 Table 4. — Crop Yields in Soil Experiments, Sibley Field Brown silt loam prairie; early Wisconsin glacation Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Corn | 1906 Corn 1 1907 Oats | 1908 Wheat 1909 Corn 1910 [corn [mi Oats 1 1912 Plot Soil treatment applied Bushels per acre 101 None 57.3 50.4 74.4 29.5 36.7 33.9 25.9 25.3 26.6 20.7 84.4 102 Lime 60.0 54. < 74.7 31.7 39.2 38.9 24.7 28.8 34.0 22.2 85.6 103 Lime, nitrogen . . 60.0 54.3 77.5 32.8 41.7 48.1 36.3 19.0 29.0 22 4 25.3 104 Lime, phosphorus Lime, potassium . 61.3 62.3 92.5 36.3 44.8 43.5 25.6 32.2 52.0 31.6 92.3 105 55.0 49.9 74.4 30.2 37.5 34.9 22.2 23.2 34.2 21.6 83.1 106 Lime, nitrogen, phosphorus . . . 57.3 69.1 88.4 45.2 68.5 72.3 45.6 33.3 55.6 35.3 42.2 107 Lime, nitrogen, potassium. . . . 53 . 3 51.4 75.9 37.7 39.7 51.1 42.2 25.8 46.2 20.1 55.6 108 Lime, phosphorus, 60.9 80.0 39.8 41.5 39.8 27.2 28.5 43.0 31.8 79.7 109 Lime, nitrogen, phos., potas. . . 58.7 65.9 82.5 48.0 69.5 80.1 52.8 35.0 58. o| 35.7 57 2 110 Nitro., phos., potassium . . . . 60.0 60.1 85.0 48.5 63.3 72.3 44.1 30.8 64 *4 j 31.5 54.1 Average Increase: Bushels per Acre For nitrogen -1.7 3.4 .7 6.4 14.1 23.6 19.3 .1 6.4 1.6 -40.1 For phosphorus 1.7 12.1 10.7 9.2 16.5 15.7 6.4 8.1 16.3 12.0 5.4 For potassium -3.0 -2.9 —5.1 2.4 —1.5 1.0 3.0 — .2 2.7 — .6 7.5 For nitro., phos., over phos -4.0 6.8 —4.1 8.9 23.7 28.8 20.0 1.1 3.6 3.7 -50.1 For phos., nitro. over nitro —2.7 14.8 10.9 12.4 26.8 24.2 9.3 14.3 26.6 12.9 16.9 For potas. , nitro. , phos. over nitro. , phos. . . . 1.4 -3.2 —5.9 2.8 1.0 7.8 7.2 1.7 2.4 .4 15.0 Value of Crops per Acre in Eleven Years Plot Soil treatment applied Total value of eleven crops Value of increase 101 102 None $ 172.73 184.75 $ 12.02 103 104 105 Lime, nitrogen Lime, phosphorus Lime, potassium 167.42 214.50 173.22 _ 5.31 41.77 .49 106 107 108 Lime, nitrogen, phosphorus Lime, nitrogen, potassium Lime, phosphorus, potassium 233.15 188.19 200.37 60.42 15.46 27.64 109 110 Lime, nitrogen, phosphorus, potassium Nitrogen, phosphorus, potassium ... . 244.62 233.51 71.89 60.81 Value of Increase per Acre in Eleven Years Cost of increase For nitrogen F or phosphorus F or nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassium, nitrogen, and phosphorus over nitrogen and TihosrihnriK $-17.33 29.75 18.65 65.73 11.47 $ 165.00 27.50 165.00 27.50 27.50 12 Soil Report No. 6 [August, nitrogen plots, in the exceptionally favorable season of 1912, produced very irregular results. In the lower part of Table 4 are shown the total values per acre of the eleven crops from each of the ten different plots, the amounts varying from $167.42 to $244.62; also the value of the increase produced in crop yields above the value of the yields from the untreated land, corn being valued at 35 cents a bushel, oats at 30 cents, and wheat at 70 cents. Phosphorus with- out nitrogen produced $29.75 in addition to the increase by lime; but, with nitrogen, it produced $65.73 above the crop values where only lime and nitrogen were used. The results show that in 25 cases out of 44 the addition of potassium decreased the crop yields. Even under the most fa- vorable conditions, and with no effort to liberate potassium from the soil by adding organic matter, potassium paid back less than half its cost. By comparing Plots 101 and 102, and also 109 and no, it will be seen that the average increase produced by lime was $11.55, or more than $1 an acre a year. Altho this increase may have been above normal on these plots because of the “condition” of the soil at the beginning, it suggests that the time is here when limestone must be applied to some of these brown silt loam soils. While nitrogen produced an appreciable increase, especially when phosphorus was provided, the only conclusion to be drawn, if we are to utilize this fact to advantage, is that the nitrogen must be secured from the air. Results of Experiments on Bloomington Field Space is taken to insert Table 5, giving all of the results thus far obtained from the Bloomington soil experiment field, which is also located on the brown silt loam prairie soil of the Illinois corn belt. The general results of the eleven years’ work on the Bloomington field tell much the same story as those from the Sibley field. The rotations dif- fered by the use of clover and by discontinuing the use of commercial nitro- gen on the Bloomington field after 1905, in consequence of which phosphorus without commercial nitrogen (Plot 104) produced an even larger increase ($89.92) than was produced by phosphorus over nitrogen ($65.73) on the Sibley field (see Plots 103 and 106). It should be stated that a draw runs near Plot no on the Bloomington field, that the crops on that plot are sometimes damaged by overflow or im- perfect drainage, and that Plot 101 occupies the lowest ground on the oppo- site side of the field. In part because of these irregularities and in part be- cause only one small application has been made, no conclusions can be drawn in regard to lime. Otherwise all results reported in Table 5 are considered reliable. They not only furnish much information in themselves but they also offer instructive comparisons with the Sibley field. Wherever nitrogen was provided, either by direct application or by the use of legume crops, the addition of the element phosphorus produced very marked increases, the average yearly increase for the Bloomington field being worth $7.11 an acre. This is $4.61 above the cost of the phosphorus in 200 pounds of steamed bone meal, the form in which it was applied to the Sibley and Bloomington fields. On the other hand, the use of phosphorus without nitro- gen will not maintain the fertility of the soil (see Plots 104 and 106, Sibley field). As the only practical and profitable method of supplying the nitrogen, a liberal use of clover or other legumes is suggested, the legume to be plowed Knox County 13 W3] Tabus 5 Crop Yields in Soil Experiments, Bloomington Field Brown silt loam prairie; early Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 ■Wheat 1905 Clover 1906 Corn 1907 Corn 1908 Oats 1909 Clover 2 1910 Wheat 1911 Corn 1 1912 1 lou | Soil treatment applied Bushels or tons per acre 101 None 30.8 63.9 54.8 30 8 .39 60.8 40.3 46.4 1.56 22.5 55.2 102 Eime 37.0 60.3 60.8 28.8 .58 63.1 35.3 53.6 1.09 22.5 47.9 103 Lime, crop res. 1 .. . . 35.1 59.5 69.8 30.5 1 .46 64.3 36.9 49.4 (.83) 25.6 62.5 104 Lime, phosphorus. . 41.7 73.0 72.7 39.2 1.65 82.1 47.5 63.8 4.21 57.6 74.5 105 Lime, potassium . . . 37.7 56.4 62. 5| 33.2 .51 64.1 36.2 45.3 1 126 21.7 57.8 106 Lime, residues, 1 phosphorus 43.9 77.6 85.3 50.9 3 78.9 45.8 72.5 (1.67) 60.2 86.1 107 Lime, residues, 1 potassium 40.4 58.9 66.4 29.5 .81 64.3 31.0 51.1 (.33) 27.3 58.9 108 Lime, phosphorus, potassium 50.1 74.8 70.3 37.8 2.36 81.4 57.2 59.5 3.27 54.0 79.2 109 Lime, res., 1 phos., 52.7 80.9 90.5 51.9 3 88.4 58.1 64.2 (-42) 60.4 83.4 potassium 110 Res., phosphorus, 52.3 73.1 71.4 51.1 3 78.0 51.4 55.3 (.60) 61.0 78.3 potassium 1 Average Increase: Bushels or Tons per Acre For residues 1.4 3.1 11.4 5.9 -.96 1.3 -1.1 3.7 -1.64 4.4 7.9 For phosphorus 9.5 17.8 14.8 14.4 .41 18.8 18.0 15.1 1.51 33.9 24.0 For potassium 5.8 .2 .3 .7 .25 2.4 4.2 -4.8 -.63 -.6 2.1 For res.,phos.overphos. 2.2 4.6 12.6 11.7 — .65 -3.2 -1.7 8.7 -2.25 2.6 11.6 For phos.,res. over res. 8.8 18.1 15.5 20.4 -1.46 14.6 8.9 23.1 .84 34.6 23.6 For potas., res., phos. over res., phos 8.8 3.3 5.2 1.0 .00 9.5 12.3 -8.3 -1.25 .'2 -2.7 Value of Crops per Acre in Eleven Years O ru Soil treatment applied Total value of eleven crops Value of increase 101 None $167.22 102 Lime 165.52 -$1.70 103 Lime, residues 173.17 5.95 104 Lime, phosphorus 255.44 88.22 105 Lime, potassium 169.66 2.44 106 Lime, residues, phosphorus 251.43 84.21 107 Lime, residues, potassium 170.57 3.26 108 Lime, phosphorus, potassium 256.92 89.70 109 Lime, residues, phosphorus, potassium 254.76 87.54 110 Residues, phosphorus, potassium 236.66 69.44 Value of Increase per Acre in Eleven Years Cost of increase For residues $ 7.65 7 For phosphorus 89.92 $27.50 For residues and phosphorus over phosphorus -4.01 ? For phosphorus and residues over residues For potassium, residues, and phosphorus over residues 78.26 27.50 and phosphorus 3.33 27.50 ‘Commercial nitrogen was used 1902-1905. ®The figures in parentheses mean bushels of seed; the others, tons of hay. ®Clover smothered by previous wheat crop. 14 Soil Report No. 6 [August, under either directly or as manure, preferably in connection with the phos- phorus applied, especially if raw rock phosphate is used. From the soil of the best treated plots, 160 pounds per acre of phos- phorus, as an average, were removed in the eleven crops. This is equal to more than 13 percent of the total phosphorus contained in the surface soil of an acre of the untreated land. In other words, if such crops could be grown for eighty years, they would require as much phosphorus as the total supply in the ordinary plowed soil. The results plainly show, however, that without the addition of phosphorus such crops cannot be grown year after year. Where no phosphorus was applied, the crops removed only 107 pounds of phosphorus in the eleven years, which is equivalent to only 9 percent of the total amount ( 1,200 pounds) in the surface soil at the beginning ( 1902). The total phosphorus applied from 1902 to 1912, as an average of all plots where it was used, amounted to 275. pounds per acre and cost $27.50. This paid back $84.91, or 300 percent on the investment; whereas potassium, used in the same number of tests and at the same cost, paid back only $1.59 per acre in the eleven years, or less than 6 percent of its cost. Are not these results to be expected from the composition of the soil and the requirements of crops? (See Table 2, page 7, and also Table A in the Appendix.) Nitrogen was applied to this field in commercial form only, from 1902 to 1905; but clover was grown in 1906 and 1910, and a catch crop of cow- peas after the clover in 1906. The cowpeas were plowed under on all plots, and the 1910 clover (except the seed) was plowed under on five plots (103, 106, 107, 109, and no). Straw and corn stalks have also been re- turned to these plots in recent years. The effect of returning these residues to the soil is already appreciable (an average increase of 4.4 bushels of wheat in 1911 and 7.9 bushels of corn in 1912) and probably will be more marked on subsequent crops. Indeed, the large crops of corn, oats, and wheat grown on Plots 104 and 108 during the eleven years drew their nitrogen very largely from the natural supply in the organic matter of the soil. The roots and stubble of clover contain no more nitrogen than the entire plant takes from the soil alone, but they decay rapidly in contact with the soil and probably hasten the decomposition of the soil humus and the consequent liberation of the soil nitrogen. But of course there is a limit to the reserve stock of humus and nitrogen remaining in the soil, and the future years will undoubtedly witness a gradually increasing difference between Plots 104 and 106 and between Plots 108 and 109, in the yields of grain crops. In Plate 5 are shown graphically the relative values of the eleven crops for the eight comparable plots, Nos. 102 to T09. The cost of the phosphorus is indicated by that part of the diagram ab'ove the short crossbars. It should be kept in mind that no value is assigned to clover plowed under except as it reappears in the increase of subsequent crops. Plots 106 and 109 are heavily handicapped because of the clover failure on those plots in 1906 and the poor yield of clover seed in 1910, whereas Plots 104 and 108 produced a fair crop in 1906 and a very large crop in 1910. As an average, Plots 106 and 109 are only $3.09 behind Plots 104 and 108 in the value of the eleven crops harvested, and this would have been covered by about V2 bushel more clover seed in 1906 or 1910, or it may be covered by 10 bushels more corn in 1913. The values from Plots T03 and 107 average $4.28 more than the values from Plots 102 and 105. (See also table on last page of cover.) (R stands for residues; P, for phosphorus, and K, for potassium Kalinin. ) Knox County L5 1913 ] 102 103 104 105 106 107 108 109 0 R P K RP RK PK RPK $165.52 $173.17 $255.44 $169.66 $251.43 $170.57 $256.92 $254.76 Plate 5. Crop Values for Eleven Years, Bloomington Experiment Field Results of Field Experiments at Galesburg In Tables 6, 7, and 8 are reported in detail the results obtained from the University of Illinois soil experiment field near Galesburg, on the line be- tween Knox and Warren counties, on the brown silt loam prairie soil of the upper Illinois glaciation. A six-year rotation has been practiced on this field since 1904. During the first six years the order of cropping was corn, com, oats, wheat, followed by two years of clover and timothy. Since then the rotation has been corn, com, oats, clover, wheat, clover. There are only three independent series of plots, so that while corn is grown every year the other crops are harvested only in alternate years, altho clover should be on the field every year, either in the stubble of the oats and wheat or as a regular crop. Each series contains twenty individual fifth-acre plots 2 rods wide and 16 rods long, with half-rod division strips cultivated and cropped between the plots, a quarter-rod border cultivated and cropped surrounding each series, and grass strips about two' rods wide between the series and surround- ing the experiment field. The soil treatment for the individual plots is indicated in Tables 6, 7, and 8. Limestone was applied in small amount ( 1300 pounds per acre) to the first fifteen plots in each series in 1904. No further application was made until the spring oF 1912, when 4 tons per acre was applied to Plots 1 to 15 of Series 16 Soil Report No. 6 [August, Table 6. — Crop Yields in Soil Experiments, Galesburg Field: Series 100 Brown silt loam prairie; upper Illinois glaciation Corn 1904 Corn ^ 1905 Oats 1906 'wheat 1907 Clo- ver 1 | 1908 Timo- thy 1 1909 Corn 1910 Corn 1911 Oats 1912 Plot Soil treatment applied Bushels > or tons per acre 101 102 103 104 105 Lime Residues, lime Manure, lime Cover crop, manure, lime . . . Lime 63.8 67.3 64.7 65.3 74.7 52.5 49.8 48.1 46.5 54.9 53.8 53.6 50.3 46.7 52. 3 34.0 41.4 31.6 32.8 35.1 7-96) 2.59 2.61 2.80 2.04 (3.83) 1.83 1.70 2.05 59.8 72.6 77.6 77.9 66.2 66.5 75.1 81.0 78.9 67.4 53.3 56.9 60.0 70.2 60.8 106 Lime, phosphorus 78.2 66.1 53.9 41.9 3.18 2.58 72.4 79.4 68.6 107 Residues, lime, phosphorus 75.9 63.1 55.0 41.3 (.67) (4.92) 78.0 83.8 65.2 108 Manure, lime, phosphorus.. 72.6 61.1 54.2 37.9 3.18 2.36 74.6 79.8 77.3 109 Cover crop, manure, lime, phosphorus 74.1 60.0 54.2 40.0 3.15 2.33 74.0 79.1 74.4 110 Lime 72.4 58.8 50.5 32.7 2.65 1.74 61.5 59.2 54.5 111 Lime, phosphorus, po- tassium 81.2 72.3 53.9 36.6 3.21 2.42 74.5 81.1 70.9 112 Residues, lime, phosphorus, potassium 82.3 71.0 59.4 41.1 (.58) (5.00) 81.9 83.7 59.5 113 Manure, lime, phosphor- us, potassium 77.1 72 2 52.8 36.1 3.45 2.49 77.6 82.4 74.4 114 Cover crop, manure, lime, phos., potassium 89.4 69.9 54.5 38.7 3.36 2.55 75.9 85.0 70.0 115 Lime 81.2 68.1 62.8 36.8 2.99 2.19 59.4 67.3 53.0 116 Residues 77.1 61.8 57.3 38.2 (1.17) (5.33) 70.6 68.9 52.0 117 Residues, phosphorus 79.4 64.2 60.0 36.2 (1.25) (5.50) 75.0 77.5 66.1 118 Residues, phosphorus, potassium 82.3 70.8 52.0 40.9 (1.38) (4.75) 78.3 78.4 68.1 119 Residues, lime, nitrogen, phos., potassium 87.1 76.3 66.2 46.0 (1.08) (5.00) 74.8 79.3 67.3 120 None 82.9 65.1 65.3 45.8 3.04 2.82 72.7 67.4 70.2 Increase for residues. —2.19 — .89 5.9 4.3 —7.3 Increase for manure 7.7 5.4 6.3 Increase for phosphorus 6.2 10.7 3.4 3.6 .26 .42 1.8 5.7 10.3 Increase for potassium 6.4 8.3 —.9 — 8 .11 — .01 2.8 2.2 —1.7 Increase for nitrogen 4.8 5.5 14.2 5.1 -(,30) (.25) -3.5 .9 —.8 'The figures in parentheses in these columns represent bushels of seed; the others, tons of hay. 300. Thus far no apparent effect has been produced, but further experiment with liberal applications may show results. Plots 1 to 15 in Series 100 and 200 were given 4 tons per acre in the spring of 1913. The “residues” include the straw and com stalks, all clover except the seed, and legume cover crops, such as cowpeas, soybeans, or vetch, seeded in the corn at the last cultivation. They are returned to certain plots to supply nitrogen and organic matter in a system of grain farming. This system was not fully under way on all series until 1911, as may be seen from the lower parts of Tables 6, 7, and 8, so that as yet no conclusions regarding this treat- ment are justified, except that an abundance of organic matter is thus pro- vided. Whether the value of the clover plowed under will ultimately reappear in subsequent yields of grain and seed, must be determined by the further ac- cumulation of data. 1 'Alsike clover promises to yield the better returns in seed, altho in some cases seed has been threshed from both the first and second cuttings of the red clover. It is quite possible that better average results would be secured by regularly removing the first cutting of red clover, with the purpose of threshing it for seed, as well as the second cutting if found Knox County 17 1913 ] Table 7 Crop Yields in Soil Experiments, Galesburg Field: Series 200 Brown silt loam prairie; upper Illinois glaciation Oats 1904 Wheat 1905 [clover 1906 . Timo- thy 1907 Corn 1908 [corn 1 1909 Oats 1910 Clover 1911 Wheat 1912 Plot Soil treatment applied Bushels or tons per acre 201 Lime 57.5 40.5 . 72 2.30 79.8 54.1 48.0 1.39 17.5 202 Residues, lime 55.0 40.0 .63 1.31 78.8 51.9 43.3 21.1 203 Manure, lime 52.5 38.5 .57 2.55 101.3 65.6 50.6 2.64 21.7 204 Cover crop, manure, lime 55. ( 40.2 .63 2.73 102.7 66.8 53.0 2.32 19.6 205 Lime 67.5 42.2 1.22 2.84 86.3 54.4 44.4 2.29 18.2 206 Lime, phosphorus 62.5 41.3 1.36 3.27 99.6 59.1 55.5 2.42 27.3 207 Residues, lime, phos- phorus. . 57.5 42.2 .90 1.79 105.6 49.4 48.6 27.3 208 Manure, lime, phos- phorus 60.0 40.0 .91 3.18 106.6 69.8 58.6 2.30 27.3 209 Cover crop, manure, lime, phos.. 50.0 39.0 .91 3.16 105.8 75.7 60.3 2.03 27.8 210 Lime 57.5 37.5 .69 2.46 84.5 57.8 42.: 1.14 12.2 211 Lime, phosphorus, po- tassium 55.0 38.7 1.31 3.38 95.7 67.0 55.3 2.01 28.2 212 Residues, lime, phos- phorus, potassium . . 65.0 39.3 1.40 2.15 103.3 57.5 53.8 28.3 213 Manure, lime, phos- phorus, potassium.. 65.0 41.5 1.79 3.62 98.1 69.8 58.3 2.55 25.9 214 Cover crop, manure, lime, phos., potas. . . 62.5 40.7 i:si 3.48 102.8 73.3 62.8 2.46 25.3 215 Lime 60.0 35.5 .83 2.33 84.1 58.2 41.6 .98 8.8 216 Residues 72.5 37.0 .82 1.37 87.3 54.8 38.6 11.8 217 Residues, phosphorus . . 57.5 38.7 .85 1.44 98.6 49.6 43.4 22.1 218 Residues, phosphorus, potassium 50.0 40.7 1.51 2.17 99.0 43.0 46.3 28.3 219 Residues, lime, nitro- gen, phos., potas. . . . 57.5 37.7 1.21 1.98 109.6 47.2 57.2 27.3 220 None 55.0 39.5 .71 2.49 88.3 49.5 38.1 1.00 15.6 Increase for residues —3.1 —1.70 0.0 Increase for manure 7 . 7 8.3 2.9 .56 .6 Increase for phosphorus. . . . -3.0 .7 .21 .41 12.0 2.0 7.3 — .17 7.7 Increase for potassium 2.0 — .1 .52 .39 —3.5 1.4 2.0 .09 .8 Increase for nitrogen 7.5 —3.0 — .30 — .19 10.6 4.2 10.9 —1.0 Farm manure is applied to certain plots (see tables) in proportion to their previous average crop yields, that is, as many tons of manure are applied to each plot as there were tons of average air-dry produce removed from the corresponding plots during the previous rotation; but no manure was used until crops had been grown for four years and the data had been thus ac- cumulated from which to compute the proper applications of manure. The live-stock system was not fully under way on all series until 1912 (see lower parts of tables), when the average increase from the manure varied from 3^ bushel of wheat to nearly 17 bushels of corn. On Plots 4, 9, and 14 cover crops are grown as indicated in the tables, but the results thus far secured do not justify advising this practice, as may be seen by comparing these plots with Plots 3, 8, and 13, respectively. advisable. Some splendid seed crops have been secured from the second cutting when the hrst was clipped and left on the land, hut under other seasonal conditions the second crop has been a failure. In such cases, altho the apparent effect is a total loss of the clover crop, at least part of this apparent loss is recovered in subsequent crops of grain. It should never be forgotten that the purpose of this system is to enable the grain farmer to maintain . fertility of his soil, even tho some other system which he may not be prepard to adopt might be more profitable. v 18 Soil Report No. 6 [August, Table 8. — Crop Yields in Soil Experiments, Galesburg Field: Series 300 Brown silt loam prairie; upper Illinois glaciation Tim- othy 1904 Tim- othy 1905 Cornjcornl 1906 1907 I Oats 1908 Wheat 1909 Wheat 1910 Clover 1911 Corn 1912 Plot Soil treatment applied Bushels or tons per acre 301 Lime 1.36 1.54 66.8 75.9 28.6 31.7 16.2 2.17 70.8 302 Residues, lime 1.38 1.59 68.6 77.7 26.6 33.8 19.4 89.6 303 Manure, lime 1.30 1.92 72.0 80.3 28.3 36.3 19.6 2.57 104.3 304 Cover crop, manure, lime 1.38 2.02 75.6 83.1 26.1 40.4 22.3 2.03 103.3 305 Lime 1.20 1.75 70.5 78.3 22.5 36.6 21.2 1.83 92.1 306 Lime, phosphorus 1.21 1.65 69.7 84.4 32.7 40.6 22.2 2.64 98.2 307 Res., lime, phosphorus 1.16 1.55 74.0 84.1 27.5 41.2 24.1 103.2 308 Manure, lime, phos- phorus 1.25 1.63 73.9 86.1 33.9 39.7 21.6 3.25 107.9 309 Cover crop, manure, lime, phosphorus . . . 1.55 2.03 83.9 87.8 28.9 44.9 24.9 3.13 106.0 310 Lime 1.75 2.25 84.3 85.6 31.6 39.8 22.4 2.74 93.0 311 Lime, phosphorus, po- tassium 2.10 2.41 86.9 87.8 32.3 44.3 24.5 3.59 101.9 312 Residues, lime, phos- phorus, potassium.. 1.55 1.91 75.8 81.2 25.9 41.8 23.2 98.4 313 Manure, lime, phos- phorus, potassium. . 1.16 1.53 68.4 77.9 31.3 35.8 23.0 3.28 108.8 314 Cover crop, manure, lime, phos., potas. . . 1.50 1.52 70.6 81.7 27.7 42.0 23.1 3.57 106.9 315 Lime 1.90 1.97 74.1 85.1 30.6 36.8 21.6 2.47 90.6 316 Residues 1.82 1.82 67.7 80.6 26.7 34.2 22 9 82.1 317 Residues, phosphorus. 1.95 2.00 59.1 83.3 31.1 44.9 27.0 99.2 318 Residues, phosphorus, potassium 2.65 2.18 66.8 73.6 25.8 43.3 29.1 113.2 319 Residues, lime, nitro- gen, phos., potas. . . . 4.15 2.37 71.2 84.7 32.7 43.8 24.9 104.1 320 None 1.46 1.56 59.6 72.8 31.3 28.5 15.8 1.46 79.1 Increase for residues —2.46 5.8 Increase for manure .... 16.7 Increase for phosphorus .01 -.05 1.2 5.1 4.8 6.0 2.9 .86 8.6 Increase for potassium .37 .14 1.6 —4.7 — 2.2 -.8 .6 .47 2.9 Increase for nitrogen 1.50 .19 4.4 11.1 6.9 .5 -4.2 -9.1 At the beginning of this experiment this field was all in timothy sod. Series 300 was not broken during the first two years, but ton of raw rock phosphate per acre was applied as top-dressings. This produced practically no effect, — a result to be expected. A ton of phosphate per acre applied to Series 200 produced no effect on the oats seeded on timothy sod in 1904 and but little effect on the wheat which followed in 1905. Beginning with Series ico in 1904, Series 300 in 1906, and Series 200 in 1908, the regular plan has been to apply i l /> tons of raw rock phosphate (375 pounds of phosphorus) per acre every six years before plowing for corn, in addition to the partial appli- cations made as stated above. This plan has been followed essentially, and will be continued until the phosphorus content of the plowed soil is at least doubled, but ultimately the amounts applied for each rotation will be reduced to supply only about as much as is removed in the crops grown, and of course the annual expense for this element will then decrease accordingly. Potassium is applied in the form of potassium sulfate, 100 pounds per acre of the sulfate (containing* 42 pounds of potassium) being used for each year in the rotation. The application is made only in connection with the Knox County 19 1913 ] phosphate in order to ascertain whether its use in this way is profitable, there being no doubt that it would be unprofitable if used alone. In order to help settle the question whether commercial nitrogen could be used with profit, Plot 19 has received nitrogen at the rate of 25 pounds per acre per annum. Nearly the total amount for the first four years was applied in 1904, but since 1907 the applications have been made annually. The nitrogen has been applied in addition to crop residues, phosphorus, and potassium, but without limestone. Table 9. — Galesburg Experiment Field: Financial Statement (Value of increase from three acres) Series 100 Series 200 Series 300 Y ears Corn Oats Grass 1904 Corn Wheat Grass 1905 Oats Clover Corn 1906 Wheat Grass Corn 1907 Clover Corn Oats 1908 1 Grass Corn Wheat 1909 Corn Oats Wheat 1910 Corn Clover Clover 1911 Oats Wheat Corn 1912 Aver- age 1907 to 1912 For residues . . For manure. . . Forphosph’r’s For potassium For nitrogen. . $ 1.33 S.06 12.93 $ 3.93 3.67 .97 $2.70 3.41 4.00 $6 . 77 .14 6.31 $13.14' 2.70 1 7.20 -1.22 3.98 $-5.34> 2. 90' 7.42 -.13 3.32 > 1.13? 3.57* 4.85 2.00 -.90 $23.46 5.2S 2 6.14 4.13 .31 $ -.16 8.16 11.49 1.06 -4.12 $7.31 1.00 1.48 1 One crop only. 2 Two crops only. In Table 9 is given a financial summary of the results thus far secured from the Galesburg field. Three facts are clearly brought out by the data : First . — Commercial nitrogen at 15 cents a pound has never paid its cost, and as the system of providing “home-grown” nitrogen in crop residues has developed, the effect of commercial nitrogen has decreased, so that as an average of the last five years it has paid back only 4 percent of its annual cost. Second. — Potassium, likewise, has never paid its cost, but during the early years, when no adequate provision was made for decaying organic matter, the soluble potassium salt produced a very marked effect, due in part no doubt to the fact that it helped to dissolve and make available the raw phosphate always applied with it. With the subsequent increase in decaying organic matter, the effect of potassium was greatly reduced. As an average of the last six years, potassium costing $7.50 has paid back only $1. Third .— Phosphorus applied in fine-ground natural rock phosphate in part as top-dressing, and with no adequate provision for decaying organic matter, paid only 47 percent on the investment as an average of the first three years. But it should be kept in mind that the word investment is here used in its proper sense, for the phosphorus removed in the increase produced was less than 2 percent of the amount applied, and that removed in the total crops, less than one-third. During the last six years, however, the phosphorus has paid 130 percent on the investment, even tho two-thirds of the application re- mains to positively enrich the soil. The results from the Galesburg experiment field furnish some interest- ing and valuable illustrations of the danger of drawing incorrect conclusions from field-culture experiments conducted for a short time only and without comprehensive knowledge of the factors involved. Thus, the first year the effect of potassium ($5.06) was four times, and that of nitrogen ($12.93) ten times as great as the effect of phosphorus ($1.33) ; whereas in the last 20 Soil Report No. 6 [August, year the effect of phosphorus ($11.49) was eleven times that of potassium ($1.06), while commercial nitrogen applied in addition to the crop residues appears to have been detrimental. These facts only support the following statement quoted on page 208 of Bulletin 123, “The Fertility in Illinois Soils” : “In considering the general subject of culture experiments for determining fertilizer needs, emphasis must be laid on the fact that such experiments should never be accepted as the sole guide in determining future agricultural practice. If the culture experiments and the ultimate chemical analysis of the soil agree in the deficiency of any plant-food element, then the information is conclusive and final ; but if these two sources of information dis- agree, then the culture experiments should be considered as tentative and likely to give way with increasing knowledge and improved methods to the information based on chem- ical analysis, which is absolute.” 1 The Subsurface and Subsoje In Tables 10 and 11 are recorded the amounts of plant food in the sub- surface and the subsoil, but it should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important in- formation contained in these tables is that the most valuable upland timber soil (yellow-gray silt loam) is usually more strongly acid in the subsurface and the subsoil than in the surface, thus emphasizing the importance of having plenty of limestone in the surface soil to neutralize the acid moisture which rises from the lower strata by capillary action during times of partial drouth, which are critical periods in the life of such plants as clover. Thus, while the common brown silt loam prairie soil is practically neutral, the upland timber soil of similar topography is already in need of limestone; and, as already explained, it is much more deficient in phosphorus and nitrogen than is the common prairie soil. 'Taken from “Culture Experiments for Determining Fertilizer Needs,” by C. G. H. in Cyclopedia of American Agriculture, Volume I, page 475. Knox County 21 1913 ] Tab ue 10. — Fertility in the Soils oe Knox County Average pounds per acre in 4 million pounds' of subsurface (about 673 to 20 inches) Soil Total Total Total Total Total Total Lime- Lime- type Soil type organic nitro- phos- potas- magne- cal- stone stone No. carbon gen phorus sium sium cium present requir’d Upland Prairie Soils 526 Brown silt loam 82 720 6 900 1 960 66 060 22 590 22 880 120 520 Black clay loam | 87 220 7 240 2 680 61 960 29 040 41 760 40 528 Brown gray silt loam on i tight clay 39 720 3 320 1 480 | 71 280 22 080 18 360 440 Upland Timber Soils 534 535 532 Y ellow-gray silt loam Yellow silt loam Light gray silt loam on tight clay 16 830 16 900 20 400 2 210 1 870 1 920 1 420 1 610 1 920 6 7550 7 4860 7 4760 18 740 23 140 23 920 14 650 14 340 17 360 2 240 1 300 720 Swamp and Bottom-Land Soils 1326 Deep brown silt loam 81 370 6 390 2 720 73 ISO 21 730 22 470 90 1301 Deep peat 511 440 38 420 2 480 3 200 14 260 1 362 920 777 780 1303 Shallow peat on clay 238 180 22 180 4 100 23 900 20 740 j 57 100 31 140 'In 2 million pounds of peat (1301 and 1303). Table U.— Fertility in the Soils oe Knox County Average pounds per acre in 6 million pounds' of subsoil (about 20 to 40 inches) Soil Total Total Total Total Total Total Lime- Lime type Soil type organic nitro- phos- potas- magne- cal- stone stone No. carbon gen phorus sium sium cium 1 present requir'd Upland Prairie Soils 526 Brown silt loam 35 160 3 630 2 490 99 890 47 110 35 510 250 520 Black clay loam 25 410 2 490 4 050 100 200 51 690 58 290 19 290 528 Brown-gray silt loam on tight clay 39 000 3 300 2 820 104 820 52 980 32 340 300 Upland Timber Soils 534 535 532 Yellow-gray silt loam.. Yellow silt loam Light gray silt loam on tight clay 16 040 17 570 28 080 2 580 2 150 2 460 3 110 2 780 3 720 101 100 108 580 112 440 47 980 44 440 48 600 30 480 28 940 34 920 rarely 1960 often 720 Swamp and Bottom-Land Soils 1326 Deep brown silt I loam 51 080 4 180 3 520 110 860 37 740 29 500 140 1301 Deep peat 608 520 1 45 420 4 980 7 470 j 22 380 592 020 1287 750 1303 Shallow peat on clay 174 420 | 10 440 6 720 93 540 69 180 384 540 724 020 'In 3 million pounds of deep peat (1301). Soil Ricport No. 6 [ August , INDIVIDUAL, SOIL TYPES (a) Upland Prairie; Soils The soils of this class comprise 411.37 square miles, or 57 percent of the entire county. They are usually dark in color owing to their large organic- matter content. The accumulation of organic matter in the prairie soils is due to the growth of prairie grasses that once covered them, and whose network of roots was protected from complete decay by imperfect aeration due to the covering of fine soil material and the moisture it contained. On the native prairies the tops of these grasses were usually burned or became almost completely de- cayed. From a sample of virgin sod of “blue stem,” one of the most common prairie grasses, it has been determined that an acre of this soil to a depth of 7 inches contained 13^4 tons of roots. Many of these roots died each year and by partial decay formed the humus of these dark prairie soils. In upland forests no such quantity of roots is found in the soil. The vegetable material consists of leaves and twigs, which fall upon the surface and either are burned by forest fires or undergo almost complete decay. There is very little chance for these to become mixed with the soil. As a result the organic-matter con- tent has been lowered by the growth of forests until in some parts of the state a low condition of apparent equilibrium has been reached. Broivn Silt Loam (526 or 226) This is the most important as well as the most extensive type of soil in the county. It covers an area of 402.6 square miles (257,664 acres), or 55.87 percent of the entire county. This type is generally sufficiently rolling for fair natural surface drain- age, altho tile drainage is often needed and there are some exceptions where the land is so flat as to require artificial surface drainage. Some few areas along streams are so rolling that in order to prevent washing they should be cropped only with the utmost care. Altho the brown silt loam is normally a prairie soil, in some limited areas forests have recently extended over the dark soil. These forests consist quite largely of black walnut, with such other trees as wild cherry, hackberry, ash, hard maple, and elm. A black-walnut soil is recognized gen- erally by farmers as being one of the best timber soils. As a rule it still con- tains a large amount of the organic matter that accumulated from the prairie grasses. The surface soil, o to 6^3 inches, is a brown silt loam, varying from it yellowish brown on the more rolling areas to a dark brown or black on the more nearly level or originally poorly-drained areas. The physical composi- tion varies to some extent, but is normally a silt loam containing from 70 to 85 percent of the different grades of silt together with some sand and clay. The amount of clay usually varies from 8 to 12 percent; it increases as the type approaches the black clay loam (520) and becomes greatest in the poorly- drained level areas. The amount of sand varies from 7 to 15 percent and increases as the bottom land of the large streams is approached. The organic-matter content varies from 3.8 to 7.25 percent in the sur- face soil, or from 38 to 72.5 tons per acre,— about 56 tons as an average. Where this type passes into the brown-gray silt loam on tight clay (528) or Knox County 23 1913 ] into the yellow-gray silt loam (534), the percentage of organic matter be- comes lower, but where it passes into the black clay loam it becomes higher. The natural subsurface is represented by a stratum varying from 5 to 16 inches in thickness, being thinner on the more rolling areas and thicker on the level areas. Its physical composition varies in the same way as that of the surface soil, but it usually contains a slightly larger amount of clay. Locally it may become quite heavy, as where the type grades into black clay loam. In color it varies from a dark brown or almost black to a light brown or yellow- ish brown, but as a rule it becomes lighter with depth and passes gradually into the yellow subsoil. The color is due to the presence of organic matter and to the oxidation of the iron. The organic-matter content averages 3.5 percent. The natural subsoil begins 12 to 23 inches beneath the surface and extends to an indefinite depth, but it is usually sampled to 40 inches. It varies from a yellow to a drabbish-yellow clayey silt. In the level or nearly level areas it is of a drab color mottled with yellow blotches, while in the more rolling areas better drainage has allowed higher oxidation of the iron to take place, giving the yellow to brownish-yellow color. The upper 8 to 12 inches of the subsoil usually contains more clay than the lower part, the coarser material consisting of coarse silt or fine sand. The subsoil contains about 1 percent of organic matter, and is generally pervious to water, permitting good under- drainage. While most of this type is in fair physical condition, yet the continuous growing of corn, or com and oats, with the burning of the corn stalks and possibly the oat stubble is reducing the organic-matter content and destroying the tilth. The soil is becoming more difficult to work ; it runs together more ; and aeration, granulation, absorption, and moisture movement are interfered with. This condition of poor tilth is becoming very serious on many farms and is one of the factors that limit crop yields. The remedy is to increase the organic-matter content by plowing under crop residues, such as corn stalks, straw, clover, etc., instead of selling them from the farm or burning them, as is often done at present. The stalks should be thoroly cut up with a sharp disk or stalk cutter and turned under. Likewise the straw should be put back on the land in some practical way, either directly or in the form of manure. Clover should be one of the crops grown in the rotation, and it should be plowed under directly or as manure instead of being sold as hay, except where manure can be brought back. The addition of fresh organic matter is of even greater importance, be- cause of its nitrogen content and because of its power as it decays to liberate potassium from the inexhaustible supply in the soil and phosphorus from the phosphate contained in or applied to the soil. For permanent profitable systems of farming, phosphorus should be ap- plied liberally, and sufficient organic matter should be provided to furnish nitrogen. On the ordinary brown silt loam, limestone is already becoming deficient, but this is not always the case on the heavier phase, which is usually found near draws or in low-lying areas. In live-stock farming an application of two tons of limestone and one-half ton of fine-ground rock phosphate per acre every four years, with the return to the soil of all manure made from a rotation of corn, corn, oats, and clover, will maintain the fertility of this type, altho heavier applications of phosphate may well be made during the first two or three rotations. If grain farming is practiced, the rotation may be 24 Soil Report No. 6 [August, wheat, corn, oats, and clover, with an extra seeding of clover as a cover crop in the wheat, to be plowed under late in the fall or the following spring for corn ; and most of the crop residues, with all the clover except the seed, should also be plowed under. In either system alfalfa may be grown on a fifth field and moved every five years, the hay being fed or sold. (For results of field experiments on the brown silt loam prairie, see Tables 3 to 9.) Black Clay Loam (520) This type of soil represents the flat prairie (the naturally poorly-drained areas of the upper Illinois glaciation) and is sometimes called “gumbo” be- cause of its sticky character. Its formation in these places is due to the accumulation of organic matter and to the washing in of clay and fine silt from the slightly higher adjoining lands. This type is not extensive; it occupies only 8.31 square miles (5,318 acres), or 1.15 percent of the entire area of the county. In topography it is so flat that proper drainage is one of the most difficult problems in its management. The surface stratum is a black, granular clay loam with 7 to 8V2 percent of organic matter, or an average of 78 tons per acre. The wet condition of the soil has allowed a greater accumulation of organic matter in this than in any other type of upland soil in the county. The property of granulation is important to all soils, but it is especially so to heavy ones or those containing considerable clay, since it is by granula- tion that the soil is kept mellow and rendered pervious to air and water. If the granules are destroyed by puddling (as by the tramping of stock while the ground is wet), they will be formed again by freezing and thawing or by wetting and drying. These natural agencies produce “slacking,” as the process is usually termed. If, however, the organic-matter or lime content becomes low, this tendency to granulate grows less and the soil becomes more difficult to work. The subsurface stratum extends to a depth of 10 to 16 inches below the surface stratum. It differs from the surface in color, becoming lighter with depth, the lower part of the stratum passing into a drab or yellowish silty clay, and it also contains a higher percentage of clay. It is quite pervious to water, due to jointing or checking from shrinkage in times of drouth. The amount of organic matter varies from 3 to 4 percent, with an average of 3.75 percent. The subsoil is usually a drab or dull yellow silty clay but locally it may be a yellow or clayey silt. As a rule the iron is not highly oxidized because of poor drainage and lack of aeration. The subsoil is checked and jointed, making it pervious to water and consequently easy to drain. This type presents some variations. Here as elsewhere the boundary lines between different soil types are not always distinct, but types frequently pass from one to the other very gradually, thus giving an intermediate zone of greater or less width. Gradations between brown silt loam (526) and black clay loam (520) are very likely to occur since they are usually adjoining types. This gives a lighter phase of the black clay loam, with a smaller organic- matter content than the average, and a heavier phase of the brown silt loam, with a larger amount of organic matter than usual. Drainage is the first requirement for this type, and because of its pervious- ness it underdrains well. Keeping the soil in good physical condition is very essential, and thoro drainage helps to do this to a great extent. As the organic matter is destroyed by cultivation and nitrification and as the lime- Knox County 25 1913 ] stone is removed by cropping and leaching, the physical condition of the soil becomes poorer, and consequently it becomes more difficult to work. Both or- ganic matter and lime tend to develop granulation. The former should be maintained by turning under manure, clover, and crop residues, such as corn- stalks and straw, instead of burning them as is so commonly practiced. Ground limestone should be applied when needed to keep the soil sweet. While this type of soil is one of the best in the state, yet the clay and humus contained in it give it the property of shrinkage and expansion to such a degree as to be somewhat objectionable at times, especially during drouth. When the soil is wet these constituents expand, and when the moist- ure evaporates or is used by crops, the soil shrinks. The result is the forma- tion of cracks up to two inches or more in width and extending with lessening width a foot or more in depth. These cracks permit the excessive loss of moisture from the surface, subsurface, and subsoil. They also sometimes “block out” the hills of com, tearing the roots and doing considerable dam- age to the crop. While cracking may not be prevented entirely, yet good tilth with a soil mulch will do much toward that end. This type is well supplied with plant food, which is usually liberated with sufficient rapidity by a good rotation and the addition of moderate amounts of organic matter. The amount of organic matter added must be increased, of course, with continued farming until the nitrogen supplied is equal to that re- moved. While no marked profit is to be expected from the addition of phos- phorus, it is likely to pay its cost in the second or third rotation, and even by maintaining the productive power of the land the capital invested is pro- tected. This soil is rich in magnesium and calcium, and the subsoil usually contains plenty of carbonates. With continued cropping and leaching, the ad- dition of limestone will be necessary. (No field experiments have been con- ducted as yet on this type of soil.) Broivn-Gray Silt Loam on Tight Clay (528) This type occupies only .46 square mile (295 acres), or only .06 percent of the area of the county. It occurs almost entirely in areas intermediate between the prairie brown silt loam (526) and the timber yellow-gray silt loam (5.34). In topography it is usually flat. The surface soil, o to 6 2 /z inches, is a light brown to a grayish-brown silt loam, containing some fine sand and coarse silt that gives it a peculiar mealy “feel.” The organic matter varies from 3*4 to 4 percent according to the relation of this type to other types, being greater where it approaches brown silt loam and less where it passes into yellow-gray silt loam (534). The subsurface is represented by a stratum of silt loam 10 to 12 inches thick, which varies in color from brown to gray, usually from the upper to the lower parts of the stratum. It differs from the surface in containing less organic matter, the average percentage being but 1.7. The subsoil is a yellowish clay, beginning 16 to 18 inches beneath the surface. This clay stratum is not so nearly impervious as that of the cor- responding type in southern Illinois. This type should be drained where necessary. Care should be taken to increase the nitrogen, and the organic-matter content by proper rotation and by turning under crop residues, clover, or farm manure. Phosphorus should be used liberally in connection with the decaying organic matter, as on the brown silt loam, and limestone should also be applied at the rate of 2 to 3 tons per acre every four to six years. Soil Report No. 6 [August, 26 (b) Upland Tim3Lr Soils Y elloiv-Gray Silt Loam (534 or 234) This type occurs in the outer timber belts along the streams and covers 104.44 square miles (66,842 acres), or 14^2 percent of the entire county. In topography it is sufficiently rolling for good surface drainage without much tendency to wash if proper care is taken. The surface soil, o to 6^3 inches, is a gray to yellowish-gray silt loam, incoherent and mealy, but not granular. The amount of organic matter aver- ages about 2.2 percent, or 22 tons per acre. The subsurface stratum varies from' 3 to 10 inches in thickness. The greatest variation is due to topography, the thinner subsurface being on the more rolling land. It is a silt loam, gray, grayish-yellow, or yellow in color, somewhat mealy but becoming more coherent and clayey with depth, and con- taining only .72 percent of organic matter. " The subsoil is a yellow or grayish-yellow mottled clayey silt or silty clay, somewhat plastic when wet but friable when moist, and pervious to water. This type is quite variable in texture because of the fact that it grades into so many different types, the transition zone between two types showing a likeness to each. Agriculturally, the yellow-gray silt loam in Knox county is second in im- portance, but with the improvements easily possible its value per acre may become equal to that of the brown silt loam. In the management of this type, one of the first essentials is the maintenance or increase of the organic matter in order to give better tilth, to supply nitrogen and liberate mineral plant food, to prevent running together, and in some of the more rolling phases to prevent washing. Another essential is the application of ground limestone, especially in order that clover, alfalfa, and other legumes may be grown more successfully. Liberal use should also be made of phosphorus, since in the surface stratum of this type there is less than 900 pounds to an acre. (See Table 2, page 5.) For definite results from the' most practical field experiments upon typical yellow-gray silt loam, we must go down into “Egypt,” where the people of Saline county, especially those in the vicinity of Raleigh and Galatia, have provided the University with a very suitable tract of this type of soil for a permanent experiment field. There, as an average of triplicate tests each year, the yield of corn on untreated land was 25.3 bushels in 1910, 23.6 bushels in 1911, and 22 bushels in 1912; while the corresponding averages from land treated with heavy applications of limestone and a limited amount of organic manures were 41.4 bushels in 1910, 41.3 bushels in 1911, and 50.1 bushels in 1912, the corn being grown on a different series of plots every year in a four- year rotation of wheat, corn, oats, and clover. About the same proportionate increases were produced in wheat and hay, and the effect on oats was also marked. Owing to the low supply of organic matter and limestone, phosphorus produced no benefit, as an average, during the first two years, but with in- creasing supplies of organic matter the effect of phosphorus is seen in the crops of 1912 and 1913. Of course, a single four-year rotation cannot be practiced in less than four years, and the full benefit of the system of rotation and soil treatment is not to be expected before .the third or fourth four-year period. Knox County 1913] While limestone is the material first needed for the economic improve- ment of the more acid soil of southern Illinois, with organic manures and phosphorus to follow in order, the less acid soils of the central and northern parts of the state are frequently most deficient, relatively, in phosphorus and organic matter. Table 12 shows in detail eleven years’ results secured from the Antioch soil experiment field located in Lake county on the yellow-gray silt loam of the late Wisconsin glaciation. In acidity, this type in Knox county is inter- mediate between the similar soils in Saline and Lake counties, but no ex- periment field has been conducted on this important soil type in the upper Illinois glaciation. The Antioch field was started in order to learn as quickly as possible just what effect would be produced by the addition of nitrogen, phosphorus, and potassium, singly and in combination. These elements have all been added in commercial form. Only a small amount of lime was applied at the beginning, and with the abnormality of Plot 1 and with an abundance of limestone in the subsoil (a common condition in the late Wisconsin glaciation), no con- clusions can be drawn regarding the effect of lime. As an average of 44 tests (4 each year for 11 years), liberal applications of commercial nitrogen produced a slight decrease in crop values, phosphorus paid back 200 percent of its cost, while each dollar invested in potassium brought back only 34 cents (a net loss of 66 percent). Thus, while the detailed data show great variation, owing both to some irregularity of soil and to some very abnormal seasons, with three almost complete crop failures (1904, 1907, and 1910), yet the general summary strongly confirms the analytical data in showing the need of applying phosphorus and the profit from its use, and the loss in adding potassium. In most cases commercial nitrogen damaged the small grains by causing the crop to lodge; but when- ever a corn yield of 40 bushels or more was secured where phosphorus had been applied either alone or with potassium, then the addition of nitrogen pro- duced an increase. From a comparison of the results from the Sibley and the Bloomington fields, we must conclude that better yields are to be secured by providing nitrogen by means of legume crops grown in the rotation rather than by the use of commercial nitrogen, which is evidently too readily avail- able. causing too' rapid growth and consequent weakness of straw ; and of course the atmosphere is the most economic source of nitrogen where that element is needed for soil improvement in general farming. (See Appendix for detailed discussion of “Permanent Soil Improvement.”) Yellow Silt Loam (535 or 235) This type covers about 133.71 square miles (85,574 acres), or 18.56 percent of the entire county. It occurs as the hilly and badly eroded lands on the inner timber belts along streams, usually only in narrow, irregular strips with arms extending up the small streams. In topography it is very rolling and so badly broken that as a rule it should not be cultivated because of the danger of injury from washing. The surface soil, ‘o to 6% inches, is a yellow or grayish-yellow mealy silt loam. It varies a great deal because of recent washing; in some places the real subsoil may be exposed. The amount of organic matter varies from 1.5 to 3 percent depending upon the extent of the washing, but it averages about 2.2 percent, or 22 tons per acre. 28 Soil Report No. 6 [August, Table 12. — Crop Yields in Soil Experiments, Antioch Field Yellow-gray silt loam, undulating timber- land; late Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Corn 1906 Corn 1907 Oats 1908 Wheat 1909 Corn 1910 Corn 1911 Oats 1912 Plot Soil treatment applied Bushels per acre 101 None 1 1 44.8 36.6 17.8 1 18.5 35.9 12.4 I 65.6 12.2 I 5.2 34.4 21.3 102 Lime ... 45.1 38.9 12.8 10.3 31.5 9.5 | 61.6 11.7 3.0 24.6 17.5 103 Lime, nitrogen. . . 46.3 40.8 2.8 17.8 37.8 6.4| 60.3 13.0 L4 10.4 24.4 104 Lime, phosphorus 50.1 53.6 12.5 35.8 57.4 13.4 70.9 23.3 6.8 37.4 49.1 105 Lime, potassium . 48.2 50.2 9'7| 21.7 34.9 12.9 62.5 13.5 4.6 20.4 18.8 106 Lime, nitro., phos. 56.6 62.7 1 15.9 15.2 59.3 20.9 I 49.1 1 33.8 6.0 37.0 46.9 107 Lime,nitro.,potas. 52.1 54.9 10.3 11.8 39.0 11.1 52.6, 21.0 1.6 7.0 16.9 108 Lime, phos., potas. 60.7 66.0 >9.7 28.7 59.1 18.3 59-4 26.2 3.2 42.2 35.9 109 Lime, nitro., phos. potas 61.2 69.1 31.9 18.0 65.9 31.4 51.9 30.5 3.0 44.2 31.9 110 Nitro., phos., potas. 59. 7| 71.8 37 * 2 | 16.3 66.3 28.8 55.9 34.5 4.0 49.0 38.1 Average Increase: Bushels per Acre For nitrogen 3.0 4.7 1.6 -8.4 4.8 3.9 -10.1 5.9 -1.4 -6.5 -.3 For phosphorus 9.2 16.7 11.1 9.0 24.6 11.0 -1.4 13.7 2.1 24.6 21.6 For potassium For nitro., phos. over 6.0 11.0 6.9 .3 3.2 5.9 -3.9 2.3 -1.2 1.1 -8.6 phos For phos., nitro. over 6.5 9.1 3.4 -20.6 1.9 7.5 -21.8 10.5 -.8 -.4 2.2 nitro For potas., nitro., phos. 10.3 21.9 13.1 —2.6 21.5 14.5 -11.2 20.8 4.6 26.6 22.5 over nitro., phos 4.6 6.4 16.0 2.8 6.6 10.5 2.8 -3.3 -3.0 7.2 -15.0 Value of Crops per Acre in Eleven Years Plot Soil treatment applied I Total value of eleven crops Value of increase O O None $112.16 96.38 $-15.78 103 104 105 Lime, nitrogen Lime, phosphorus • Lime, potassium 97.89 157.67 111.86 —14.27 45.51 -.30 106 107 108 Lime, nitrogen, phosphorus Lime, nitrogen, potassium Lime, phosphorus, potassium 152.75 104.89 160.25 40.59 7 27 48^09 109 110 L,ime nitrogen, phosphorus, potassium. ..... 164.83 172.78 52.67 60.62 Nitrogen, phosphorus, potassium I Value of Increase per Acre in Eleven Years Cost of increase For n For p For n For p For p litrogen •hosphorus. ■ $1.51 61.29 —4.92 54.86 12.08 $165.00 27.50 165.00 27.50 27.50 itrogen and phosphorus over phosphorus hosphorus and nitrogen over nitrogen otassium, nitrogen, and phosphorus over nitrogen and phosphorus ’Plot 101, the check plot, is the lowest ground but it is well drained and is appre- ciably better land than the rest of the field. Plot 102 is a more trustworthy check plot. Knox County 29 1913] The subsurface varies from o to 12 inches in thickness on account of the removal of part or all of the surface and subsurface by washing. The subsoil is a compact yellow clayey silt which in some places may con- sist of glacial drift brought near the surface by erosion. In the management of this type, the most important thing is to prevent general surface washing and gullying. If it is cropped at all, a rotation should be practiced that will require a cultivated crop as little as possible and allow pasture and meadow most of the time. If tilled, the land should be plowed deeply, and contours should be followed as nearly as possibly both in plowing and in planting. Furrows should not be made extending up and down the slope, and the land should be cultivated in the same direction in which it is plowed. Every means should be employed to maintain and to in- crease the organic-matter content in order to supply nitrogen and to help hold the soil and keep it in good physical condition so that it will absorb a large amount of water and thus diminish the run-off. (See Circular 119.) Additional treatment recommended is the liberal use of ground lime- stone. This is advised only where surface erosion has not occurred to too great an extent, and chiefly for such crops as clover and alfalfa, which can often be produced successfully with plenty of limestone (5 tons per acre), thoro inoculation, and about 10 tons of farm manure to give the young alfalfa a good start, after which its extensive root system makes the plant almost independent of the surface soil, except for limestone. An initial application of 500 pounds per acre of steamed bone meal or acid phosphate is often help- ful in starting alfalfa, especially where manure is not available. Light Gray Silt Loam on Tight Clay (532) Only two very small areas of this type, aggregating but 12 acres, are shown on the map. Many others occur, but they are too small to be repre- sented on a map of this scale. The surface soil is a white or light gray silt loam, incoherent, mealy, and porous. Spherical iron concretions are usually present. The organic-matter content is low, amounting to only about 2.2 percent, or 22 tons per acre. The subsurface is a light gray silt extending to a depth of 14 to 18 inches, becoming more clayey with depth and containing only .7 percent of organic matter. The subsoil is a tight, compact, plastic, clayey silt, yellow with gray mot- tlings. Besides being deficient in organic matter, this type is lacking in limestone and is consequently in poor physical condition. It runs together badly and, owing to the strong capillarity in the surface and subsurface strata, it does not hold moisture well. In the management of this soil, ground limestone should be used liberally, rock phosphate should be added, and the organic- matter content increased in every practical way. Deep-rooting crops, such as red, mammoth, or sweet clover, would loosen the tight clay subsoil as well as supply the soil with organic matter and nitrogen. Crop residues or farm manure should be plowed under to bring the soil into better tilth. 30 Soil Report No. 6 [August, (c) Swamp and Bottom-Land Soils Deep Brown Silt Loam (1326) The bottom-land soil is derived from material washed from the upland, and must therefore have some relation to the upland soils. It differs in being more variable in physical composition than any single upland type, and the brown color extends into it to greater depth. The bottoms along the streams of the county vaty from a few rods to a mile or more in width. These lands occupy 71.09 square miles (45,498 acres), and constitute 9.86 percent of the entire area of the county. In topography they^are flat or have very slight undulations that represent old stream or overflow channels. Better drainage is needed in much of this area. The surface soil, o to 6^3 inches, is usually a brown silt loam contain- ing from 3.5 to' 5.3 percent of organic matter, the average being 4.4 percent, or 44 tons per acre. Tt is probably easier to maintain the fertility and the organic matter in this type than in the upland types, because of occasional overflow and the consequent deposition of material rich in humus and plant food. In physical composition this soil varies from a clay loam to a sandy loam, but the areas of these extreme types, especially of the sandy loam, are so small and so changeable that it is impracticable to try to show them on the map, as the next flood may change their boundaries. The subsurface is brown silt loam, becoming lighter in color and fre- quently in texture with depths It contains an average of 3.2 percent 6f or- ganic matter. The subsoil is a yellowish-drab silt loam varying in physical composition either to a clayey silt or to a sandy loam, or even to a sand in the lower sub- soil. Because of the way in which this type was formed, the different strata necessarily vary greatly. Where proper drainage is secured the type is quite productive. As a rule, where it is subject to frequent overflow nothing is needed except good farm- ing. Even the systematic rotation of crops is not so important where the land is subject to occasional overflows, but where it lies high or is protected from overflow a rotation including legume crops should be practiced, and ul- timately provision should be made for the enrichment of such protected land in both phosphorus and organic matter, and if necessary in limestone. Deep Peat (1301) A small area of deep peat, covering about 26 acres, is found in Section 1, Township 9 North, Range 3 East. This area needs drainage first of all. The surface soil, o to 6^3 inches, is a brown somewhat marly peat, varying in composition because of silts carried in and deposited by water. Both sub- surface and subsoil are brown peat mixed with shells. The samples collected and analyzed show great deficiency in potassium and only moderate amounts of phosphorus. The addition of 100 to 200 pounds per acre of potassium chlorid (often erroneously called “muriate” of potash) is almost certain to produce very marked benefit; and where this is done, phosphorus is likely to prove profitable in the future. When manure is applied, it will furnish potassium and produce increased crops, as a rule, but if the supply of manure is limited, it may be a better plan to use it on other Knox County 31 79/5] land, and improve this with commercial materials. (See also Bulletin 157, “Peaty Swamp Lands; Sand and ‘Alkali’ Soils.”) Shallozu Peat on Clay (1303) This type occupies an area of about 19 acres in the southwest quarter of Section 7, Township 9 North, Range 3 East, on the edge of the bottom land. It includes some medium peat, but shallow peat predominates. The surface soil, o to 6 ^ inches, is a brown peat containing some shells. The subsurface consists of a stratum of brown peat varying from 4 to 10 inches in thickness underlain by a drab clay that constitutes the subsoil. Aside from drainage, very deep plowing, which will mix some of the clay with the peaty stratum, is the only special treatment recommended. (See Bulletin 157 for results of such plowing on similar land.) 32 Soil Report No. 6 [August, APPENDIX A study of the soil map and the tabular statements concerning crop re- quirements, the plant-food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil improvement, and a careful study of the discussion of general prin- ciples and of the descriptions of individual soil types, will furnish the most necessary and useful information for the practical improvement and perma- nent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and impor- tant soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility in Illinois Soils,” which contains a colored gen- eral survey soil map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils” Bulletin No. 94; “Nitrogen Bacteria and Legumes” Bulletin No. 115, “Soil Improvement for the Worn Hill Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois” Circular No. no, “Ground Limestone for Acid Soils” Circular No. 127, “Shall we use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, “Some Results of Scientific Soil Treatment” and “Methods and Re- sults of Ten Years’ Soil Investigation in Illinois” Circular No. 165, “Shall we use ‘Complete’ Commercial Fertilizers in the Corn Belt?” NOTE. — Information as to where to obtain limestone, phosphate, bone meal, and po- tassium salts, methods of application, etc., will also be found in Circulars no and 165. Soil Survey Methods The detail soil survey of a county consists essentially of indicating on a map the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential : first, careful, well-trained men to do the work ; second, an ac- curate base map upon which to show the results of their work: and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal varia- tions and limits, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will survey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries will match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil map- ping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construction of these maps, while the most trustworthy county map avail- able is used in locating temporarily the streams, roads, and railroads, Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and cor- I9I3\ Knox County 33 rectecl if wrongly located. In order to make these verifications and correc- tions, each survey party is provided with an odometer for measuring dis- tances, and a plane table for determining directions of roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field; and the soil-type boundaries, additional streams, and necessary corrections are placed in their proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map, and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils for this purpose being car- ried in the field. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is taken by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while dis- tances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be located with as high a degree of accuracy as can be indicated by pencil on the scale of one inch to the mile. The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type grades into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, alluvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) the native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical, or mechanical, composition of the different strata composing the soil, as the percentages- of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. The common soil constituents are indicated in the following outline : Son, Characteristics Constituents of Soils Organic Matter J Comprising 1 1 vegetable undecomposed and partially decayed : material Soil Constituents .001 mm. 1 and less 001 mm. to .03 mm. . .03 mm. to 1. mm. , . .1. mm. to 32 mm. ...32. mm. and over Inorganic Matter 1 25 millimeters equal 1 inch. Further discussion of these constituents is given in Circular 82. Soil Report No. 6 [August, 34 Groups of Soil Typfs The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand and silt and a little clay. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and some silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams— Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 15 to 50 percent of gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no agricultural value. More or less organic matter is found in nearly all the above classes. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop ; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which this is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly im- portant, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but the rate of liberation is governed by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are lime- stone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may be supplied also by green-manure crops and crop residues, such as clover, cow- peas, straw, and cornstalks. The rate of decay of organic matter depends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which represents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly Knox County 35 20 tons of organic matter. But this organic matter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20tons of old, inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent additions of active organic matter, whether in applications of farm manure, in legume crops, or in grass- root sods of old pastures. Probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that with the normal rainfall of Illinois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such com- modity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts "of potassium, magnesium, calcium, etc., for the use of the growing crop. 'As already explained, fresh organic matter decomposes much more rap- idly than the old humus, which represents the organic residues most resistant to decay and which consequently has accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old, resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and thus furnish or liberate organic matter and inorganic food for bacteria, the bacteria, under such favorable conditions, appearing to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when incorporated with fresh farm manure; so that, when used together, two tons of the mixture may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bacterial action is also promoted by the presence of limestone. ' The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive Soil Report No. 6 [August, 36 condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil ; while in old, worn soils that are greatly in need of fresh, active, organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insuf- ficient; but even these plants (which include only the clovers, peas, beans, and vetches, among our common agricultural plants) secure from the soil alone six elements (phosphorus, potassium, magnesium, calcium, iron and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a building is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay; and, where the land is properly drained and properly tilled, such crops would frequently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the abso- lute needs of the crops. Crop Requirements The accompanying table shows the requirements of such crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are not known ever to limit the yield of general farm crops grown under normal conditions.) Table A. — Plant Food in Wheat, Corn, Oats, and Clover Produce Nitro- gen, pounds Phos- phorus, pounds Potas- sium, pounds Magne- sium, pounds Cal- cium, pounds Kind Amount Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw 2 l / z tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs K ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2 tons 31 5 52 7 15 Clover seed 4 bu. 7 2 3 1 1 Clover hay. . 4 tons 160 20 120 31 117 Total in grain and Seed 244 1 42 51 16 4 Total in four crops 510 1 77 322 68 168 l These amounts include the nitrogen contained in the clover seed or hay, which, however, may be secured from the air. 1913 ] Knox County 37 To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as possible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the ioo-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with limestone, phosphorus, and manure). ^ The importance of maintaining a rich surface soil cannot be too strongly emphasized. This is well illustrated by data from the Rothamsted Experi- ment Station, the oldest in the world. Thus on Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well fertilized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (o to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Rot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods of Liberating Plant Food Limestone and decaying organic matter are the principal materials the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria, which have power to transform the insoluble and unavail- able organic nitrogen into soluble and available nitrate nitrogen. At the same time, the products of this decomposition have power to dis- solve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing whatever to the soil, but always leaves the soil poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root devel- opment and also for the purpose of killing weeds* but more than this is unnecessary and unprofitable in seasons of normal rainfall; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows : 38 Soil Report No. 6 [ August , (i) If the soil is acid, apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC0 3 MgC0 3 ), which contains both calcium and magnesium and has slightly greater power to cor- rect soil acidity, ton for ton, than the ordinary calcium limestone (CaC0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years. On strongly acid soils, or in preparing the land for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks), or by using for feed and bedding practically all the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines : First year, corn. Second year, corn. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rota- tion. In grain farming, with small grain grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five-year rotation by cutting out either the second or the sixth year, and to a four-year system by omitting the fifth and sixth years. With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover; or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are : Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat, (4) clover, and (5) wheat (and clover) allows legumes to be seeded four times, and alfalfa may be grown on a sixth field for five or six years in the combination rotation, alternating between two fields every five years, or rotating over all the fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute sweet clover or alsike for red clover in about every third rotation, and at the same Knox County 39 1913] time to discontinue its use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover crop (seeded at the last cultivation) in the southern part of the state, and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named : 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires V/2 pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. I ton of timothy requires 24 pounds of nitrogen. I ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. I ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. For grain crops, such as wheat, corn, and oats, about two- thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. (See also discussion of “The Potassium Problem,” on pages below.) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in considerably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far se- cured shows positively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil improvement. The first application may well be one ton per acre, and subsequently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total ap- plication of from three to five or six tons per acre of raw phosphate con- taining \ 2]/ 2 percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in car- load lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phosphate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about i l / 2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rotation,, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. 40 Soil Report No. 6 [August, (4) Until the supply of decaying organic matter has been made ade- quate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid) . About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as to furnish available potas- sium and magnesium, and for a few years such use of kainit will no doubt be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for decaying organic matter, since this will necessitate returning to the soil either all produce except the grain (in grain farming) or the manure produced in live-stock farming. (Where hay or straw is sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent tne yeiiow- gray silt loam, and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tends to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently ; but where such lands are farmed under such a system, not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time ; and where the soil is acid a liberal use of limestone, as top-dressings if necessary, and occasional re- seeding with clovers will benefit both the pasture and indirectly the grain crops. Advantage oe Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years; but even a partial stand of clover the first time will probably provide a thousand times as many bac- teria for the next clover crop as one could afford to apply in artificial inocu- lation, for a single root-tubercle may contain a million bacteria developed from one during the season’s growth. This is only one of several advantages of the second course of the rota- tion over the first course. Thus the mere practice of crop rotation is an ad- vantage, especially in helping to rid the land of insects and foul grass and weeds. The deep-rooting clover crop is an advantage to subsequent crops because of that characteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage; and in systems of permanent soil improvement, such as are here advised and illustrated, more limestone and more phosphorus are provided than are needed for the meager or moderate crops produced during the first rotation, and conse- quently the crops in the second rotation have the advantage of such accumu- lated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. v This means that these systems tend positively toward the making of richer lands. The ultimate analyses recorded in the tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter: and 1913 1 Knox County 41 the accumulated information from careful and long-continued investigations in different parts of the United States clearly establishes the fact that in gen- eral farming these essentials can be supplied with greatest economy and profit by the use of ground natural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applications are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt, such as kainit, is used, it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 60 years (1852 to 1911), the yield of wheat has been 12.7 bushels on un- treated land, 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied; and, as further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of mag- nesium raised it to 29.2 bushels; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied, the average wheat crop re- moved 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained an abundance of limestone, but no organic matter was provided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 60 years (1852 to 1911) has been 14.2 bushels on untreated land, 38.1 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus have been applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.5 bushels, but, where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average has been 43.0 bushels. Thus, as an average of 60 years, the use of sodium pro- duced 1.8 bushels less wheat and 1.5 bushels more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop; but this must be expected to occur in time where no potassium is returned in straw or manure, and no provision made for liberating potassium from the supply still re- maining in the soil. If more than three-fourths of the potassium removed were returned in the straw (see Table A), and if the decomposition prod- ucts of the straw have power to liberate additional amounts of potassium from the soil, the necessity of purchasing potassium in a good system of farming on such land is very remote. While about half the potassium, nitrogen, and organic matter, and about one-fourth the phosphorus contained in manure will be lost by three or four months’ exposure in the ordinary pile in the barn yard, there 42 Soil Report No. 6 [August. is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while the animals destroy two-thirds of the organic matter and retain one-fourth of the nitrogen and phosphorus in average live-stock farming, they retain less than one-tenth of the potassium, from the food consumed ; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 67^ inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent cultivation) would permanently maintain the potassium in grain farming by renewal from the subsoil, provided one-third of the potassium is removed by cropping before the soil is carried away. From all of these facts it will be seen that the potassium problem is not one of addition but of liberation; and the Rothamsted records show that for many years other soluble salts have practically the same power as po- tassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other elements, is not known, but where much potassium is removed, as in the entire crops at Rothamsted, with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909, and 1910 on the Fairfield experiment field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium and costing $5.10, in- creased the yield of corn by 9.3 bushels per acre: while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4.00, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit has paid for itself; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield include an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure had been applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bush- els, while the 600 pounds of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was produced by the addition of either potassium sulfate or kainit; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for, and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant-food elements, es- pecially phosphorus . In laboratory experiments at the Illinois Experiment Station, it has been shown that potassium salts and most other soluble salts increase the solu- bility of the phosphorus in soil and in rock phosphate as determined by chem- ical analysis; also that the addition of glucose with rock phosphate in pot- culture experiments increases the availability of the phosphorus, as measured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the organic matter of the food consumed, it is easy to determine from Table A Knox County I9i3\ that more organic matter will be supplied in a proper grain system than in a strictly live-stock system; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious interference with the capillary movement of the soil moisture, a common danger from plowing' un- der too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming, or when both grain and straw are sold, of course the draft on potassium will then be so great that in time it must be renewed by some sort of application. As a rule, such farmers ought to secure manure from town, since they furnish the bulk of the material out of which manure is produced. Calcium and Magnesium When measured by the actual crop requirements for plant food, mag- nesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses 1 of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of calcium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of magnesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in T905'. And practically the same amount of calcium was found by analyzing the Rothamsted drainage waters. Common limestone, which is calcium carbonate (CaC 0 3 ), contains, when pure, 40 percent of calcium, so that 800 pounds of limestone are equivalent to 320 pounds of calcium. Where 10 tons per acre of ground limestone were applied at Edgewood, Illinois, the average annual loss during the next ten years amounted to 790 pounds per acre. The definite data from careful investigations seem to be ample to justify the conclusion that where lime- stone is needed at least 2 tons per acre should be applied every 4 or 5 years. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. ("See Soil Report No. 1.) Thus limestone has a positive value on some soils for the plant food which it supplies, in addition to its value in correcting soil acidity and in improving the physical condi- tion of the soil. Ordinary limestone (abundant in the southern and western parts of the state) contains nearly 800 pounds of calcium per ton; while a good grade of dolomitic limestone (the more common limestone of northern Illinois) contains about 400 pounds of calcium and 300 pounds of mag- nesium per ton. Both of these elements are furnished in readily available form in ground dolomitic limestone. 1 Reported by Doctor Bartow and associates, of the Illinois State Water Survey. UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 7 McDonough county soils By CYRIE G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and O. S. FISHER URBANA, ILLINOIS, SEPTEMBER, 1913 State Advisory Committee on - Soil Investigations Ralph Allen, Delavan A. N. Abbott, Morrison F. I. Mann, Gilman. J. P. Mason, Elgin C. V. Gregory, 538 S. Clark Street, Chicago Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief in Agronomy and Chemistry Soil Survey — J. G. Mosier, Chief A. F. Gustafson, Associate S. V. Holt, Associate H. W. Stewart, Associate H. C. Wheeler, Associate F. A. Fisher, Assistant F. M. W. Wascher, Assistant R. W. Dickenson, Assistant G. E. Gentle, Assistant O. I. Ellis, Assistant Soil Experiment Fields — O. S. Fisher, Assistant Chief J. E. Whitchurch, Associate E. E. Hoskins, Associate F. C. Bauer, Associate F. W. Garrett, Assistant H. C. Gilkerson, Assistant H. F. T. Fahrnkopf, Assistant A. F. Heck, Assistant H. J. Snider, Assistant Soil Analysis — J. H. Pettit, Chief Soil Biology — E. Van Alstine, Associate a. L. Whiting, Associate J P. Aumer, Associate W. R Schoonover, Assistant W. H. Sachs, Associate Gertrude Niederman, Assistant W. R. Leighty, Assistant L. R. Binding, Assistant Soils Extension — C. B. Clevenger, Assistant C. C. Logan, Associate introductory note About two-thirds of Illinois lies in the corn belt, where most of the prairie lands are black or dark brown in color. In the southern third of the state, the prairie soils are largely of a gray color. This region is better known as the wheat belt, altho wheat is often grown in the corn belt and corn is also a common crop in the wheat belt. Moultrie county, representing the corn belt ; Clay county, which is fairly repVesentative of the wheat belt ; and Hardin county, which is taken to rep- resent the unglaciated area of the extreme southern part of the state, were selected for the first Illinois Soil Reports by counties. While these three county soil reports were sent to the Station’s entire mailing list within the state, subsequent reports are sent only to the residents of the county con- cerned, and to any one else upon request. Each county report is intended to be as nearly complete in itself as it is practicable to make it, and, even at the expense of some repetition, each will contain a general discussion of important fundamental principles in order to help the farmer and landowner understand the meaning of the soil fer- tility invoice for the lands in which he is interested. In Soil Report No. 1, “Clay County Soils,” this discussion serves in part as an introduction, while in this and other reports, it will be found in the Appendix; but if necessary it should be read and studied in advance of the report proper. McDonough county soils By CYRIL G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and O. S. FISHER McDonough county is located in the upper Illinois glaciation about mid- way between the Illinois and Mississippi rivers. It is divided into two rather distinct topographic areas : the southwestern, consisting largely of rolling or broken land, with good drainage; and the northern and eastern, of gently undulating topography and containing several areas originally very poorly drained. The rolling or hilly land comprizes 25 percent of the entire area of the county. The difference in topography is due mainly to stream erosion, but it is very probable that an ice sheet which once covered the county did a great deal toward producing the present topography, especially in the region where erosion has played only a small part. The time when this county and much of the state was covered with this ice shqet is known as the Glacial period. During that period accumulations of snow and ice in parts of Canada became so great that they pushed southward until a point was reached where the ice melted as rapidly as it advanced. In moving across the country, the ice gathered up all sorts and sizes of stone and earth materials, including masses of rock, boulders, pebbles, and smaller particles. Some of these materials were carried for hundreds of miles and rubbed against the surface rocks or against each other until ground into powder. When the limit of advance was reached, where the ice largely melted, this material would accumulate in a broad undulating ridge or moraine. When the ice melted away more rap- idly than the glacier advanced, the terminus of the glacier would recede and leave the moraine of glacial drift to mark the outer limit of the ice sheet. The ice made many advances and with each advance and recession a terminal moraine was formed. These moraines are now seen as broad ridges that vary from one to ten miles in width. McDonough county possesses no distinct morainal ridge. Thruout the state, however, these advances and re- cessions of the ice sheet left a system of terminal moraines (irregularly con- centric with Lake Michigan) having generally a steep outer slope while the inner slope is longer and more gradual. (See state map in Bulletin 123.) The material transported by the glacier varied with the character of the rocks over which it passed. Granites, limestones, sandstones, shales, etc., were mixed and ground up together. This mixture of all kinds of boulders, gravel, sand, silt, and clay is called boulder clay, till, glacial drift, or simply drift. The grinding and denuding power of glaciers is enormous. A mass of ice 100 feet thick exerts a pressure of 40 pounds per square inch, and this ice sheet may have been thousands of feet in thickness. The materials car- ried and pushed along in this mass of ice, especially the boulders and pebbles, became powerful agents for grinding and wearing away the surface over which the ice passed. Ridges and hills were rubbed down, valleys filled, and surface features changed entirely. 2 Soil Repoet No. 7 [September, As the glacier melted in its final recession, the material carried in the great mass of ice was deposited somewhat uniformly, yet not entirely so, over the intermorainal tracts, leaving extensive areas of level, undulating, or rolling plains. Practically the whole of McDonough county is covered with a deposit of this glacial drift, or boulder clay, to a depth varying from io to 140 feet and averaging approximately 50 to 60 feet. An illustration of an old filled valley is found in Macomb. According to Leverett, a deep well in the city penetrates 145 feet of drift, while other wells in the vicinity, at the same altitude, show only 60 feet of drift. This indicates a buried valley that was at least 85 feet deep. The surface left by the glacier in this county was slightly rolling, but not sufficiently so for complete drainage. Physiography McDonough county lies entirely in the drainage basin of the Illinois river. The highest part of the county is the northwest, where an altitude of 775 feet above sea level is reached. The lowest part is in the bottom land of Crooked creek at the south side of the county, which lies at an altitude of 500 feet. The average altitude is approximately 690 feet. Following are the altitudes of some of the railroad stations: Adair, 645; Bardolph, 671; Blandinsville, 730; Bushnell, 658; Colchester, 694; Good Hope, 714; Ma- comb, 700; New Philadelphia, 673; Prairie City, 659; Sciota, 754; Ten- nessee, 686. At least 90 percent of McDonough county is drained thru Crooked creek ; the other 10 percent is drained eastward into Spoon river. The larger streams of the county have cut valleys from 50 to 200 feet below the general upland. This has permitted the small tributaries to do considerable erosion, and as a result the upland adjacent to these larger streams is largely cut up into hills and valleys unsuited for ordinary agriculture. Soil Material and Soil Types The Illinois glacier covered McDonough county and left a thick mantle of drift, completely burying the old soil that preceded it. Then a long period elapsed during which a deep soil, known as the old Sangamon soil, was formed on the Illinois drift. Later, other ice invasions of Illinois oc- curred, but they covered only the northern part of the state. (See state map in Bulletin 123, Iowan and Wisconsin glaciations.) These later ice sheets did not reach McDonough county, but finely ground rock (rock flour) in immense quantities was carried south by the waters from the melting ice and deposited on the flooded plains of streams where it was picked up by the wind, carried out of these bottom lands and finally deposited on the upland, burying the drift material deposited by the Illinois glacier and the old Sangamon soil 1 to a depth of 5 to 20 feet or more. This wind-blown material, called loess, represents a mixture of all kinds of material over which the glacier passed. After the loessal material was deposited over the country, the surface stratum became mixed with more or less organic matter and thus was gradu- ally changed into soil. Surface washing has produced other changes. J The Sangamon soil may sometimes be seen in cuts as a somewhat dark or bluish sticky clay or a weathered zone of yellowish or brownish clay. 191S ) McDonough County 3 The soils of McDonough county are divided into the three following classes : (1) Upland prairie soils, rich in organic matter. These were originally covered with wild prairie grasses, the partially decayed roots of which have been the source of the organic matter. The flat, naturally poorly drained prairie land contains the higher amount of organic matter because the grasses and roots grew more luxuriantly there and were largely preserved from de- cay by the higher moisture content of the soil. (2) Upland timber soils, including those zones along stream courses over which the forests once extended. These soils contain much less organic mat- ter than the upland prairie soils because the large roots of dead trees and the surface accumulations of leaves, twigs, and fallen trees were burned by for- est fires or suffered almost complete decay. The timber lands are divided chiefly into two classes — the undulating and the hilly areas. (3) Swamp and bottom-land soils, which include the flood plains along streams. Table 1 shows the area of each type of soil in McDonough county and its percentage of the total area. It will be noted that the common prairie soil (the brown silt loam) occupies 55 percent of the area of the county, while the yellow silt loam of the hilly land is the next most extensive type, covering 25 percent of the county. Table 1.— Soil Types of McDonough County Soil type No. Name of type Area in square miles Area in acres Percent of total area 526 (a) Upland Prairie Soils (page 22) Brown silt loam. 318.18 203 637 55.44 520 Black clay loam 19.22 12 301 3.35 528 Brown-gray silt loam on tight clay 29.25 18 720 5.10 525.1 Black silt loam on clay 7.24 4 634 1.26 535 (b) Upland Timber Soils (page 27) Yellow silt loam 144.41 92 422 25.16 534 Y ellow-gray silt loam 39.00 24 960 6.79 532 Light gray silt loam on tight clay 2.53 1 619 .44 1326 (c) Swamp and Bottom-Land Soils (page 34) Deep brown silt loam 14.02 8 973 2.44 (d) Miscellaneous Lake .10 64 .02 Total 573.95 367 330 100.00 The accompanying maps show the location and boundary lines of every type of soil in the county, even down to areas of a few acres; and in Table 2 are reported the amounts of organic carbon (the best measure of the organic matter) and the total amounts of the five important elements of plant food contained in 2 million pounds of the surface soil of each type (the plowed soil of an acre about 6% inches deep). In addition, the table shows the amount of limestone present, if any, or the amount of limestone required to neutralize the acidity existing in the soil. 1 ‘The figures given in Table 2 (and in the corresponding tables for subsurface and sub- soil) are the averages for all determinations, with some exceptions of limestone present or required. Some soil types, particularly those which are subject to erosion, may vary from acid to alkaline, especially in the subsurface or subsoil ; and in such cases abnormal results are discarded, a report of the normal conditions being more useful than any average of figures involving both plus and minus quantities. 4 Soil Report No. 7 [September, THE INVOICE AND INCREASE OF FERTILITY IN McDONOUGH COUNTY SOILS Soil Analysis In order to avoid confusion in applying in a practical way the technical information contained in this report, the results are given in the most simpli- fied form. The composition reported for a given soil type is, as a rule, the average of many analyses, which, like most things in nature, show more or less variation ; but for all practical purposes the average is most trustworthy and sufficient. (See Bulletin 123, which reports the general soil survey of the state, together with many hundreds individual analyses of soil samples representing twenty-five of the most important and most extensive soil types in the state.) The chemical analysis of the soil gives the invoice of fertility actually present in the soil strata sampled and analyzed, but, as explained in the Ap- pendix, the rate of liberation is governed by many factors. Also, as there stated, probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that the productive power of normal soil in humid sections depends upon the stock of plant food contained in the soil and upon the rate at which it is liberated. The fact may be repeated, too, that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agri- cultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, while seven are secured from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes) in case the amount liberated from the soil is insufficient. But even the leguminous plants (which include the clovers, peas, beans, alfalfa, and vetches) , in common with other agricultural plants, secure from the soil alone six elements (phosphorus, potassium, mag- nesium, calcium, iron, and sulfur) and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Table A in the Appendix shows the requirements of large crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally from natural sources in sufficient abundance, compared with the amounts needed by plants, so that they are never known to limit the yield of common farm crops.) As already stated, the data in Table 2 represent the total amounts of plant-food elements found in 2 million pounds of surface soil, which cor- responds to an acre about 6% inches deep. This includes at least as much soil as is ordinarily turned with the plow, and represents that part with which the farm manure, limestone, phosphate, or other fertilizer applied in soil im- provement is incorporated. It is the soil stratum that must be depended upon HANCOCK COUNT 1 ! Legend UPLAND PRAIRIE SOILS 26 Brown silt loan UPLAND TIMBER SOILS [jkl Yellow-gray < 532 L ' eht gfl SOIL SURVEY MAP OF l( UNIVERSITY OF ILLINOIS AGRK ; 1 9 i ■ ^ \ t f>7 AMP AND BOTTOM LAND SOILS ■ Deep brown silt loam Scale : Miles ICDONOTIGH COUNTY 1/rURAL EXPERIMENT STATION F IT LT ON COUNTY 3 1H18 J McDonough County 5 Tabue 2.- Fertility in the Soius of McDonough County Average pounds per acre in 2 million pounds of surface soil (about 0 to 6% inches) Soil type No. Soil type Total organic carbon Total nitro- gen Total phos- phorus Total potas- sium Total magne- sium Total calcium Lime- stone present Lime- stone requir’d Upland Prairie Soils 526 Brown silt loam 49 810 4 260 1 098 33 090 9 794 11 460 70 520 Black clay loam 78 470 6 167 1 587 29 640 13 667 19 673 30 528 Brown-gray silt loam on tight clay 39 800 3 400 900 31 740 6 400 8 200 100 525.1 Black silt loam on clay 64 180 5 420 940 30 960 10 440 15 460 60 Upland Timber Soils 534 Yellow-gray silt 27 070 2 620 880 36 870 6 270 8 105 70 535 Y ellow silt loam 21 460 2 140 830 37 530 6 490 7 060 60 532 Light gray silt loam on tight clay 16 080 1 460 920 35 140 6 420 6 680 140 Swamp and Bottom-Land Soils Deep brown silt 1 1 i loam 47 140 4 580 1 740 37 360 1 9 140 10 960 | in large part to furnish the necessary plant food for the production of crops, as will be seen from the information given in the Appendix. Even a rich subsoil has little or no value if it lies beneath a worn-out surface, for the weak, shallow-rooted plants will be unable to reach the supply of plant food in the subsoil. If, however, the fertility of the surface soil is maintained at a high point, then the plants, with a vigorous start from the rich surface soil, can draw upon the subsurface and subsoil for a greater supply of plant food. By easy computation it will be found that the most common prairie soil of McDonough county does not contain more than enough total nitrogen in the plowed soil for the production of maximum crops for nine rotations (36 years) ; while the upland timber soils contain, as an average, only one-half as much nitrogen as the prairie land. With respect to phosphorus, the condition differs only in degree, nine- tenths of the soil area of the county containing no more of that element than would be required for fifteen crop rotations if such yields were secured as are suggested in Table A of the Appendix. It will be seen from the same table that in the case of the cereals about three-fourths of the phosphorus taken from the soil is deposited in the grain, while only one-fourth remains in the straw or stalks. On the other hand, the potassium is sufficient for 25 centuries if only the grain is sold, or for 400 years even if the total crops should be removed and nothing returned. The corresponding figures are about 2500 and 600 years for magnesium, and about 15,000 and 300 years for calcium. Thus, when measured by the actual crop requirements for plant food, potassium is no more limited than magnesium and calcium, and, as explained in the Appen- Soil Report No. 7 [September, Plate 1. — Wheat in 1911 on Urbana Field Cover Crops and Crop Residues Plowed Under Average Yield, 3S.2 Bushels Per Acre dix, with these elements we must also consider the fact that loss by leaching is far greater than by cropping. These general statements relating to the total quantities of plant food in the plowed soil certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the needs of large crop yields for even one or two generations of people. The variation among the different types of soil in McDonough county with respect to their content of important plant-food elements is also very marked. Thus, the richest prairie land, the black clay loam, contains about twice as much phosphorus and two to three times as much nitrogen as the common upland timber soils.. On the other hand, the most significant fact revealed by the investigation of the soils of this county is the low phosphorus content of the common brown silt loam prairie, a type of soil that covers more than half the entire county. The market value of this land is about $200 an acre, and yet an application of forty dollars’ worth of fine-ground z f H HANCOCK COUNTS LEGEND UPLAND PRAIRIE SOILS g 26 I Brown silt loam’ H Buck ='*>' |oam 1^1 Brown -gray silt loam on tight clay . Black silt loam on clay. UPLAND TIMBER SOILS 3^1 Yellow-gray silt loam I ^2 Light gray silt loam on tight < SOIL SURVEY MAP OF UNIVERSITY OF ILLINOIS AGRIC 1 I i 326 i Deep brown silt loam l- CDONOUGH COUNTY TURAL EXPERIMENT STATION i FULTON COUNTY McDonough County 7 1913 ] Plate 2. — Wheat in 1911 on Urbana Field Cover Crops and Crop Residues Plowed Under Fine-Ground Rock Phosphate Applied Average Yield, 50.1 Bushels Per Acre raw rock phosphate would double the phosphorus content of the plowed soil, and, if properly made, would in the near future double the yield of clover. If the clover were then returned to the soil, either directly or in farm manure, the combined effect of phosphorus and increased nitrogenous organic matter, with a good rotation of crops, would in time double the yield of corn on most farms. The same treatment would produce equally good results on the un- dulating upland timber soils. With more than 4000 pounds of nitrogen in the prairie soil and an in- exhaustible supply in the air, with 33,000 pounds of potassium in the same soil, and with practically no acidity, the economic loss in farming such land with only 1100 pounds of total phosphorus in the plowed soil can be ap- preciated only by the man who fully realizes that in less than one generation the crop yields could be doubled by adding phosphorus, — without change of seed or season and with very little more work than is now devoted to the 8 Soil Report No. 7 [September, Plate 3.— Wheat in 1911 on Urbana Field Cover Crops and Farm Manure Plowed Under Average Yield, 34.2 Bushels Per Acre fields. Fortunately, some definite field experiments have already been con- ducted on this most extensive type of soil, both in the upper Illinois glacia- tion in Knox county and on similar soil in the early Wisconsin glaciation, as at Urbana in Champaign county, at Sibley in Ford county, and at Blooming- ton in McLean county. Results of Field Experiments at Urbana A three-year rotation of corn, oats, and clover was begun on the North Farm at the University of Illinois in 1902, on three fields of typical brown silt loam prairie land which, after twenty years or more of pasturing, had grown corn in 1895, 1896, and 1897 (when careful records were kept of the yields produced) and had then been cropped with clover and grass on one field, oats on another, and oats, cowpeas, and corn on the third field, until 1901. As an average of the first three years (1902-1904) phosphorus 191S ] McDonough County 9 Peate 4. — Wheat in 1911 on Urbana Fieed Cover Crops and Farm Manure Peowed Under Fine-Ground Rock Phosphate Appeied Average Yieed, 51.8 Bushees Per Acre increased the crop yields per acre by .68 ton of clover, 8.8 bushels of corn, and 1.9 bushels of oats. During the second three years (1905-1907) it pro- duced average increases of .79 ton of clover, 13.2 bushels of corn, and 11.9 bushels of oats. During the third course of the rotation (1908-1910) it pro- duced average increases of 1.05 tons of clover, 18.7 bushels of corn, and 8.4 bushels of oats. For convenient reference the results are summarized in Table 3. Wheat is grown on the University South Farm in a rotation experiment started more recently. As an average of the four years 1908 to 1911, raw rock phosphate (with no previous application of bone meal) increased the yield of wheat by 10.3 bushels per acre. Here, too, as an average of the four years, the phosphorus applied paid back about twice its cost. In the grain system of farming, the yield of wheat in 1911 was 35.2 bushels per 10 Soil Report No. 7 [ September , acre where cover crops and crop residues are plowed under without the use of phosphorus; but where rock phosphate is used the average yield was 50.1 bushels (see Plates 1 and 2). In the live-stock system, the yield of wheat in 19 1 1 was 34.2 bushels where manure and cover crops are used without phosphate; and 51.8 bushels, as an average, where rock phosphate is used in addition (see Plates 3 and 4). These results emphasize the cumulative effect of permanent systems of soil improvement. Table 3. — Effect of Phosphorus on Brown Silt Loam at Urbana (Average increase per acre) Rotation Years Corn, bu. Oats, bu. Clover, tons Value of increase 1 Cost of treatment 1 First 1902,-3,-4 8.8 1.9 .68 $ 7.73 $7.50 Second 1905,-6,-7 13.2 11.9 .79 12.93 7.50 Third 1908,-9,-10 18.7 8.4 1.05 15.37 7.17 ‘Prices used are 35 cents a bushel for corn, 30 cents for oats, $6 a ton for clover hay, 10 and 3 cents a pound, respectively, for phosphorus in bone meal and in rock phosphate. (Only steamed bone meal was used from 1902 to 19J7, but subsequently three times as much rock phosphate has been used, at less cost, on one half of each phosphor- us plot.) Wheat has also been grown on the North Farm during the last three years ( 191 1, ’12, ’13), and the average increase produced by phosphorus (part in bone meal and part in raw phosphate) has been 12.4 bushels per acre per year. Results of Experiments on Sibley Field Table 4 gives the results obtained during the past eleven years from the Sibley soil experiment field located in Ford county on the typical brown silt loam prairie of the Illinois corn belt. Previous to 1902 this land had been cropped with corn and oats for man) years under a system of tenant farming, and the soil had become somewhat deficient in active organic matter. While phosphorus was the limiting ele- ment of plant food, the supply of nitrogen becoming available annually was but little in excess of the phosphorus, as is well shown by the corn yields for 1903, when the addition of phosphorus produced an increase of 8 bushels, nitrogen produced no increase, but nitrogen and phosphorus together in- creased the yield by 15 bushels. After six years of additional cropping, however, nitrogen appeared to become the most limiting element, the increase in the corn in 1907 being 9 bushels from nitrogen and only 5 bushels from phosphorus, while both together produced an increase of 33 bushels. By comparing the corn yields for the four years 1902, 1903, 1906, and 1907, it will be seen that the untreated land has apparently grown less productive, whereas, on land re- ceiving both phosphorus and nitrogen the yield has appreciably increased, so that in 1907, when the untreated rotated land produced only 34 bushels of corn per acre, a yield of 72 bushels (more than twice as much) was pro- duced where lime, nitrogen, and phosphorus had been applied, altho the two plots produced exactly the same yield (57.3 bushels) in 1902. Even in the unfavorable season of 1910, the yield of the highest produc- ing plot exceeded the yield of the same plot in 1902, while the untreated land produced less than half as much as it produced in 1902. The prolonged drouth of 1911 resulted in almost a failure of the corn crop, but nevertheless McDonough County 11 101S ] Tabus 4. — Crop Yieuds in Soiu Experiments, Sibuey Fieud Brown silt loam prairie; early Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Corn 1906 Icorn 1907 Oats 1908 Wheat 1909 Corn 1910 Corn 1911 Oats 1912 Plot Soil treatment * applied Bushels per acre 101 None 57.3 50.4 74.1 29.5 36.7 33.9 25.9 25.3 26.6 20.7 84.4 102 Eime 60.0 54.0 74.7 31.7 39.2 38.9 24.7 28.8 34.0 22.2 85.6 103 Lime, nitrogen . . 60.0 54.3 77.5 32.8 41.7 48.1 36.3 19.0 29.0 22.4 25.3 104 Lime, phosphorus Lime, potassium. 61.3 62.3 92.5 36.3 44.8 43.5 25.6 32.2 52.0 31.6 92.3 105 56.0 49.9 74.4 30.2 37.5 34.9 22.2 23.2 34.2 21.6 83.1 106 Lime, nitrogen, phosphorus . . . 57.3 69.1 88.4 45.2 68.5 72.3 45.6 33.3 55.6 35.3 42.2 107 Lime, nitrogen, potassium. . . . 53.3 51.4 75.9 37.7 39.7 51.1 42.2 25.8 46.2 20.1 55.6 108 Lime, phosphorus, potassium. 58.7 60.9 80.0 39.8 41.5 39.8 27.2 28.5 43.0 31.8 79.7 109 Lime, nitrogen, phos., potas. . . 58.7 65.9 82. 5 I 48.0 69.5 80.1 52.8 35.0 58.0 35.7 57.2 110 Nitro., phos., potassium . . - 60.0 60.1 85. o| 48.5 63.3 72.3 44.1 30.8 64.4 31.5 54.1 Average Increase: Bushels per Acre For nitrogen -1.7 3.4 .7 6.4 14.1 23.6 19.3 .1 6.4 1.6 -40.1 For phosphorus 1.7 12.1 10.7 9.2 16.5 15.7 6.4 8.1 16.3 12.0 5.4 For potassium For nitro., phos., over -3.0 -2.9 —5.1 2.4 —1.5 1.0 3.0 - .2 2.7 — .6 7.5 phos For phos., nitro. over -4.0 6.8 —4.1 8.9 23.7 28.8 20.0 1.1 3.6 3.7 -50.1 nitro —2.7 14.8 10.9 12.4 26.8 24.2 9.3 14.3 26.6 12.9 16.9 For potas., nitro., phos. over nitro., phos. . . . 1.4 -3.2 —5.9 2.8 1.0 7.8 7.2 1.7 2.4 .4 15.0 Value of Crops per Acre in Eleven Years Plot Soil treatment applied Total value of eleven crops Value of increase 101 102 None. $ 172.73 184.75 $ 12.03 103 104 105 L/ime, nitrogen 167.42 214.50 173.22 — 5.31 41.77 .49 Lime, phosphorus Lime, potassium. 106 107 108 Lime, nitrogen, phosphorus 233.15 188.19 200.37 60.42 15.46 27.64 Lime, nitrogen, potassium Lime, phosphorus, potassium 109 110 Lime, nitrogen, phosphorus, potassium 244.62 233.54 71.89 60.81 Nitrogen, phosphorus, potassium Value of Increase per Acre in Eleven Years Cost of increase For n For p For n For p For / a itrogen hosphorus itrogen and phosphorus over phosphorus hosphorus and nitrogen over nitrogen wtassium, nitrogen, and phosphorus over nitrogen md phosphorus t $-17.33 29.75 18.65 65.73 11.47 $ 165.00 27.50 165.00 27.50 27.50 12 Soil Eepoet No. 7 [September, the effect of soil treatment was seen. Phosphorus appeared to be the first limiting element again in 1909, 1910, and 1911; while the lodging of oats, especially on the nitrogen plots, in the exceptionally favorable season of 1912, produced very irregular results. In the lower part of Table 4 are shown the total values per acre of the eleven crops from each of the ten different plots, the amounts varying from $167.42 to $244.62; also the value of the increase produced in crop yields above the value of the yields from the untreated land, corn being val- ued at 35 cents a bushel, oats at 30 cents, and wheat at 70 cents. Phos- phorus without nitrogen has produced $29.75 i n addition to the increase by lime; but with nitrogen it has produced $65.73 above the crop values where only lime and nitrogen have been used. The results show that in 25 cases out of 44 the addition of potassium has decreased the crop yields. Even under the most favorable conditions, and with no effort to liberate potassium from the soil by adding organic matter, potassium has paid back less than half its cost. By comparing Plots 101 and 102, and also 109 and no, it will be seen that lime has produced an average increase of $11.55, or more than $1 an acre a year. Altho this increase may have been above normal on these plots because of the condition of the soil at the beginning of the experiment, it suggests that the time is here when limestone must be applied to some of these brown silt loam soils. While nitrogen, on the whole, has produced an appreciable increase, es- pecially on those plots to which phosphorus has also been added, it has. cost, in commercial form, so much above the value of the increase produced that the only conclusion to be drawn, if we are to utilize this fact to advantage, is that the nitrogen must be secured from the air. Results op Experiments on Bloomington Field Space is taken to insert Table 5, giving all the results thus far obtained from the Bloomington soil experiment field, which is also located on the brown silt loam prairie soil of the Illinois corn belt. The general results of the eleven years’ work on the Bloomington field tell much the same story as those from the Sibley field. The rotations have differed since 1905 by the use of clover and the discontinuing of the use of commercial nitrogen on the Bloomington field ; in consequence of which phos- phorus without commercial nitrogen, on the Bloomington field, has produced an even larger increase ($89.92) than has been produced by phosphorus and nitrogen over nitrogen on the Sibley field ($65.73). It should be stated that a draw runs near Plot no on the Bloomington field, that the crops on that plot are sometimes damaged by overflow or im- perfect drainage, and that Plot 101 occupies the lowest ground on the oppo- site side of the field. In part because of these irregularities and in part be- cause only one small application has been made, no conclusions can be drawn in regard to lime. Otherwise all results reported in Table 5 are considered reliable. They not only furnish much information in themselves, but they also offer instructive comparison with the Sibley field. Wherever nitrogen has been provided, either by direct application or by the use of legume crops, the addition of the element phosphorus has produced very marked increases, the average yearly increase for the Bloomington field being worth $7.11 an acre. This is $4.61 above the cost of the phosphorus 1913 ] McDonough County 13 Tabus S Crop Yields in Soil Experiments, Bloomington Field Brown silt loam prairie; early Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 Wheat Clover 1905 | 1906 Corn 1907 Corn 19v.8 Oats 1909 Clover 2 1910 Wheat Com 1911 | 1912 o s Soil treatment applied Bushels or tons per acre 101 None 30.8 63.9 54.8 30.8 .39 60.8 40.3 46.4 1.56 22.5 55.2 102 Lime 37.0 60.3 60.8 28.8 .58- 63.1 35.3 53.6 1.09 22.5 47.9 103 Lime, crop res. 1 .... 35.1 59.5 69.8 30.5 1 .46 64.3 36.9 49.4 (.83) 25.6 62.5 104 Lime, phosphorus. . 41.7 73.0 72.7 39.2 1.65 82.1 47.5 63.8 4.21 57.6 74.5 105 Lime, potassium . . . 37.7 56.4 62.5 1 33 ' 2 .51 64.1 36.2 45.3 1.26 21.7 £7.8 106 Lime, residues, 1 phosphorus 43.9 77.6 85.3 50.9 3 78.9 45.8 72.5 (1.67) 60.2 86.1 107 Lime, residues, 1 potassium 40.4 58.9 66.4 29.5 .81 64.3 31.0 51.1 (.33) 27.3 58.9 108 Lime, phosphorus, potassium 50.1 74.8 70.3 37.8 2.36 81.4 57.2 59.5 3.27 54.0 73.2 109 Lime, res., 1 phos., 52.7 80.9 90.5 51.9 8 88.4 58.1 64.2 (.42) 60.4 83,4 110 potassium Res., phosphorus, 52.3 73.1 71.4 51.1 3 78. OJ 51.4 55.3 (.60) 61.0 78.3 potassium Average Increase: Bushels or Tons per Acre For residues 1.4 3.1 11.4 5.9 -.96 1.3 -l.i 3.7 -1.64 4.4 7.9 For phosphorus 9.5 17.8 14.8 14.4 .41 18.8 18.0 15.1 1.51 33.9 24.0 For potassium 5.8 .2 .3 .7 .25 2.4 4.2 -4.8 -.63 — .6 2.1 For res., phos. overphos. 2.2 4.6 12.6 11.7 -1.65 -3.2 -1.7 8.7 -2.25 2.6 11.6 For phos., res. over res. For potas., res., phos. 8.8 18.1 15.5 20.4 - .46 14.6 8.9 23.1 .84 34.6 23.6 over res., phos 8.8 3.3 5.2 1.0 .00 9.5 12.3 -8.3 -1.25 .2 -2.7 Value of Crops per Acre in Eleven Years o Soil treatment applied Total valued Value of s eleven crops increase io: None 8167.22 102 Lime 165.52 —$1.70 :t03 Lime, residues 173.17 5.95 104 Lime, phosphorus 255.44 88.22 105 Lime, potassi :m 169.66 2.44 106 Lime, residues, phosphorus Lime, residues, potassium 251.43 84.21 107 170.57 3.36 108 Lime, phosphorus, potassium 256.92 [ 89.70 109| Lime, residues, phosphorus, potassium 254.76 87.54 r.j 1 Residues, phosphorus, potassium 236.66 69.44 ■ Value of Increase per Acre in Eleven Years | Cost of increase For residues $ 7.65 ? For phosphorus 89.92 $27.50 For residues and phosphorus over phosphorus —4.01 ? F or phosphorus and residues over residues For potassium, residues, and phosphorus over residues 78.26 27.50 and phosphorus 3.33 27.50 ‘Commercial nitrogen was used 1902-1905. 9 The figures in parentheses mean bushels of seed; the others, tons of hay. •Clover smothered by previous wheat crop. 14 Soil Beport No. 7 [September, in 200 pounds of steamed bone meal, the form in which it is applied to the Sibley and the Bloomington fields. On the other hand, the use of phosphorus without nitrogen will not maintain the fertility of the soil (see Plots 104 and 106, Sibley field). As the only practical and profitable method of supplying nitrogen, a liberal use of clover or other legumes is suggested, the legume to be plowed under either directly or as manure, preferably in connection with the phosphorus applied, especially if raw rock phosphate is used. From the soil of the best treated plots on the Bloomington field, 160 pounds per acre of phosphorus, as an average, have been removed in the eleven crops. This is equal to more than 13 percent of the total phosphorus con- tained in the surface soil of an acre of the untreated land. In other words, if such crops could be grown for eighty years, they would require as much phosphorus as the total supply in the ordinary plowed soil. The results plainly show, however, that without the addition of phosphorus such crops cannot be grown year after year. Where no phosphorus has been applied, the crops have removed only 107 pounds of phosphorus in the eleven years, which is equivalent to only 9 percent of the total amount (1,200 pounds) that was present in the surface soil at the beginning of the experiment in 1902. The total phosphorus applied from 1902 to 1912, as an average of all plots where it has been used, has amounted to 275 pounds per acre and has cost $27.50. This has paid back $84.91, or 300 percent on the investment; whereas potassium, used in the same number of tests and at the same cost, has paid back only $1.59 per acre in the eleven years, or less than 6 percent of its cost. Are not these results to be expected from the composition of the soil and the requirements of crops? (See Table 2, page 5, and also Table A in the Appendix. ) Nitrogen was applied to this field, in commercial form only, from 1902 to 1905 ; but clover was grown in 1906 and 1910, and a catch crop of cow- peas after the clover in 1906. The cowpeas were plowed under on all plots, and the 1910 clover (except the seed) was plowed under on five plots ^103, 106, 107, 109, and no). Straw and corn stalks have also been returned to these plots in recent years. The effect of returning these residues to the soil is already appreciable (an average increase of 4.4 bushels of wheat in 1911 and 7.9 bushels of corn in 1912) and probably will be more marked on subsequent crops. Indeed, the large crops of corn, oats, and wheat grown on Plots 104 and 108 during the eleven years have drawn their nitrogen very largely from the natural supply in the organic matter of the soil. The roots and stubble of clover contain no more nitrogen than the entire plant takes from the soil alone, but they decay rapidly in contact with the soil and prob- ably hasten the decomposition of the soil humus and the consequent libera- tion of the soil nitrogen. But of course there is a limit to the reserve stock of humus and nitrogen remaining in the soil, and the future years will un- doubtedly witness a gradually increasing difference between Plots 104 and 106, and between Plots 108 and 109, in the yields of grain crops. Plate 5 shows graphically the relative values of the eleven crops for the eight comparable plots, Nos. 102 to 109. The cost of the phosphorus is in- dicated by that part of the diagram above the short crossbars. It should be kept in mind that no value is assigned to clover plowed under except as it reappears in the increase of subsequent crops. Plots 106 and 109 are heavily handicapped because of the clover failure on those plots in 1906 and the poor yield of clover seed in 1910, whereas Plots 104 and 108 produced a fair crop in 1906 and a very large crop in 1910. As an average, Plots 106 and 109 are only $3.09 behind Plots 104 and 108 in the value of the eleven crops 191S] McDonough County 15 102 103 104 105 106 107 108 109 OR P K RP RK PK RPK $165.52 $173.17 $255.44 $169.66 $251.43 $170.57 $256.92 $254.76 Pi, ate 5 Crop Values for Eleven Years Bloomington Experiment Field (R=residues; P = phosphorus; K=potassium, or kalium) harvested, and this would have been covered by about Yi bushel more clover seed in 1906 or 1910, or it may be covered by 10 bushels more corn in 1913. The values from Plots 103 and 107 average $4.28 more than the values from Plots 102 and 105. (See also table on last page of cover.) Results of Field Experiments at Galesburg In Tables 6, 7, and 8 are reported in detail the results obtained from the University of Illinois soil experiment field near Galesburg, on the line be- tween Knox and Warren counties, on the brown silt loam prairie soil of the upper Illinois glaciation. A six-year rotation has been practiced on this field since 1904. During the first six years the order of cropping was corn, corn, oats, wheat, followed by two years of clover and timothy. Since then the rotation has been corn, corn, oats, clover, wheat, clover. There are only three independent series of plots, so that while corn is grown every year the other crops are harvested only in alternate years, altho clover should be on the field every year, either in the stubble of the oats and wheat or as a regular crop. Each series contains twenty individual fifth-acre plots, 2 rods wide and 16 rods long, with half-rod division strips cultivated and cropped between the plots, a quarter-rod border cultivated and cropped surrounding each 16 Soil Repoet No. 7 [September, Table 6.— Crop Yields in Soil Experiments, Galesburg Field: Series 100 Brown silt loam prairie; upper Illinois glaciation Corn 1904 Corn 1905 Oats 1906 [wheat 1907 Clo- ver 1 1908 Timo- thy 1 1909 Corn 1910 Corn 1911 Oats 1912 Plot Soil treatment applied Bushels or tons per acre 101 Lime 63.8 52.5 53.8 34.0 2.71 2.04 59.8 66.5 53.3 102 Residues, lime 67.3 49.8 53.6 41.4 (.96) (3.83) 72.6 75.1 56.9 103 Manure, lime 64.7 48.1 50.3 31.6 2.59 1.83 77.6 81.0 60.0 104 Cover crop, manure, lime . . . 65.3 46.5 46.7 32.8 2.61 1.70 77.9 78.9 70.2 105 Lime 74.7 54.9 52.3 35.1 2.80 2.05 66.2 67.4 60.8 106 Lime, phosphorus 78.2 66.1 53.9 41.9 3.18 2.58 72.4 79.4 68.6 107 Residues, lime, phosphorus 75.9 63.1 55.0 41.3 (.67) (4.92) 78.0 83.8 65.2 108 Manure, lime, phosphorus.. 72.6 61.1 54.2 37.9 3.18 2.36 74.6 79.8 77.3 109 Cover crop, manure, lime, phosphorus 74.1 60.0 54.2 40.0 3.15 2.33 74.0 79.1 74.4 110 Lime 72.4 58.8 50.5 32.7 2.65 1.74 61.5 59.2 54.5 111 Lime, phosphorus, po- tassium 81.2 72.3 53.9 36.6 3.21 2.42 74.5 81.1 70.9 112 Residues, lime, phosphorus, potassium 82.3 71.0 59.4 41.1 (.58) (5.00) 81.9 83.7 59.5 113 Manure, lime, phosphor- us, potassium 77.1 72.2 52.8 36.1 3.45 2.49 77.6 82.4 74.4 114 Cover crop, manure, lime, phos., potassium 89.4 69.9 54.5 38.7 3.36 2.55 75.9 85.0 70.0 115 Lime 81.2 68.1 62.8 36.8 2.99 2.19 59.4 67.3 53.0 116 Residues ... 77.1 61.8 57.3 38.2 (1.17) (5.33) 70.6 68.9 52.0 117 Residues, phosphorus 79.4 64.2 60.0 36.2 (1.25) (5.50) 75.0 77.5 66.1 118 Residues, phosphorus, potassium 82.3 70.8 52.0 40.9 (1.38) (4.75) 78.3 78.4 68.1 119 Residues, lime, nitrogen, phos., potassium 87.1 76.3 66.2 46.0 (1.08) (5.00) 74.8 79.3 67.3 120 None 82.9 65.1 65.3 45.8 3.04 2.82 72.7 67.4 70.2 Increase for residues —2.19 — .89 5.9 4.3 —7.3 Increase for manure 7.7 5.4 6.3 Increase for phosphorus 6.2 10.7 3.4 3.6 .26 .42 1.8 5.7 10.3 Increase for potassium 6.4 8.3 —.9 — 8 .11 —.01 2.8 2.2 —1.7 Increase for nitrogen 4.8 5.5 14.2 5.1 —(.30) (.25) —3.5 .9 —.8 ’The figures in parentheses in these columns represent bushels of seed; the others, tons of hay. series, and grass strips about two rods wide between the series and surround- ing the experiment field. The soil treatment for the individual plots is in- dicated in Tables 6, 7, and 8. Limestone was applied in small amount (1300 pounds per acre) to the first fifteen plots in each series in 1904. No further application was made until the spring of 1912, when 4 tons per acre were applied to Plots 1 to 15 of Series 300. Thus far no apparent effect has been produced, but further experiment with liberal applications may show results. Plots 1 to 15 in Series 100 and 200 were given 4 tons per acre in the spring of 1913. The “residues” include the straw and corn stalks, all clover except the seed, and legume cover crops, such as cowpeas, soybeans, or vetch, seeded in the corn at the last cultivation. These are returned to certain plots in order to supply nitrogen and organic matter in a system of grain farming. This system was not fully under way on all series until 1911, as may be seen from the lower parts of Tables 6, 7, and 8, so that as yet no conclusions regarding this treatment are justified, except that it provides an abundance of organic matter. Whether the value of the clover plowed under will ultimately reap- 191S] McDonough County 17 Tabus 7 Crop Yields in Son, Experiments, Galesburg Field: Series 200 Brown silt loam prairie; upper Illinois glaciation Oats 1904 Wheat 1905 Clover 1906 Timo- thy 1907 Corn 1908 Corn 1909 Oats 1910 Clover 1911 Wheat 1912 Plot Soil treatment applied Bushels or tons per acre 201 Lime 57.5 40.5 .72 2.30 79.8 54.1 48.0 1.39 17.5 202 Residues, lime 55. C 40.0 .63 1.31 78.8 51.9 43.3 21.1 203 Manure, lime 52.5 38.5 .57 2.55 101.3 65.6 50.6 2.64 21.7 204 Cover crop, manure, lime 55.0 40.2 .63 2.73 102.7 66.8 53.0 2.32 19.6 205 Lime 67.5 42.2 1.22 2.84 86.3 54.4 44.4 2.29 18.2 206 Lime, phosphorus 62.5 41.3 1.36 3.27 99.6 59.1 55.5 2.42 27.3 207 Residues, lime, phos- phorus. . 57.5 42.2 .90 1.79 105.6 49.4 48.6 27.3 208 Manure, lime, phos- phorus 60.0 40.0 .91 3.18 106.6 69.8 58.6 2.30 27.3 209 Cover crop, manure, lime, phos 50.0 39.0 .91 3.16 105.8 75.7 60.3 2.03 27.8 210 Lime 57.5 37.5 .69 2.46 84.5 57.8 42.3 1.14 12.2 211 Lime, phosphorus, po- tassium 55.0 38.7 1.31 3.38 95.7 67.0 55.3 2.01 28.2 212 Residues, lime, phos- phorus, potassium . . 65.0 39.3 1.40 2.15 103.3 57.5 53.8 28.3 213 Manure, lime, phos- phorus, potassium.. 65.0 41.5 1.79 3.62 98.1 69.8 58.3 2.55 25.9 214 Cover crop, manure, lime, phos., potas. . . 62.5 40.7 1.51 3.48 102.8 73.3 62.8 2.46 25.3 215 Lime 60.0 35.5 .83 2.33 84.1 58.2 41.6 .98 8.8 216 Residues 72.5 37.0 .82 1.37 87.3 54.8 38.6 11.8 217 Residues, phosphorus. . 57.5 38.7 .85 1.44 98.6 49.6 43.4 22.1 218 Residues, phosphorus, potassium 50.0 40.7 1.51 2.17 99.0 43.0 46.3 28.3 219 Residues, lime, nitro- gen, phos., potas. . . . 57.5 37.7 1.21 1.98 109.6 47.2 57.2 27.3 220 None 55.0 39.5 .71 2.49 88.3 49.5 38.1 1.00 15.6 Increase for residues —3.1 —1.70 0.0 Increase for manure 7.7 8.3 2.9 .56 .6 Increase for phosphorus -3.0 .7 .21 .41 12.0 2.0 7.3 — .17 7.7 Increase for potassium 2.0 _ .1 .52 .39 —3.5 1.4 2.0 .09 .8 Increase for nitrogen 7.5 —3.0 —.30 — .19 10.6 4.2 10.9 —1.0 pear in subsequent yields of grain and seed, must be determined by the further accumulation of data. 1 Farm manure is applied to certain plots (see tables) in proportion to their previous average crop yields ; that is, as many tons of manure are ap- plied to each plot as there were average tons of air-dry produce removed from the corresponding plots during the previous rotation, but no manure A . lsike ’ mammoth, and sweet clover promise to yield the better returns in seed altho in some cases seed has been threshed from both the first and second cuttings of the red clover. It is quite possible that better average results would be secured by regularly removing the first cutting of red clover, with the purpose of threshing it for seed, as well as the second cutting if found advisable. Some splendid seed crops have been secured from the second cutting when the first was clipped and left on the land, but under other seasonal conditions the second crop has been a failure. In such cases, altho the apparent effect is a total loss of the clover crop, at least part of this loSS is recover . ed in subsequent crops of grain. It should never be forgotten the P ur P° se this system is to enable the grain farmer to maintain the fer- tility of his soil, even tho some other system which he may not be prepared to adout might be more profitable. F 13 Soil Report No. 7 [September, Table 8.— Crop Yields in Soil Experiments, Galesburg Field: Series 300 Brown silt loam prairie; upper Illinois glaciation Tim- othy 1904 Tim- othy 1905 Corn 1906 Corn] 1907 Oats 1908 Wheat 1909 Wheat 1910 Clover 1911 Corn 1912 Plot Soil treatment applied Bushels or tons per acre 301 Lime 1.36 1.54 66.8 75.9 28.6 31.7 16.2 2.17 70.8 302 Residues, lime 1.38 1.59 68.6 77.7 26.6 33.8 19.4 89.6 303 Manure, lime 1.30 1.92 72.0 80.3 28.3 36.3 19.6 2.57 104.3 304 Cover crop, manure, lime 1.38 2.02 75.6 83.1 26.1 40.4 22.3 2.03 103.3 305 Lime 1.20 1.75 70.5 78.3 22.5 36.6 21.2 1.83 92.1 306 Lime, phosphorus 1.21 1.65 69.7 84.4 32.7 40.6 22.2 2.64 98.2 307 Res., lime, phosphorus 1.16 1.55 74.0 84.1 27.5 41.2 24.1 103.2 308 Manure, lime, phos- phorus 1.25 1.63 73.9 86.1 33.9 39.7 21,6 3.25 107.9 309 Cover crop, manure, lime, phosphorus... 1.55 2.03 83.9 87.8 28.9 44.9 24.9 3.13 106.0 310 Lime 1.75 2.25 84.3 85.6 31.6 39.8 22.4 2.74 93.0 311 Lime, phosphorus, po- tassium 2.10 2.41 86.9 87.8 32.3 44.3 24.5 3.59 101.9 312 Residues, lime, phos- phorus, potassium.. 1.55 1.91 75.8 81.2 25.9 41.8 23.2 98.4 313 Manure, lime, phos- phorus, potassium. . 1.16 1.53 68.4 77.9 31.3 35.8 23.0 3.28 108.8 314 Cover crop, manure, lime, phos., potas. . . 1.50 1.52 70.6 81.7 27.7 42.0 23.1 3.57 106.9 315 Lime 1.90 1.97 74.1 85.1 30.6 36.8 21.6 2.47 90.6 316 Residues 1.82 1.82 67.7 80.6 26.7 34.2 22 9 82.1 317 Residues, phosphorus. 1.95 2.00 59.1 83.3 31.1 44.9 27.0 99.2 318 Residues, phosphorus, potassium 2.65 2.18 66.8 73.6 25.8 43.3 29.1 113.2 319 Residues, lime, nitro- gen, phos., potas. . . . 4.15 2.37 71.2 84.7 32.7 43.8 24.9 104.1 320 None 1.46 1.56 59.6 72.8 31.3 28.5 15.8 1.46 | 79.1 Increase for residues —2.46 5.8 Increase for manure 16.7 Increase for phosphorus .01 -.05 1.2 5.1 4.8 6.0 2.9 .86 8.6 Increase for potassium .37 .14 A - 6 —4.7 2.2 -.8 .6 .47 2.9 Increase for nitrogen.. 1.50 .19 4.4 11.1 6.9 .5 -4.2 -9.1 was used until crops had been grown for four years and the data had been thus accumulated from which to compute the proper applications of manure. The live-stock system was not fully under way on all series until 1912 (see lower parts of tables), when the average increase from the manure varied from bushel of wheat to nearly 17 bushels of corn. On Plots 4, 9, and 14 cover crops are grown as indicated in the tables, but the results thus far secured do not justify advising this practice, as may be seen by comparing these plots -with Plots 3, 8, and 13, respectively. At the beginning of this experiment this field was all in timothy sod. Series 300 was not broken during the first two years, but ^4 ton of raw rock phosphate per acre was applied as top-dressing. This produced practically no effect, — a result to be expected. A ton of phosphate per acre applied to Series 200 produced no effect on the oats seeded on timothy sod in 1904 and but little effect on the wheat which followed in 1905. Beginning with Series 100 in 1904, Series 300 in 1906, and Series 200 in 1908, the regular plan has been to apply 1 >4 tons of raw rock phosphate (375 pounds of phosphorus) per acre every six years /before plowing for corn, in addition to the partial applications made as stated above. This plan has been followed essentially, 1918 ] McDonough County 19 and will be continued until the phosphorus content of the plowed soil is at least doubled, but ultimately the amounts applied for each rotation will be reduced to supply only about as much as is removed in the crops grown, and of course the annual expense for this element will then decrease accordingly. Potassium is applied in the form of potassium sulfate, ioo pounds per acre of the sulfate (containing 42 pounds of potassium) being used for each year in the rotation. The application is made only in connection with the phosphate in order to ascertain whether its use in this way is profitable, there being no doubt that it would be unprofitable if used alone. In order to help settle the question whether commercial nitrogen could be used with profit, Plot 19 in each series has received nitrogen at the rate of 25 pounds per acre per annum. Nearly the total amount for the first four years was applied in 1904, but since 1907 the applications have been made annually. The nitrogen has been applied in addition to crop residues, phos- phorus, potassium, and limestone. Table 9.— Galesburg Experiment Field: Financial Statement (Value of increase from three acres) Series 100. . . . Series 200 Series 300 Years Corn Oats Grass 1904 Corn Wheat Grass 1905 Oats Clover Corn 1906 Wheat Grass Corn 1907 Clover Corn Oats 1908 Grass Corn Wheat 1909 Corn Oats Wheat 1910 Corn Clover Clover 1911 Oats Wheat Corn 1912 Aver- age 1907 to 1912 For residues . . For manure. . . For phosph’r’s For potassium For nitrogen. . $ 1.33 5.06 12.93 $ 3.93 3.67 .97 $2.70 3.41 4.00 $6 77 .14 6.31 $-13.14' 2.70' 7.20 -1.22 3.98 $-5.34' 2.90' 7.42 -.13 3.32 $ 1.13 2 3.57 8 4.85 2.00 -.90 $-23 . 46 5.25 2 6.14 4.13 .31 $ -.16 8.16 11.49 1.06 -4.12 $7.31 1.00 1.48 'One crop only. ! Two crops only. In Table 9 is given a financial summary of the results thus far secured from the Galesburg field. Three facts are clearly brought out by the data : First . — Commercial nitrogen at 15 cents a pound has never paid its cost, and as the system of providing “home-grown” nitrogen in crop residues has developed, the effect of commercial nitrogen has decreased, so that as an average of the last five years it has paid back only 4 percent of its annual cost. Second. — Potassium, likewise, has never paid its cost, but during the early years, when no adequate provision was made for decaying organic matter, the soluble potassium salt produced a very marked effect, due in part, no doubt, to the fact that it helped to dissolve and make available the raw phosphate always applied with it. With the subsequent increase in decaying organic matter, the effect of potassium has been greatly reduced. As an average of the last six years, potassium costing $7.50 has paid back only $1. Third .- — Phosphorus applied in fine-ground natural rock phosphate in part as top-dressing, and with no adequate provision for decaying organic matter, paid only 47 percent on the investment as an average of the first three years. But it should be kept in mind that the word investment is here used in its proper sense, for the phosphorus that was removed in the in- crease produced was less than 2 percent of the amount applied, and that re- moved in the total crops, less than one-third. During the last six years, however, the phosphorus has paid 130 percent on the investment, even tho two-thirds of the application remains to positively enrich the soil. 20 Soil Report No. 7 [September, The results from the Galesburg experiment field furnish some interest- ing and valuable illustrations of the danger of drawing incorrect conclusions from field-culture experiments conducted for a short time only and without comprehensive knowledge of the factors involved. Thus, the first year the effect of potassium ($5.06) was four times, and that of nitrogen ($12.93) ten times as great as the effect of phosphorus ($1.33) ; whereas in the last year the effect of phosphorus ($11.49) was eleven times that of potassium ($1.06), while commercial nitrogen applied in addition to the crop residues appears to have been detrimental. These facts only support the following statement quoted on page 208 of Bulletin 123, “The Fertility in Illinois Soils” : “In considering the general subject of culture experiments for determining fertilizer needs, emphasis must be laid on the fact that such experiments should never be accepted as the sole guide in determining future agricultural practice. If the culture experiments and the ultimate chemical analysis of the soil agree in the deficiency of any plant-food element, then the information is conclusive and final; but if these two sources of information disagree, then the culture experiments should be considered as tentative and likely to give way with increasing knowledge and improved methods to the information based on chem- ical analysis, which is absolute.” 1 The Subsurface and Subsoil In Tables 10 and 11 are recorded the amounts of plant food in the sub- surface and the subsoil strata of the McDonough county soils, but it should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important information contained in these tables is that the upland timber soils are usually more strongly acid in the sub- surface and the subsoil than in the surface. This emphasizes the importance of having plenty of limestone in the surface soil to neutralize the acid mois- ture that rises from the lower strata by capillary action during times of partial drouth, which are critical periods in the life of such plants as clover. Thus, while the common brown silt loam prairie soil is practically neutral, the upland timber soil of similar topography is already in need of limestone ; and, as already explained, it is much more deficient in phosphorus and nitro- gen than is the common prairie soil. 'Taken from “Culture Experiments for Determining Fertilizer Needs,” by C. G. H. in"Cyclopedia of American Agriculture, Volume I, page 475. McDonough County 21 1913] Table 10.— Fertility in the Soils of McDonough County Average pounds per acre in 4 million pounds of subsurface soil (about 6% to 20 inches) Soil type No. Soil type Total organic carbon Total nitro- gen Total phos- phorus Total potas- sium Total magne- sium Total cal- cium Lime- Lame- stone stone present requir'd Upland Prairie Soils 526 Brown silt loam 68 172 5 896 1 956 67 664 22 968 21 464 200 520 Black clay loam 93 120 7 467 2 693 59 987 26 133 35 413 40 528 Brown-gray silt loam on tight clay 45 320 3 920 1 600 65 000 17 440 IS 880 160 525.1 Black silt loam on clay 68 080 5 480 1 880 62 920 25 840 28 400 80 Upland Timber Soils Yellow-gray silt loam . 17 510 2 150 1 420 72 720 20 200 15 090 750 Y ellow silt loam 13 520 1 960 1 700 75 620 23 640 14 640 2 190 Light gray silt loam on tight clay 9 680 1 680 1 680 72 840 21 280 14 000 6 880 Swamp and Bottom-Land Soils 1326 1 Deep brown silt 1 I loam. . .... 58 920 | 6 040 3 040 I 74 840 | 19 080 20 240 | 80 Table 11. — Fertility of the Soils of McDonough County Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil Total Total Total Total Total Total calcium Lime- Lime- type Soil type organic nitro- phos- potas- magne- stone stone No. carbon gen phorus sium sium present requir’d Upland Prairie Soils 526 Brown silt loam 38 430 4 056 2 520 99 246 47 874 34 284 432 520 Black clay loam 45 660 3 580 3 360 93 560 45 100 47 600 4 240 528 Brown-gray silt loam on tight clay 32 160 3 480 2 460 91 500 42 180 30 060 240 525.1 Black silt loam on clay 16 560 2 700 2 520 97 380 46 380 40 740 60 Upland Timber Soils 534 Y ellow-gray silt loam 16 590 2 550 2 520 105 090 39 630 21 465 6 495 535 Yellow silt loam 4 860 2 130 3 030 114 300 41 640 27 000 3 750 532 Light gray silt loam on tight clay 5 160 2 520 2 940 106 860 44 940 25 740 4 620 Swamp and Bottom-Land Soils 1326 Deep brown silt loam 25 260 2 940 4 620 108 780 27 360 18 780 16 800 22 Soil Report No. 7 [September, INDIVIDUAL SOIL TYPES (a) Upland Prairie Soils The upland prairie soils of McDonough county comprize 374 square miles, or 65 percent of the entire area of the county. They are usually dark in color owing to their large organic-matter content. The accumulation of organic matter in the prairie soils is due to the growth of prairie grasses that once covered them, and whose network of roots has been protected from complete decay by .the imperfect aeration afforded by the covering of fine soil material and the moisture it contains. On the native prairies, the tops of these grasses were usually burned or became almost com- pletely decayed. From a sample of virgin sod of “blue stem,” one of the most common prairie grasses, it has been determined that an acre of this soil to a depth of 7 inches contained 13% tons °f roots. Many of these roots died each year and by partial decay formed the humus of these dark prairie soils. Brown Silt Loam (526) The brown silt loam is the most important as well as the most extensive type of soil in McDonough county. It covers an area of 318.18 square miles (203,637 acres), or 55.44 percent of the entire area of the county. This type is generally sufficiently rolling for fair natural surface drain- age, altho there are some exceptions where the land is so flat as to require thoro artificial drainage. Draws or swales are frequently “seepy.” To carry off this seepage from the higher land, there should be at least one line of tile, and two may sometimes be necessary. The surface soil, o to 6^3 inches, is a brown silt loam varying from a yellowish brown on the more rolling areas to a dark brown or black on the more nearly level and poorly-drained areas. In physical composition it varies to some extent, but it normally contains 70 to 80 percent of the different grades of silt. The clay content, usually 10 to 12 percent, increases as the type approaches black clay loam (520) and black silt loam on clay (525.1), nat- urally becoming greater in the poorly-drained areas. The sand content varies from 8 to 20 percent and is usually of the finer grades. The organic-matter varies from 3 to 5 percent, averaging 4.2 percent, or 42 tons per acre. Where this type passes into the brown-gray silt loam on tight clay (528) or the yellow-gray silt loam (534), the amount of organic matter becomes lower. The forest trees that once grew on the upland in this climate reduced the or- ganic matter and ultimately changed the original brown prairie soil into yellow- gray silt loam. These forests consisted quite largely of black walnut, with such other trees as wild cherry, hackberry, ash, and elm. A black-walnut soil is generally recognized by farmers as being one of the best timber soils. It still contains, as a rule, a large amount of the organic matter that accumu- lated from the prairie grasses. The subsurface is represented by a stratum varying from 5 to 14 inches in thickness. This variation is due to changing topography, the stratum be- ing thinner on the more rolling areas and thicker on the level areas. In phy- sical composition the subsurface varies the same as the surface soil, but it usually contains a slightly larger amount of clay and a much smaller amount of organic matter. In some places, it may become quite heavy, as where the brown silt loam grades toward the black silt loam on clay (525.1). In color 1M3\ McDonough County 23 the subsurface varies from a dark brown or almost black to a light or a yel- lowish brown. It usually becomes lighter with depth and passes into the yellow subsoil. The natural subsoil begins 12 to 21 inches beneath the surface and ex- tends to an indefinite depth, but it is usually sampled to a depth of 40 inches. It varies from a yellow to a drabbish yellow, clayey silt. In the level or nearly level areas, it is of a drab color, while in the more rolling areas, where better drainage has allowed higher oxidation of the iron to take place, it is of a yellow or brownish yellow color. The upper part of the subsoil usually contains more clay than the lower part. The subsoil is usually pervious to water, permitting good drainage, but where this type grades toward brown-gray silt loam on tight clay (528), a phase is found that is rather hard to drain. While this type is in fair physical condition, yet continuous cropping to corn, or corn and oats, with the burning of the stalks, is destroying the tilth ; the soil is becoming more difficult to work; it runs together more; and aeration, granulation, and absorption of moisture do not take place as readily as formerly. This condition of poor tilth may become serious if the present methods of management continue; it is already one of the factors that limit the crop yields. The remedy is to increase the organic-matter content by plowing under crop residues, such as corn stalks, straw, and clover, instead of selling them from the farm or burning them, as is so often practiced at present. Where corn follows corn, the stalks should be thorolv cut up with a sharp disk or stalk cutter, and turned under. Likewise, the straw should be returned to the land in some practical way, either directly or in manure. Clover should be one of the crops grown in the rotation, and it should be plowed under directly or in manure instead of being sold as hay, except when manure can be brought back. The addition of fresh organic matter is not only of great value in im- proving the physical condition of this type of soil, but it is of even greater importance because of its nitrogen content and because of its power, as it ■decays, to liberate potassium from the inexhaustible supply in the soil, and phosphorus from the phosphate contained in or applied to the soil. For permanent profitable systems of farming on brown silt loam, phos- phorus should be applied liberally, and sufficient organic matter should be provided to furnish the necessary amount of nitrogen. On the ordinary type, limestone is already becoming deficient. In live-stock farming an application of two tons of limestone and one-half ton of fine-ground rock phosphate per acre every four years, with the return to the soil of all manure made from a rotation of corn, corn, oats, and clover, will maintain the fertility of this type, altho heavier applications of phosphate may well be made during the first two or three rotations. If grain farming is practiced, the rotation may be wheat, corn, oats, and clover, with an extra seeding of clover as a cover crop in the wheat, to be plowed under late in the fall or in the following spring for corn; and most of the crop residues, with all clover except the seed, should also be plowed under. In either system, alfalfa may be grown on a fifth field and moved every five years, the hay being fed or sold. (For re- sults of field experiment on the brown silt loam prairie, see Tables 3 to 9.) 24 Soil Eepoet No. 7 [. September , Black Clay Loam (520) The black clay loam represents in part the originally swampy and poorly- drained land (the flat prairie) of the upper Illinois glaciation. It is frequently called “gumbo” because of its sticky character. Its formation in the low places is due to the accumulation of organic matter and the washing in of clay and fine silt from the slightly higher adjoining lands. This type in McDon- ough county covers 19.22 square miles (12,301 acres), or 3.35 percent of the total area of the county. In topography it is so flat that in the large areas the problem of getting a sufficient outlet for drainage has caused some dif- ficulty. The surface stratum is a black, granular, clay loam with an average or- ganic-matter content of 6.75 percent, or 67 tons per acre, the amount varying from 60 to 80 tons. The more luxuriant growth of prairie grasses that once covered this black clay loam, and the preservation of their roots by the moist condition of the soil, has resulted in a greater accumulation of organic matter in this type than in the more rolling types of upland prairie soils. The surface soil is naturally quite granular. This property of granula- tion is important to all soils, but especially so to heavy ones, for by it the soil is kept in good tilth and rendered pervious to air and water. If the granules are destroyed by puddling (as they are if the soil is worked or stock are allowed to trample on it while it is wet), they will be formed again by freezing and thawing or by moisture changes (wetting and drying). These natural agencies produce “slaking,” as the process is usually termed. If, however, the organic-matter or the lime content becomes low, this tendency to granulate grows less and the soil becomes more difficult to work. The subsurface extends to a depth of 10 to 16 inches below the surface stratum. It differs from the surface in color, becoming lighter with depth, the lower part of the stratum passing into a drab or yellowish, silty clay. It is quite pervious to water, owing to the jointing or checking produced by shrinkage in times of drouth. The amount of organic matter varies from 3.8 to 4.6 percent. The subsoil is usually a drab or dull yellow, silty clay, but locally it may be a yellow, clayey silt or even a silt. As a rule, the iron is not highly ox- idized, because of poor drainage. The checking and jointing in the subsoil make it readily permeable to water and consequently easy to drain. In some areas the subsoil contains large numbers of limestone concretions (calcium carbonate). Black clay loam presents many variations. Here, as elsewhere, the bound- ary lines between different soil types are not always distinct, but types fre- quently pass from one to another very gradually, thus giving an interme- diate zone of greater or less width. Variations between black clay loam (520) and brown silt loam (526) are very likely to occur since they are usually adjoining types. This gives a lighter phase of black clay loam (520), with a smaller organic-matter content than the average, or a heavier phase of brown silt loam (526), darker, and with a larger amount of organic matter than the average. (In chemical composition, the gradation zone is inter- mediate between the two normal, adjoining types.) Again, in some areas of black clay loam there has been enough silty material washed in from the surrounding higher lands, especially near the edges of the areas, to modify the character of the surface soil. This change is taking place more rapidly now, with the annual cultivation of the soil, than formerly, when washing was largely prevented by prairie grasses. 1913 ] McDonough County 25 Drainage is the first requirement of this type. Altho it usually has but little slope, yet because of its perviousness it affords a good chance for tile drainage. Keeping the soil in good physical condition is very essential, and thoro drainage helps to do this to a great extent. As the organic matter is destroyed by cultivation and nitrification and the lime removed by cropping and leaching, the physical condition of the soil becomes poorer, and conse- quently it becomes more difficult to work. Both the organic matter and the lime tend naturally to develop a granular condition, but they are especially effective when aided by careful and well-timed cultivation. The organic matter should be maintained by turning under manure, clover, and crop residues, such as corn stalks and straw. Too often the crop residues are burned or put back in such a way as not to produce the greatest benefit. Straw is too frequently left in lots until the larger part of the organic matter is lost by fermentation and leaching. Ground limestone applied liberally when the soil becomes acid, will also help to keep the soil in good physical condition. While black clay loam is one of the best soils in the state, the clay and humus contained in it give it the property of shrinkage and expansion to such a degree as to be somewhat objectionable at times. When the soil is wet, these constituents expand, and when the moisture evaporates or is used by crops, they shrink. This results in the formation of cracks up to two inches or more in width and extending with lessening width to a foot or more in depth. These cracks allow the soil strata to dry out rapidly, and as a result, the crop is injured thru lack of moisture. They may also do considerable damage by “blocking out” hills of corn and severing the roots. While crack- ing may not be prevented entirely, yet good tilth, with a soil mulch, will do much toward that end. This type is fairly well supplied with plant food, which is usually liber- ated with sufficient rapidity by a good rotation and by the addition of mod- erate amounts of organic matter. The amount of organic matter added must be increased, of course, with continued farming, until the nitrogen supplied is equal to that removed. Altho the addition of phosphorus is not expected to produce marked profit, it is likely to pay its cost in the second or third rotation, and even by maintaining the productive power of the land, the capital invested is protected. This type is rich in magnesium and calcium, and the subsoil usually con- tains plenty of carbonates. With continued cropping and leaching, applica- tions of limestone will be needed. (No field experiments have been conducted as yet on this type of soil.) Brown-Gray Silt Loam on Tight Clay (528) Brown-gray silt loam on tight clay is found principally in the southwest part of McDonough county. It comprizes 29.25 square miles (18,720 acres), or 5.1 percent of the total area. The surface soil, o to 6% inches, is a brown or grayish brown silt loam containing some fine sand and coarse silt, which give it a fine texture. The organic-matter content varies somewhat according to the relation of the type to other types, being greater where it approaches brown silt loam (526) or black silt loam on clay (525.1), and less where it grades toward yellow-gray silt loam (534) ; the average is about 3.5 percent. The subsurface is represented by a stratum 10 to 12 inches thick. In color it varies from a brown to a gray or grayish brown, the upper part of 26 moil Report No. 7 [September, the stratum usually being brown, and the lower part, gray or grayish brown. It differs from the surface stratum principally in the amount of organic matter it contains. The natural subsoil consists of a stratum of tight clay beginning 16 to 18 inches beneath the surface and varying in thickness from io to 20 inches. It is usually underlain by a pervious silt. This type is rather flat, and much of it needs drainage. Owing to the impervious character of the subsoil, it is in greater need of tile drainage than is the brown silt loam, and the lines of tile should be placed nearer each other. For efficient drainage, they should not be over 5 rods apart, and 3 or 4 rods is better. Care should be taken to increase the amount of organic matter by the proper rotation 6f crops, by turning under crop residues, and by the application of farm manure. Deep-rooting crops, such as red, mam- moth, or sweet clover, should be grown in order to loosen up, in a measure, the tight clay subsoil and promote drainage and aeration. From Table 2 it will be seen that the surface soil contains only 900 pounds of phosphorus per acre. To increase the amount of this element, lib- eral applications of fine-ground rock phosphate should be made in connection with the decaying organic matter, as on the brown silt loam. Limestone should be applied at the rate of 2 to 3 tons per acre every four to six years. The initial application may well be 1 ton of phosphate and 4 tons of limestone. On recently established twenty-acre experiment fields on this type of soil at Carthage in Hancock county and at Clayton in Adams county, organic manures increased the yield of corn, in the very dry season of 1912, from 30.6 to 40.5 bushels at Carthage and from 36.8 to 46.7 bushels at Clayton. Where both organic manures and rock phosphate were applied, the average yield on the Carthage field was increased to 48.1 bushels and on the Clayton field to 55.6 bushels. Thus it is seen that the average increase in the corn yield resulting from the use of organic manures was 9.9 bushels per acre, and from the use of organic manures reinforced with rock phosphate, 18.2 bushels. Limestone applied subsequently is showing marked benefit in 1913 at both Carthage and Clayton, especially on the growth of sweet clover, which is used as a green-manure cover crop. Thus the data already secured are in agreement with the analytical data for this soil type. Black Silt Loam on Clay (525.1) Black silt loam on clay comprizes 7.24 square miles (4,634 acres), or 1.26 percent of the area of McDonough county. It occurs mostly in small areas over the county, often in proximity to the brown-gray silt loam on tight clay (528). In topography it is usually about the same as the black clay loam (520), but it does not permit of as good underdrainage because of the some- what tight character of the subsoil. This is especially true where it ap- proaches the brown-gray silt loam on tight clay (528). The surface soil, o to 6^3 inches, is a black silt loam, varying on the one hand toward black clay loam (520), and on the other to brown silt loam (526) or brown-gray silt loam on tight clay (528). When thoroly drained, it is naturally granular and of good tilth, but the same precautions must be taken to keep it in good physical condition as are necessary with black clay loam (520). The organic-matter content averages about 5.5 percent, or 55 tons per acre. 1913] McDonough County The subsurface stratum varies from 8 to 14 inches in thickness. In color it varies from black to dark brown near the top of the stratum, to drab or yellowish drab near the bottom. The proportion of clay increases with depth. The subsoil resembles that of the black clay loam (520) except that it is heavier. Drainage is one of the first requirements of this type. For maintaining good tilth one of the most practical means is the incor- poration of organic matter. This can be accomplished by providing a proper rotation of crops (which should include clover or some other legume), and turning under the legume, together with the crop residues (corn stalks and straw). Such organic matter or farm manure will not only help in maintain- ing good tilth but it will also supply the 'amount of nitrogen required in per- manent economic systems of general farming. In phosphorus content, black silt loam on clay lies between the brown silt loam and the brown-gray silt loam on tight clay. Fine-ground rock phosphate should be applied in connection with the organic manures at the rate of about one-half ton per acre every four years. The initial application may well be one ton or more. This type of soil is practically neutral, which means that it is not dis- tinctly acid and yet that it contains no limestone. For the best results, es- pecially in the growing of legume crops, limestone should be applied. Two tons per acre every four or five years will maintain a sufficient supply in the soil. (b) Upland Timber Soils In the soils of the upland forests, there is found no such quantity of roots as is found in the prairie soils. The vegetable material consists of leaves and twigs which fall upon the surface and either are burned by forest fires or un- dergo almost complete decay. There is very little chance for these to become mixed with the soil. As a result, the organic-matter content of the upland timber soils has been lowered until in some parts of the state a low condi- tion of apparent equilibrium has been reached. Yellow-Gray Silt Loam (534) Yellow-gray silt loam in McDonough county occurs in the outer timber belts along the streams, and covers 39 square miles (24,960 acres), or 6.79 percent of the county. In topography it is sufficiently rolling for good sur- face drainage and without much tendency to wash if proper care is taken. The surface soil, o to 6^3 inches, is a gray to yellowish gray silt loam, incoherent and mealy but not granular. The amount of organic matter con- tained in it varies from 1.8 to 3.4 percent with an average of 2.3 percent or 23 tons per acre. This variation is due to the relation of the type to other types, the content of organic matter increasing where it grades into brown silt loam (526) and brown-gray silt loam on tight clay (528), and decreasing where it passes into yellow silt loam (535) and light gray silt loam on tight clay (532). In some places, erosion has reduced the amount of organic matter. The subsurface stratum varies from 3 to 10 inches in thickness, erosion having reduced its depth on the more rolling areas. In color it is a gray, grayish yellow, or yellow silt loam, somewhat pulverulent, but becoming more coherent and plastic with depth. 28 Soil Eepoet No. 7 [September, The subsoil is a yellow or grayish yellow, clayey silt or silty clay, some- what plastic when wet, but friable when only moist, and pervious to water. In the management of this yellow-gray silt loam, one of the most es- sential points is the maintenance or increase of organic matter. This is nec- essary in order to supply nitrogen and liberate mineral plant food, to give better tilth, to prevent “running together,” and, on some of the more rolling phases, to prevent washing. Another essential is the neutralization of the acidity of the soil by the application of ground limestone, so that clover, alfalfa, and other legumes may be grown more successfully. The initial ap- plication may well be 4 or 5 tons per acre, after which 2 tons per acre every four or five years will be sufficient. Since the soil is poor in phosphorus, this element should be applied, preferably in connection with farm manure or clover plowed under. In permanent systems of farming, fine-ground nat- ural rock phosphate will be found the most economical form in which to sup- ply the phosphorus. For definite results from the most practical field experiments upon typical vellow-gray silt loam, we must go down into “Egypt,” where the people of Saline county, especially those in the vicinity of Raleigh and Galatia, have provided the University with a very suitable tract of this type of soil for a permanent experiment field. There, as an average of triplicate tests each year, the yield of corn on untreated land was 25.3 bushels in 1910, 23.6 bushels in 1911, and 22 bushels in 1912; while on duplicate plots treated with heavy applications of limestone and a limited amount of organic manures, the cor- responding yields were 41.4 bushels in 1910, 41.3 bushels in 1911, and 50.1 bushels in 1912, the corn being grown on a different series of plots every year in a four-year rotation of wheat, corn, oats, and clover. About the same proportionate increases were produced in wheat and hay, and the effect on oats was also marked. Owing to the low supply of organic matter, phos- phorus produced no benefit, as an average, during the first two years; but with increasing applications of organic matter, the effect of phosphorus is seen in the crops of 1912 and 1913. Of course a single four-year rotation cannot be practiced in less than four years, and the full benefit of a system of rotation and soil treatment is not to be expected before the third or fourth four-year period. While limestone is the material first needed for the economic improve- ment of the more acid soils of southern Illinois, with organic manures and phosphorus to follow in order, the less acid soils of the west-central part of the state are first in need of phosphorus, in which they are relatively about as deficient as the acid soils are in lime. Organic matter is also greatly needed by these less acid soils. Table 12 shows in detail eleven years’ results secured from the Antioch soil experiment field located in Lake county on the yellow-gray silt loam of the late Wisconsin glaciation. In acidity, this type in McDonough county is intermediate between the similar soils in Saline and Lake counties, but no experiment field has been conducted on this important soil type in the upper Illinois glaciation, in which McDonough county is situated. The Antioch field was started in order to learn as quickly as possible just what effect would be produced by the addition to this type of soil, of nitrogen, phosphorus, and potassium, singly and in combination. These elements have all been added in commercial form. Only a small amount of lime was ap- plied at the beginning; and with the abnormality of Plot 101, and with an abundance of limestone in the subsoil (a common condition in the late Wis- 191S ] McDt -jouqh County 29 Table 12.— Crop Yields in Soil Experiments, Antioch Field Yellow-gray silt loam, undulating timber- land; late Wisconsin glaciation Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Corn 1906 Corn 1907 Oats 1908 Wheat 1909 Corn 1910 Corn 1911 | Oats 1912 Plot Soil treatment applied Bushels per acre 101 None 1 44.8 36.6 17.8 18.5 35.9 12.4 65.6 12.2 5.2 34.4 21.3 102 Eime 45.1 38.9 12.8 10.3 31.5 9.5 61.6 11.7 3.0 24.6 17.5 103 Lime, nitrogen . . . 46.3 40.8 2.8 17.8 37.8 6.4 60.3 13.0 1.4 10.4 24.4 104 Time, phosphorus 50.1 53.6 12.5 35.8 57.4 13.4 70.9 23.3 6.8 37.4 49.1 105 Eime, potassium.. 48.2 50.2 9.7 21.7 34.9 12.9 62.5 13.5 4.6 20.4 18.8 106 Lime, nitro., phos. 56.6 62.7 15.9 15.2 59.3 20.9 49.1 33.8 6.0 37.0 46.9 107 Lime, nitro. , potas. 52.1 54.9 10.3 11.8 39.0 11.1 52.6 21.0 1.6 7.0 16.9 108 Lime, phos., potas. 60.7 66.0 19.7 28.7 59.1 18.3 59.4 26.2 3.2 42.2 35.9 109 Lime, nitro., phos. potas 61.2 69.1 31.9 18.0 65.9 31.4 51.9 30.5 3.0 44.2 31.9 110 Nitro. , phos., potas. 59.7 71.8 37.2 16.3 66.3 28.8 55.9 34.5 4.0 49.0 38.1 Average Increase: Bushels per Acre For nitrogen 3.0 4.7 1.6 -8.4 4.8 3.9 -10.1 5.9 —1.4 —6.5 — .3 For phosphorus 9.2 16.7 11.1 9.0 24.6 11.0 -1.4 13.7 2.1 24.6 21.6 For potassium 6.0 11.0 6.9 .3 3.2 5.9 -3.9 2.3 —1.2 1.1 —8.6 For nitro., phos. over phos 6.5 9.1 3.4 -20.6 1.9 7.5 -21.8 10.5 — .8 — .4 2.2 For phos., nitro. over nitro 10.3 21.9 13.1 -2.6 21.5 14.5 -11.2 20.8 4.6 26.6 22.5 For potas., nitro., phos. over nitro. , phos 4.6 6.4 16.0 2.8 6.6 10.5 2.8 —3.3 —3.0 7.2 -15.0 Value of Crops per Acre in Eleven Years Plot Soil treatment applied Total value of eleven crops Value of increase 101 None $112.16 102 96.38 £— 15.78 103 104 Lime, nitrogen Lime, phosphorus 97.89 157.67 —14.27 45.51 105 L/ime, potassium 111.86 — .30 106 Lime, nitrogen, phosphorus.. 152.75 40.59 107 Lime, nitrogen, potassium 104.89 —7.27 108 Lime, phosphorus, potassium 160.25 48.09 109 Lime, nitrogen, phosphorus, potassium 164.83 52.67 110 Nitrogen, phosphorus, potassium 172.78 60.62 Value of Increase per Acre in Eleven Years Cost of increase For nitrogen For phosphorus For nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassium, nitrogen, and phosphorus over nitrogen and ohosohorus $ 1.51 61.29 —4.92 54.86 12.08 $165.00 27.50 165.00 27.50 27.50 ‘Plot 101, the check plot, is the lowest ground but it is well drained and is appre- ciably better land than the rest of the field. Plot 102 is a more trustworthy check plot. 30 Soil Repoet No. 7 [September, consin glaciation), no conclusions can be drawn regarding the effect of lime. As an average of 44 tests (4 each year for 11 years), liberal applications of commercial nitrogen have produced a slight decrease in crop values, phos- phorus has paid back 200 percent of its cost, while each dollar invested in potassium has brought back only 34 cents ( a net loss of 66 percent). Thus, while the detailed data show great variation, owing both to some irregularity of soil and to some very abnormal seasons, with three almost complete crop failures (1904, 1907, and 1910), yet the general summary strongly confirms the analytical data in showing the need of applying phosphorus and the profit from its use, and the loss in adding potassium. In most cases commercial nitrogen damaged the small grains by causing the crop to lodge ; but in those years when a corn yield of 40 bushels or more was secured by the application of phosphorus either alone or with potassium, then the addition of nitrogen produced an increase. From a comparison of the results from the Sibley, Bloomington, and Galesburg fields (see pages 10 to 20), we must conclude that better yields are to be secured by providing nitrogen by means of farm manure or legume crops grown in the rotation than by the use of commercial nitrogen, which is evidently too readily available, causing too rapid growth and consequent weakness of straw ; and of course the atmosphere is the most economic source of nitrogen where that element is needed for soil improvement in general farming. (See Appendix for detailed discussion of “Permanent Soil Im- provement.”) Yellow Silt Loam (535) In area, yellow silt loam stands second among the soil types of McDon- ough county, covering 144.41 square miles (92,422 acres), or 25.16 percent of the county. It occurs as the hilly and badly eroded land on the inner tim- ber belts along the streams, usually only in narrow, irregular strips, with arms extending up the small valleys. In topography it is very rolling and in most places so badly broken that it should not be cultivated because of the danger of injury from washing. The surface soil, o to 6 2 /s inches, is a yellow or yellowish gray silt loam, pulverulent and mealy. It varies a great deal, owing to recent washing. In some places the natural subsoil may be exposed. The organic-matter con- tent is about 1.9 percent. The typical subsurface varies in thickness from o to 12 inches, the varia- tion being due to the removal of all or part of the surface and subsurface. The subsoil is a compact, yellow, clayey silt. In the management of this yellow silt loam, the most important thing is to prevent general surface washing and gullying. If the land is cropped at all, a rotation should be practiced that will require a cultivated crop as little as possible and allow pasture and meadow most of the time. If tilled, the land should be plowed deeply; and contours should be followed as nearly as possible in plowing, planting, and cultivating. Furrows should not be made up and down the slopes. Every means should be employed to maintain and in- crease the organic-matter content; this will help hold the soil and keep it in good physical condition so that it will absorb a large amount of water and thus diminish the run-off. (See Circular 119, “Washing of Soils and Methods of Prevention.”) Additional treatment recommended for this yellow silt loam is the liberal use of limestone wherever cropping is practiced. This type is quite acid and 191S\ McDonough County 31 - very deficient in nitrogen ; and the limestone, by correcting the acidity of the soil, is especially beneficial to the clover grown to increase the supply of ni- trogen. Where this soil has been long cultivated and thus exposed to surface washing, it is particularly deficient in nitrogen; indeed on such lands the low supply of nitrogen is the factor that first limits the growth of grain crops. This fact is very strikingly illustrated by the results from two pot-culture experiments reported in Tables 13 and 14, and shown photographically in Plates 6 and 7. In one experiment, a large quantity of the typical worn hill soil was col- lected from two different places. 1 Each lot of soil was thoroly mixed and put in ten four-gallon jars. Ground limestone was added to all the jars except the first and last in each set, those two being retained as control or check pots. The elements nitrogen, phosphorus, and potassium were added singly and in combination, as shown in Table 13. As an average, the nitrogen applied produced a yield about eight times as large as that secured without the addition of nitrogen. While some variations Plate 6. — Wheat in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (See Table 13) Table 13.— Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (Grams per pot) Pot No. Soil treatment applied Wheat Oats 1 2 None Limestone 3 4 5 4 3 Limestone, nitrogen 26 45 4 Limestone, phosphorus 3 6 5 Limestone, potassium 3 ' 5 6 Limestone, nitrogen, phosphorus 34 38 7 Limestone, nitrogen, potassium 33 46 8 Limestone, phosphorus, potassium 2 5 9 I Limestone, nitrogen, phosphorus, potassium 34 38 10 None 3 5 Average yield with nitrogen 32 42 Average yield without nitrogen 3 5 Average gain for nitrogen 29 ~37 1 Soil for wheat pots from loess-covered unglaciated area, and that for oat pots from upper Illinois glaciation. 32 Soil Eepoet No. 7 [September, in yield are to be expected, because of differences in the individuality of seed or other uncontrolled causes, yet there is no doubting the plain lesson taught by these actual trials with growing plants. The question arises next, Where is the farmer to secure this much-needed nitrogen? To purchase it in commercial fertilizer would cost too much; indeed, under average conditions the cost of the nitrogen in such fertilizers is greater than the value of the increase in crop yields. There is no need whatever to purchase nitrogen, for the air contains an inexhaustible supply of it, which, under suitable conditions, the farmer can draw upon, not only without cost, but with profit in the getting. Clover, alfalfa, cowpeas, and soybeans are not only worth raising for their own sake, but they have the power to secure nitrogen from the atmosphere if the soil contains limestone and the proper nitrogen-fixing bacteria. In order to secure further information along this line, another experiment with pot cultures was conducted for several years with the same type of worn hill soil as that used in the former experiment. The results are reported in Table 14. To three pots (Nos. 3, 6, and 9) nitrogen was applied in commercial form, at an expense amounting to more than the total value of the crops produced. In three other pots (Nos. 2, 11, and 12) a crop of cowpeas was grown during the late summer and fall and turned under before the wheat or oats were planted. Pots 1 and 8 served for important comparisons. After the second catch crop of cowpeas had been turned under, the yield from Pot 2 exceeded that from Pot 3 ; and in the subsequent years the legume green manures pro- duced, as an average, rather better results than the commercial nitrogen. This experiment confirms that reported in Table 13, in showing the very great need of nitrogen for the improvement of this type of soil, and it also shows that nitrogen need not be purchased but that it can be obtained from the air by growing legume crops and plowing them under as green manure. Of course, the soil can be very markedly improved by feeding the legume crops to live stock and returning the resulting farm manure to the land, if sufficiently frequent crops of legumes are grown and if the farm manure produced is sufficiently abundant and is saved and applied with care. As a rule, it is not advisable to try to enrich this type of soil in phos- phorus, for with the erosion that is sure to occur to some extent, the phos- phorus supply will be renewed from the subsoil. One of the most profitable crops to grow on this land is alfalfa. To get alfalfa well started requires the liberal use of limestone, thoro inoculation with nitrogen-fixing bacteria, and a moderate application of farm manure. If manure is not available, it is well to apply about 500 pounds per acre of acid phosphate, or steamed bone meal, mix it with the soil, by disking if possible, and then plow it under. The limestone (about 5 tons) should be applied after plowing and should be mixed with the surface soil in the preparation of the seed bed. The special purpose of this treatment is to give the alfalfa a quick start in order that it may grow rapidly and thus protect the soil from washing. Light Gray Silt Loam on Tight Clay (532) Light gray silt loam on tight clay in McDonough county aggregates only 2.53 square miles (1,619 acres), or .44 percent of the county. It usually appears in small areas chiefly in the southwestern and southern part of the county. In topography this type is flat, with poor drainage, altho not swampy. It was formerly covered with hickory, white oak, and “black jack.” 191S J McDonough County 33 The surface soil, o to inches, is a white or very light gray silt loam, incoherent, friable, and porous. Iron concretions are usually present. The organic-matter content is very low, amounting to only 1.4 percent, or 14 tons per acre. The subsurface is a light gray silt loam extending to a depth of 16 to 18 inches. It becomes more clayey with depth and contains only a very small amount of organic matter. The subsoil is a tight, compact, clayey silt or silty clay. Besides being very deficient in organic matter, this type of soil contains no limestone, and consequently is in poor physical condition. It runs together badly, and does not retain moisture well, owing to the strong capillarity in the surface and subsurface strata caused by lack of organic matter. In the management of this type, ground limestone should be used liber- ally, rock phosphate should be added, and the content of organic matter should be increased in every practical way. Deep-rooting crops, such as red, mammoth, or sweet clover, will loosen the tight clay subsoil as well as supply the top soil (surface and subsurface strata) with organic matter and nitrogen. Where this type is not well drained, alsike will grow better than red clover. Crop residues should be plowed under or plenty of farm manure supplied. Pasturing is one of the best uses that can be made of this land, and even when used for this purpose it may well be liberally supplied with limestone, organic matter, and phosphorus before being seeded down. Plate 7. — Wheat in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (See Table 14) Table 14 — Crop Yields in Pot -Culture Experiment with Yellow Silt Loam oe Worn Hill Land and Nitrogen Fixing Green Manure Crops (Grams per pot) Pot No. Soil treatment 1903 Wheat 1904 Wheat 1905 Wheat 1906 Wheat 1907 Oats 1 None. 5 4 4 4 6 2 Limestone, legume 10 17 26 19 37 11 Limestone, legume, phosphorus 14 19 20 18 27 12 Limestone, legume, phosphorus, potassium 16 20 21 19 30 3 Limestone, nitrogen Limestone, nitrogen, phosphorus 17 14 15 9 28 6 26 20 18 18 30 9 Limestone, nitrogen, phosphorus, potassium 31 34 21 20 26 8 Limestone, phosphorus, potassium 3 3 5 3 7- 34 Soil Keport No. 7 [September, (c) Swamp and Bottom-Land Soils The bottom-land soils are derived from material washed from the up- land, and must therefore have some relation to the upland soils. They dif- fer in that they are more variable in physical composition than any single upland type, and the brown color extends into them to a greater depth. Deep Brown Silt Loam (1326) The bottom land in McDonough county is made up entirely of deep brown silt loam. It occurs in long, narrow strips varying from a few rods to nearly a mile in width, and occupies 14.02 square miles (8,973 acres), or 2.44 percent of the area of the county. In topography it is flat or with very slight undulations that represent old stream or overflow channels. The surface soil, o to 6^3 inches, is a brown silt loam containing 4 per- cent of organic matter, or 40 tons per acre. It is probably easier to main- tain the fertility and the organic matter in this deep brown silt loam than in the upland soils, because of its occasional overflow and the consequent deposition of material rich in humus and plant food. In physical composi- tion this type varies from a clay loam to a sandy loam, but the areas of these extreme types, especially of the sandy loam, are so small and so changeable that to show them on the map really does not mean very much, as the next flood may change their boundaries. The subsurface is also a brown silt loam, becoming lighter in color, and frequently in texture, with depth. It contains an average of 2.5 percent of organic matter. The subsoil is a yellowish drab silt loam, varying in physical composition either to a clayey silt or to a sandy loam, or even to a sand in the lower sub- soil. Where proper drainage is secured, this type is quite productive. As a rule, where it is subject to frequent overflow nothing is needed except good farming. Even the systematic rotation of crops is not so important where the land is subject to occasional overflow, but where it lies high or is pro- tected from overflow by dikes, a rotation including legume crops should be practiced, and ultimately provision should be made for the enrichment of such protected land in both phosphorus and organic matter, and if acid, in limestone. 191S] McDonough County 35 APPENDIX A study of the soil map and the tabular statements concerning crop re- quirements, the plant-food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil improvement, and a careful study of the discussion of general prin- ciples and of the descriptions of individual soil types, will furnish the most necessary and useful information for the practical improvement and perma- nent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and impor- tant soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility in Illinois Soils,” which contains a colored gen- eral survey soil map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils” Bulletin No. 94, “Nitrogen Bacteria and Legumes” Bulletin No. 115, “Soil Improvement for the Worn Hill Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois” Circular No. no, “Ground Limestone for Acid Soils” Circular No. 127, “Shall We Use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, “Some "Results of Scientific Soil Treatment” and “Methods and Re- sults of Ten Years’ Soil Investigation in Illinois” Circular No. 165, “Shall We Use ‘Complete’ Commercial Fertilizers in the Corn Belt?” NOTE. — Information as to where to obtain limestone, phosphate, bone meal, and po- tasium salts, methods of application, etc., will also be found in Circulars no and 165. Soil Survey Methods The detail soil survey of a county consists essentially of indicating on a map the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential: first, careful, well-trained men to do the work; second, an ac- curate base map upon which to show the results of their work: and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal varia- tions and limits, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will survey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries will match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil map- ping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construction of these maps, while the most trustworthy county map avail- able is used in locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and cor- 36 Soil Repoet No. 7 [September, rected if wrongly located. In order to make these verifications and correc- tions, each survey party is provided with an odometer for measuring dis- tances, and a plane table for determining directions of roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, additional streams, and necessary corrections are placed in their proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map, and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils for this purpose being car- ried in the field. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is taken by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while dis- tances in the field off the roads are determined by pacing, an art ;n which the men become expert by practice. The soil boundaries can thus be located with as high a degree of accuracy as can be indicated by pencil on the scale of one inch to the mile. Soil Characteristics The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type grades into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, alluvial, colluvial, or cumulose; (2) the topography, or lay of the land ; (3) the native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical, or mechanical, composition of the different strata composing the soil, as the percentages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. The common soil constituents are indicated in the following outline : Constituents of Soils Organic f Comprising undecomposed and partially decayed Matter 1 vegetable material Soil Constituents Inorganic Matter Clay mm. 1 and less Silt mm. to .03 mm. Sand 03 mm. to 1. mm. Gravel mm. to 32 mm. Stones 32. , mm. and over 1 25 millimeters equal 1 inch. > Further discussion of these constituents is given in Circular 82. 1913 \ McDonough County 37 Groups op Son, Types The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand and silt and a little clay. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and some silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams— Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 15 to 50 percent of gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no agricultural value. More or less organic matter is found in nearly all the above classes. Supply and Liberation op Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop ; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which this is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly im- portant, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually present in the. soil strata sampled and analyzed, but the rate of liberation is governed by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are lime- stone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may be supplied also by green-manure crops and crop residues, such as clover, cow- peas, straw, and cornstalks. The rate of decay of organic matter depends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which represents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly 38 Soil Eepoet No. 7 [, September , 20 tons of organic matter. But this organic matter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20tons of old, inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent additions of active organic matter, whether in applications of farm manure, in legume crops, or in grass- root sods of old pastures. Probably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that with the normal rainfall of Illinois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such com- modity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts of potassium, magnesium, calcium, etc., for the use of the growing crop. , As already explained, fresh organic matter decomposes much more rap- idly than the old humus, which represents the organic residues most resistant to decay and which consequently has accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old, resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and thus furnish or liberate organic matter and inorganic food for bacteria, the bacteria, under such favorable conditions, appearing to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when incorporated with fresh farm manure; so that, when used together, two tons of the mixture may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bacterial action is also promoted by the presence of limestone. The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive 1918] McDonough County 39 condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil ; while in old, worn soils that are greatly in need of fresh, active, organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insuf- ficient; but even these plants (which include only the clovers, peas, beans, and vetches, among our common agricultural plants) secure from the soil alone six elements (phosphorus, potassium, magnesium, calcium, iron and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a building is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay; and, where the land is properly drained and properly tilled, such crops would frequently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the abso- lute needs of the crops. Crop Requirements The accompanying table shows the requirements of such crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are not known ever to limit the yield of general farm crops grown under normal conditions.) Tabus A. — Plant Food in Wheat, Corn, Oats, and Clover Produce Nitro- gen, pounds Phos- I phorus, pounds Potas- sium, pounds Magne- sium, pounds Cal- cium, pounds Kind Amount Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw 2 y z tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs % ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2 l /z tons 31 5 52 7 IS Clover seed 4 bu. 7 2 3 1 1 Clovei hay . 4 tons 160 20 120 31 117 Total in grain and seed 244 1 42 51 16 4 Total in four crops 510 1 77 322 68 168 ‘These amounts include the nitrogen contained in the clover seed or hay, which, however, may be secured from the air. Soil Eepoet No. 7 [September, 40 To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as possible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the ioo-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with limestone, phosphorus, and manure). The importance of maintaining a rich surface soil cannot be too strongly emphasized. This is well illustrated by data from the Rothamsted Experi- ment Station, the oldest in the world. Thus on Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well fertilized), but the amounts of both nitrogen and phosphorus in the. subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (o to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods of Liberating Plant Food Limestone and decaying organic matter are the principal materials the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules .on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria, which have power to transform the insoluble and unavail- able organic nitrogen into soluble and available nitrate nitrogen. At the same time, the products of this decomposition have power to dis- solve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing whatever to the soil, but always leaves the soil poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root devel- opment and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows : 1918] McDonough County 41 (i) If the soil is acid, apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC 0 3 MgC 0 3 ), which contains both calcium and magnesium and has slightly greater power to cor- rect soil acidity, ton for ton, than the ordinary calcium limestone (CaC 0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years, On strongly acid soils, or in preparing the land for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks), or by using for feed and bedding practically all the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines : First year, corn. Second year, corn. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rota- tion. In grain farming, with small grain grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five-year rotation by cutting out either the second or the sixth year, and to a four-year system by omitting the fifth and sixth years. With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover; or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are: Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat,’ (4) clover, and (5) wheat (and clover) allows legumes to be seeded four times, and alfalfa may be grown on a sixth field for five or six years in the combination rotation, alternating between two fields every five years, or rotating over all the fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute sweet clover or alsike for red clover in about every third rotation, and at the same 42 Soil Report No. 7 [ September , time to discontinue its use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover crop (seeded at the last cultivation) in the southern part of the state, and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named : I bushel of oats (grain and straw) requires i pound of nitrogen. i bushel of corn (grain and stalks) requires 1(4 pounds of nitrogen. i bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. I ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. For grain crops, such as wheat, corn, and oats, about two- thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. (See also discussion of “The Potassium Problem,” on pages below.) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in considerably* larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far se- cured shows positively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil improvement. The first application may well be one ton per acre, and subsequently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total ap- plication of from three to five or six tons per acre of raw phosphate con- taining \ 2 l / 2 percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in car- load lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phosphate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about 1 y 2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rotation, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. 1913 ] McDonough County 43 (4) Until the supply of decaying organic matter has been made ade- quate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use; of a soluble salt or mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as to furnish available potas- sium and magnesium, and for a few years such use of kainit will no doubt be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for decaying organic matter, since this will necessitate returning to the soil either all produce except the grain (in grain farming) or the manure produced in live-stock farming. (Where hay or straw is sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow- gray silt loam, and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tends to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently ; but where such lands are farmed under such a system, not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time ; and where the soil is acid a liberal use of limestone, as top-dressings if necessary, and occasional re- seeding with clovers will benefit both the pasture and indirectly the grain crops. Advantage of Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years; but even a partial stand of clover the first time will probably provide a thousand times as many bac- teria for the next clover crop as one could afford to apply in artificial inocu- lation, for a single root-tubercle may contain a million bacteria developed from one during the season’s growth. This is only one of several advantages of the second course of the rota- tion over the first course. Thus the mere practice of crop rotation is an ad- vantage, especially in helping to rid the land of insects and foul grass and weeds. The deep-rooting clover crop is an advantage to subsequent crops because of that characteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage; and in systems of permanent soil improvement, such as are here advised and illustrated, more limestone and more phosphorus are provided than are needed for the meager or moderate crops produced during the first rotation, and conse- quently the crops in the second rotation have the advantage of such accumu- lated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. This means that these systems tend positively toward the making of richer lands. The ultimate analyses recorded in the tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter: and 44 Soil Report No. 7 [September, the accumulated information from careful and long-continued investigations in different parts of the United States clearly establishes the fact that in gen- eral farming these essentials can be supplied with greatest economy and profit by the use of ground natural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applications are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt, such as kainit, is used, it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 60 years (1852 to 1911), the yield of wheat has been 12.7 bushels on un- treated land, 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied; and, as further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of mag- nesium raised it to 29.2 bushels; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied, the average wheat crop re- moved 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained an abundance of limestone, but no organic matter was provided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 60 years (1852 to 1911) has been 14.2 bushels on untreated land, 38.1 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus have been applied per acre per annum ; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.5 bushels, but, where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average has been 43.0 bushels. Thus, as an average of 60 years, the use of sodium pro- duced 1.8 bushels less wheat and 1.5 bushels more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop; but this must be expected to occur in time where no potassium is returned in straw or manure, and no provision made for liberating potassium from the supply still re- maining in the soil. If more than three-fourths of the potassium removed were returned in the straw (see Table A), and if the decomposition prod- ucts of the straw have power to liberate additional amounts of potassium from the soil, the necessity of purchasing potassium in a good system of farming on such land is very remote. While about half the potassium, nitrogen, and organic matter, and about one-fourth the phosphorus contained in manure will be lost by three or four months’ exposure in the ordinary pile in the barn yard, there 191S ] McDonough County 45 is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while the animals destroy two-thirds of the organic' matter and retain one-fourth of the nitrogen and phosphorus in average live-stock farming, they retain less than one-tenth of the potassium, from the food consumed ; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 67^ inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent cultivation) would permanently maintain the potassium in grain farming by renewal from the subsoil, provided one-third of the potassium is removed by cropping before the soil is carried away. From all of these facts it will be seen that the potassium problem is not one of addition but of liberation; and the Rothamsted records show that for many years other soluble salts have practically the same power as po- tassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other elements, is not known, but where much potassium is removed, as in the entire crops at Rothamsted, with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909, and 1910 on the Fairfield experiment field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium and costing $5.10, in- creased the yield of corn by 9.3 bushels per acre: while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4.00, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit has paid for itself; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield include an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure had been applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bush- els, while the 600 pounds of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was produced by the addition of either potassium sulfate or kainit ; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for, and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant-food elements, es- pecially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown that potassium salts and most other soluble salts increase the solu- bility of the phosphorus in soil and in rock phosphate as determined by chem- ical analysis; also that the addition of glucose with rock phosphate in pot- culture experiments increases the availability of the phosphorus, as measured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the organic matter of the food consumed, it is easy to determine from Table A 46 Soil Report No. 7 [September, that more organic matter will be supplied in a proper grain system than in a strictly live-stock system; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious interference with the capillary movement of the soil moisture, a common danger from plowing un- der too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming, or when both grain and straw are sold, of course the draft on potassium will then be so great that in time it must be renewed by some sort of application. As a rule, such farmers ought to secure manure from town, since they furnish the bulk of the material out of which manure is produced. Calcium- and Magnesium When measured by the actual crop requirements for plant food, mag- nesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses 1 of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of calcium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of magnesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in T905. And practically the same amount of’ calcium was found by analyzing the Rothamsted drainage waters. Common limestone, which is calcium carbonate (CaC 0 3 ), contains, when pure, 40 percent of calcium, so that 800 pounds of limestone are equivalent to 320 pounds of calcium. Where 10 tons per acre of ground limestone were applied at Edgewood, Illinois, the average annual loss during the next ten years amounted to 790 pounds per acre. The definite data from careful investigations seem to be ample to justify the conclusion that where lime- stone is needed at least 2 tons per acre should be applied every 4 or 5 years. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. (See Soil Report No. 1.) Thus limestone has a positive value on some soils for the plant food which it supplies, in addition to its value in correcting soil acidity and in improving the physical condi- tion of the soil. Ordinary limestone (abundant in the southern and western parts of the state) contains nearly 800 pounds of calcium per ton; while a good grade of dolomitic limestone (the more common limestone of northern Illinois) contains about 400 pounds of calcium and 300 pounds of mag- nesium per ton. Both of these elements are furnished in readily available form in ground dolomitic limestone. L Reported by Doctor Bartow and associates, of the Illinois State Water Survey. , Univ«i'!»;ty cf Illinois UNIVERSITY OF ILLINOIS Agricultural Experiment Station URBANA, ILLINOIS, OCTOBER, 1913 SOIL REPORT NO. 8 a. MOSIER, . FISHER State Advisory Committee on Soil Investigations Ralph Allen, Delavan A. N. Abbott, Morrison P. I. Mann, Gilman J. P. Mason, Elgin C. V. Gregory, 538 S. Clark Street, Chicago Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief in Agronomy and Chemistry Soil Survey — J. G. Mosier, Chief A. F. Gustafson, Associate S. V. Holt, Associate H. W. Stewart, Associate H. C. Wheeler, Associate F. A. Fisher, Assistant F. M. W. Wascher, Assistant R. W. Dickenson, Assistant G. E. Gentle, Assistant 0. I. Ellis, Assistant Soil Experiment Fields — 0. S. Fisher, Assistant Chief J. E. Whitchurch, Associate E. E. Hoskins, Associate ^ F. C. Bauer, Associate F. W. Garrett, Assistant H. C. Gilkerson, Assistant H. F. -T. Fahmkopf, Assistant A. F. Heck, Assistant H. J. Snider, Assistant Soil Analysis — J. H. Pettit, Chief Soil Biology — E. Van Alstine, Associate A. L. Whiting, Associate J. P. Aumer, Associate W. R. Schoonover, Assistant W. H. Sachs, Associate Gertrude Niederman, Assistant W. R. Leighty, Assistant L. R. Binding, Assistant Soils Extension — C. B. Clevenger, Assistant C. C. Logan, Associate INTRODUCTORY NOTE About two-thirds of Illinois lies in the corn belt, where most of the prairie lands are black or dark brown in color. In the southern third of the state, the prairie soils are largely of a gray color. This region is better known as the wheat belt, altho wheat is often grown in the com belt and com is also a com- mon crop in the wheat belt. Moultrie county, representing the com belt ; Clay county, which is fairly representative of the wheat belt; and Hardin county, which is taken to repre- sent the unglaciated area of the extreme southern part of the state, were se- lected for the first Illinois Soil Reports by counties. While these three county soil reports were sent to the Station’s entire mailing list within the state, sub- sequent reports are sent only to those on the mailing list who are residents of the county concerned, and to any one else upon request. Each county report is intended to be as nearly complete in itself as it is practicable to make it, and, even at- the expense of some repetition, each will contain a general discussion of important fundamental principles in order to help the farmer and landowner understand the meaning of the soil fer- tility invoice for the lands in which he is interested. In Soil Report No. 1, “Clay County Soils,” this discussion serves in part as an introduction, while in this and other reports, it will be found in the Appendix ; but if necessary it should be read and studied in advance of the report proper. BOND COUNTY SOILS By CYRIL G. HOPKINS, J. G. MOSIER, J. H. PETTIT, and O. S. FISHER Bond county is located nominally in the lower Illinois glaciation, but much of the area, especially the northwestern part, extends over the broad transition zone between the lower and the middle divisions of the Illinois glaciation, and for this reason some of the soil types are rather better than the average soils of the same type in southern Illinois. This zone seems once to have been an extensive morainal region. Altho some moraines still exist as long ridges, most of them have been reduced by erosion to rounded hills, so that only 41/4 percent of the county is now covered by such formation. Other hilly lands, formed largely by stream erosion, oc- cupy more than 16 percent of the area. The topography of the more extensive undulating and level uplands was probably produced very largely by the influence of an ice sheet which once cov- ered this region. Like most of the state, this county was overlain by an ice sheet during what is known as the Glacial period. During that period accumulations of snow and ice in parts of Canada became so great that they pushed southward until a point was reached where the ice melted as rapidly as it advanced. In moving across the country, the ice gathered up all sorts and sizes of stone and earthy materials, including masses of rock, boulders, pebbles, and smaller par- ticles. Some of these materials were carried for hundreds of miles and rubbed against the surface rocks or against each other until ground into powder. When the limit of advance was reached, where the ice largely melted, this material would accumulate in a broad undulating ridge, or moraine. When the ice melted away more rapidly than the glacier advanced, the terminus of the glacier would recede and leave the moraine of glacial drift to mark the outer limit of the ice sheet. The ice made many advances and with each advance and recession a terminal moraine was formed. These moraines are now seen as broad ridges that vary from one to ten miles in width. Thruout the state these advances and recessions of the ice sheet left a system of terminal moraines (irregularly con- centric with Lake Michigan) having generally a steep outer slope while the inner slope is longer and more gradual. (See state map in Bulletin 123.) The material transported by the glacier varied with the character of the rocks over which it passed. Granites, limestones, sandstones, shales, etc., were mixed and ground up together. This mixture of all kinds of boulders, gravel, sand, silt, and clay is called boulder clay, till, glacial drift, or simply drift. The grinding and denuding power of glaciers is enormous. A mass of ice 100 feet thick exerts a pressure of 40 pounds per square inch, and this ice sheet may have been hundreds of feet in thickness. The materials carried and pushed along in this mass of ice, especially the boulders and pebbles, became powerful agents for grinding and wearing away the surface over which the ice passed. 1 2 Soil Report No. 8 [October, Ridges and hills were rubbed down, valleys filled, and surface features changed entirely. As the glacier melted in its final recession, the material carried in the great mass of ice was deposited somewhat uniformly, yet not entirely so, over the intermorainal tracts, leaving extensive areas of level, undulating, or rolling plains. The depth of glacial drift in Bond county varies from a few feet to more than 200 feet, as shown by borings for wells and mines. A thickness of 204 feet was determined by a boring in Greenville. Leverett’s estimate for the average thickness of the drift in the county is 85 feet. The lower Illinois glaciation is characterized by light-colored soils which are usually strongly acid, whereas in the middle and upper Illinois glaciations the darker colored corn-belt soils predominate. Physiography The highest point in Bond county, 650 feet, is in section 30, township 7 north, range 2 west, while the lowest, about 430 feet, is in the Kaskaskia bot- toms in the southeast corner of the county. This gives a difference in altitude of 220 feet. The following are the altitudes in feet above sea level of some sta- tions and towns : Greenville, 555 ; Hookdale, 503 ; Mulberry Grove, 549 ; Perrion, 517 ; Pocahontas, 498 ; Reno, 585 ; Sorento, 591 ; Stubblefield, 510 ; Smithboro, 548 ; Tamalco, 465 ; Baden Baden, 495 ; Old Ripley, 540 ; Pleasant Mound, 515. The entire county lies in the drainage basin of the Kaskaskia or Okaw river, the general slope being from north to south. About three-fourths of the area is drained thru Shoal creek and its tributaries and thence into the Kaskaskia, while about one-fourth of the area along the east side is drained directly into the Kaskaskia by means of small tributaries. (Beaver creek is a tributary of Shoal creek.) The large streams of the county have cut valleys varying from 25 to 125 feet below the upland, the deeper ones being in the northern part of the county. These valleys have permitted considerable erosion by the small tributaries, and as a result the upland adjacent to the larger streams is usually cut up into hills and valleys unsuited to ordinary agriculture. Before the land was put under cultivation, forests had advanced up the streams and were slowly invading the prairies, thus producing a belt of timber soil along the streams. Soil Material and Soil Types The Illinois glacier covered Bond county and left a thick mantle of drift, completely burying the old soil that preceded it. Then a long period elapsed, during which a soil known as the old Sangamon soil was formed on the surface of this drift. Later other ice invasions occurred, but they covered only the northern part of the state. (See state map in Bulletin 123, Iowan and Wis- consin glaciations.) These later ice sheets did not reach Bond county, but finely ground rock (rock flour) in immense quantities was carried south by the waters from the melting ice and deposited on the flooded plains, where, when dry, it was picked up by the wind, carried farther, and finally deposited on the surface, burying the old Sangamon soil 1 to a depth of 5 to 20 feet or more. This wind-blown material, ’The Sangamon soil may sometimes be seen in cuts as a somewhat dark or bluish sticky clay or a weathered zone of yellowish or brownish clay. 1918] Bund County 3 called loess, is a mixture of all kinds of material over which the glacier passed. It may be recognized as a yellow, fine-grained material naturally free from glacial pebbles, usually underlain by the pebble-bearing drift. After the loessal material was deposited over the country, the surface stratum became mixed with more or less organic matter and thus was gradually changed into soil. Surface washing has produced other changes. The soils of Bond county are divided into the four following classes : (1) Upland prairie soils. These were originally covered with wild prairie grasses, the partially decayed roots of which have been the chief source of the or- ganic matter. The flat prairie land, naturally poorly drained, contains the higher amount of organic matter because the grasses and roots grew more luxuriantly there and were largely preserved from decay by the higher moisture content of the soil. (2) Upland timber soils, including those zones along stream courses over which forests once extended. These soils contain less organic matter than the upland prairie soils, because the large roots of dead trees and the surface ac- cumulations of leaves, twigs, and fallen trees were burned by forest fires or suffered almost complete decay. The timber lands may be divided roughly into three classes : the level, the undulating, and the hilly areas. (3) Ridge soils, including those on morainal ridges, most of which have been forested. They may be divided into pervious and tight (almost impervious) . The former class includes some of the best soils of the county, while the soils of the latter class are among the poorest. (4) Bottom-land soils, including the flood plains along streams. Table 1. — Soil Types op Bond County Soil type No. Name of type Area in square miles Area in acres Percent of total area 330 (a) Upland Prairie Soils (page 24) Gray silt loam on tight clay 121.49 77 754 32.66 328 Brown-gray silt loam on tight clay 61.49 39 354 16.54 329 Drab silt loam 2.46 1 574 .66 331 Deep gray silt loam 2.19 1 401 .59 325.1 Black silt loam on clay 2.48 1 587 .67 (b) Upland Timber Soils (page 33) 334 Yellow-gray silt loam 48.76 31 206 13.13 335 Yellow silt loam 60.09 38 458 16.15 332 Light gray silt loam on tight clay 16.45 10 528 4.42 332.1 White silt loam on tight clay .68 435 .18 235 (c) Eidge Soils (page 42) Yellow silt loam 12.41 7 942 3.33 233 Gray-red silt loam on tight clay 1.44 922 .39 245 Yellow fine sandy silt loam 1.98 1 267 .53 1331 (d) Bottom-Land Soils (page 44) Deep gray silt loam 26.22 16 781 7.05 1326 Deep brown silt loam 13.74 8 794 3.70 8 ! ! ! Total 371.88 238 003 100.00 Table 1 shows the area of each type of soil in the county, and its percentage of the total area. The accompanying map shows the location and boundary lines of every type of soil in the county, even down to areas of a few acres ; and in 4 Soil Report No. 8 [October, Table 2 are reported the amounts of organic carbon (the best measure of the or- ganic matter) and the total amounts of the five important elements of plant food contained in 2 million pounds of the surface soil of each type (the plowed soil of an acre about 6% inches deep). In addition, the table shows the amount of limestone present, if any, or the soil acidity as measured by the amount of lime- stone required to neutralize the acidity existing in the soil. 1 THE INVOICE AND INCREASE OF FERTILITY IN BOND COUNTY SOILS Soil Analysis In order to avoid confusion in applying in a practical way the technical information contained in this report, the results are given in the most simplified form. The composition reported for a given soil type is, as a rule, the average of many analyses, which, like most things in nature, show more or less varia- tion; but for all practical purposes the average is most trustworthy and suf- ficient. (See Bulletin 123, which reports the general soil survey of the state, together with many hundred individual analyses of soil samples representing twenty-five of the most important and most extensive soil types in the state.) The chemical analysis of a soil gives the invoice of fertility actually pres-, ent in the soil strata sampled and analyzed, but, as explained in the Appendix, the rate of liberation is governed by many factors. Also, as there stated, prob- ably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that the productive power of normal soil in humid sec- tions depends upon the stock of plant food contained in the soil and upon the rate at which it is liberated. The fact may be repeated, too, that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, while seven are secured from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes) in case the amount liberated from the soil is insufficient. But even the leguminous plants (which include the clovers, peas, beans, alfalfa, and vetches) , in common with other agricultural plants, secure from the soil alone six elements (phosphorus, potassium, magnesium, calcium, iron, and sulfur) and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. 'The figures given in Table 2 (and in the corresponding tables for subsurface and sub- soil) are the averages for all determinations, with some exceptions of limestone or acidity present. Some soil types, particularly those which are subject to erosion, may vary from acid to alkaline, especially in the subsurface or subsoil; and in such cases abnormal results are discarded, a report of the normal conditions being more useful than any average of figures involving both plus and minus quantities. Co// Urj Sg e c t i, Ki/12 H^Z 111 | If " 3 1 I : 1 1 ! sm® l I.t 3 1 % ! II 1 1 I I f § I 1 1 i f I I I I 1 ■ ■■ I u i I I f I 1 aa i | ■ s IL SURVEY MAP OF BOND COUNTY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Bond County 5 Table A in the Appendix shows the requirements of large crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally from natural sources in sufficient abundance, compared with the amounts needed by plants, so that they are never known to limit the yield of common farm crops.) As already stated, the data in Table 2 represent the total amounts of plant- food elements found in 2 million pounds of surface soil in Bond county, which corresponds to an acre about 6% inches deep. This includes at least as much soil as is ordinarily turned with the plow, and represents that part with which the farm manure, limestone, phosphate, or other fertilizer applied in soil improve- ment is incorporated. It is the soil stratum that must be depended upon in large part to furnish the necessary plant food for the production of crops, as will be seen from the information given in the Appendix. Even a rich subsoil has little or no value if it lies beneath a worn-out surface, for the weak, shallow- rooted plants will be unable to reach the supply of plant food in the subsoil. If, however, the fertility of the surface soil is maintained at a high point, then the plants, with a vigorous start from the rich surface soil, can draw upon the sub- surface and subsoil for a greater supply of plant food. By easy computation it will be found that the most common prairie soils of Bond county do not contain in the plowed soil more than enough total nitrogen for the production of maximum crops for twenty-two years; while the upland timber soils contain, as an average, even less nitrogen than the prairie land. With respect to phosphorus, the condition differs only in degree, nearly nine-tenths of the soil area of the county containing no more of that element than would be required for ten crop rotations if such yields were secured as are Table 2. — Fertility in the Soils of Bond County Average pounds per acre in 2 million pounds of surface soil (about 0 to 6% inches) Soil type No. Soil type Total organic carbon Total nitro- gen Total 1 phos- phorus Total potas- sium Total magne- sium Total calcium Lime- j stone present Soil acidity present Upland Prairie Soils 330 Gray silt loam on tight clay 25 620 2 640 770 27 410 4 710 5 200 560 328 Brown-gray silt loam on tight clay 29 490 2 840 670 31 040 4 590 6 210 100 329 Drab silt loam 36 400 3 640 720 29 780 6 320 7 500 120 331 Deep gray silt loam .... 29 460 2 840 680 24 180 3 780 4 040 960 325.1 Black silt loam on clay. 56 540 4 760 1 020 32 540 9 820 15 540 20 Upland Timber Soils 334 Yellow-gray silt loam.. 26 440 2 530 470 35 500, 5 870 5 320 320 335 Yellow silt loam., 22 110 2 068 696 36 024 6 444 5 040 940 332 Light gray silt loam on tight clay 18 780 1 760 740 26 980 4 720 4 110 280 332.1 White silt loam on tight clay 14 860 1 360 660 30 120 4 380 5 400 1 400 Ridge Soils 235 233 245 Yellow silt loam Gray-red silt loam on tight clay Yellow fine sandy silt loam 21 340 35 700 23 120 1 940 3 600 2 650 740 820 720 38 940 25 600 39 040 5 400 7 140 5 700 8 240 6 580 9 850 20 400 30 Bottom-Land Soils 1331 1 Deep gray silt loam . . . . 33 200 3 120 1 640 37 240 9 160 7 380 80 1326 | Deep brown silt loam . . | 23 420 2 100 1 100 34 480 7 080 9 760 20 Soil Report No. 8 [October, suggested in Table A of the Appendix. It will be seen from the same table that in the case of the cereals about three-fourths of the phosphorus taken from the soil is deposited in the grain, while only one-fourth remains in the straw or stalks. On the other hand, the potassium is sufficient for 20 centuries if only the grain is sold, or for 300 years even if the total crops should be removed end nothing returned. The corresponding figures are about 1,200 and 300 years for magnesium, and about 5,000 and 120 years for calcium. Thus, when measured by the actual crop requirements for plant food, potassium is no more limited than magnesium and calcium, and, as explained in the Appendix, with these elements we must also consider the fact that loss by leaching is far greater than by cropping. These general statements relating to the total quantities of plant food in the plowed soil certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the needs of large crop yields for even one or two generations of people. The variation among the different types of soil in Bond county with respect to their content of important plant-food elements is also very marked. Thus, the richest prairie land (black silt loam on clay) contains about twice as much phosphorus and nitrogen as the common upland timber soils; and the bottom lands are still richer in phosphorus. The most significant facts revealed by the investigation of the Bond county soils are the lack of limestone and the low phos- phorus content of the common upland types, which cover nearly 90 percent of the entire county. And yet both of these deficiencies can be overcome at a rela- tively small expense by the application of ground limestone and fine-ground raw rock phosphate ; and, after these are provided, clover can be grown and nitrogen thus secured from the inexhaustible supply in the air. If the clover were then returned to the soil, either directly or in farm manure, the combined effect of limestone, phosphorus, and nitrogenous organic matter, with a good rotation of crops, would in time double or treble the yield of wheat, corn, and other crops, on most farms. Until the supply of decaying organic matter has been made adequate, some temporary benefit may be derived from the use of a soluble salt or a mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phosphorus as well as furnish available potassium and magnesium, and for a few years such use of kainit- may be profitable on lands deficient in. organic matter. The evidence thus far secured, however, indicates that its use is not ab- solutely necessary and that it will not be profitable after adequate provision is made for decaying organic matter, which contains some potassium and liberates additional supplies from the soil. Fortunately, some definite field experiments have already been conducted on some of these most extensive types of soil in the lower Illinois glaciation, as at DuBois in Washington county, at Fairfield in Wayne county, and at Raleigh in Saline county. Before considering in detail the individual soil types, it seems advisable to study some of the results already obtained where definite systems of soil improvement have been tried out on some of these experiment fields in different parts of southern Illinois. Bond County 7 191S] Results of Field Experiments at DuBois In Tables 3 and 4 are recorded some exceedingly valuable and instructive data. These results have been secured by twelve years of actual trial on the most common type of soil in Bond county, gray silt loam on tight clay, which is also a very common type in Washington county, where the DuBois experiment field is located. Table 3. — Crop Yields in Soil Experiments, DuBois Field: Not Tile-drained Gray silt loam on tight clay; lower Illinois glaciation Corn 1902 Oats 1903 Wheat 1904 Clover 1905 Corn 1906 Oats 1907 Wheat 1908 Soy- beans 1909 Corn 1910 Oats 1911 Clover 1912 1 Wheat 1913 Soil o treatment Bushels or tons per acre s applied lOljNone 6.4 9.4 6.3 1 1.25 I 30.3j 18.8 .8 3.5 1 25.81 1 13.1 .46 7.7 102|Lime 6.7 16.2 6.5 1.57 | 35.2 28.8 8.0 6.7 | 26.2 24.1 40 8.7 103 Lime, crop res .... 5.9 18.1 11.0 1.78 38.0 38.1 8.5 7.2 33.6 31.9 (.92) 14.7 104 Lime, phos 13.4 25.9 25.0 2.42' 38.7 43.8 17.8 8.5 17.6 40.9 1.02 21.0 105 Lime, potas 11.6 27.5 16.2 2.22 48.8, 37.2 14.8 9.3 65.6 29.1 .81 16.8 106 Lime, res., phos . . . 9.3 25.0 32.7 2.30 32.3 46.6 19.8 8.2 30.0 35.9 (2.42) 29.7 107 Lime, res., potas. . 6.8 23.8 20.2 2.34 43.6 43.8 16.5 7.8 67.6 29.1 (3.92) 21.0 108 Lime, phos., potas. 12.4 30.0 27.5 2.86 48.9 50.0 20.8 9.5 73.2 35.3 1.34 30.2 109 Lime, res., phos., potas 10.4 29.1 33.3 2.83 46.3 46.6 19.7 7.8 73.2 38.8 (3.00) 30.2 110 Res., phos., potas . . 2.0 25.6 27.3 2.59 39.9 36.9 10.0 6.3 66.8 26.6 (1.67) 10.7 Average Increase: Bushels or Tons per Acre For lime .3 6.8 .2 .32 4.9 10.0 7.2 3.2 .4 11.0 -.06 1.0 For residues -.8 1.9 4.5 .21. 2.8 9.3 .5 .5 7.4 7.8 .52 6.0 For phosphorus 6.7 9.7 18.5 .85 3.5 15.0 9.8 1.8 -8.6 16.8 .62 12.3 For potassium 4.9 11.3 9.7 | .65 13.6 8.4 6.8 2.6 39.4 5.0 .41 8.1 For res., phos. over phos -4.1 -.9 7.7 -.12 -6.4 2.8 2.0 -.3 12.4 -5.0 1.40 8.7 For phos., res. over res 3.4 6.9 21.7 .52 -5.7 8.5 11.3 1.0 -3.6 4.0 1.50 15.0 For potas., res., phos. over res., phos. . . 1.1 4.1 .6 .53 14.0 0.0 -.1 -.4 43.2 2.9 .58 .5 Value of Crops per Acre - in Twelve Years 1 Plot 1 Soil treatment applied 1 Total value of | twelve crops Value of increase 10l|None $58.39 102|Lime 79.33 $20.94 103 Lime, residues 100.88 42.49 104 Lime, phosphorus 131.37 72.98 105 Lime, potassium 133.18 74.79 106 Lime, residues, phosphorus 151.37 92.98 107 Lime, residues, potassium 156.06 97.67 108 Lime, phosphorus, potassium 171.32 112.93 109 Lime, residues, phosphorus, potassium 180.83 122.44 110 Residues, phosphorus, potassium 130.23 71.84 Value of Increase per Acre in Twelve Years Cost of increase For lime $20.94 $10.00? For residues 21.55 ? For phosphorus 52.04 30.00 For residues and phosphorus over phosphorus 20.00 ? For 'phosphorus and residues over residues For potassium, residues, and phosphorus over residues 50.48 30.00 and phosphorus 29.46 30.00 1 Figures in parentheses indicate bushels of seed ; the others, tons of hay. Soil Report No. 8 [October, Has tile drainage been profitable? There arc 120 comparisons which bear on the answer to this question, and the average of all these results summarized in terms of value shows that the tile drainage has paid $5.59 per acre in twelve years, or 47 cents per acre for each year; whereas it would require at least $1.20 an acre a year to pay 6 percent interest on the cost of the tile drainage, the lines of tile being laid five rods apart at a cost of not less than $20 per acre. Table 4. — Crop Yields in Soil Experiments, DuBois Field: Tile-drained Gray silt loam on tight clay; lower Illinois glaciation Corn 1902 Oats 1903 Wheat 1904 Clover 1905 Corn 1906 Oats 1907 Wheat 1908 Soy- beans 1909 Corn 1910 Oats 1911 Clover 1912 1 Wheat 1913 Soil treatment Bushels or tons per acre Ph applied hi None 1.4 ! 17.2 3.3 1.29 32.5 1 13.1 4.3 3.3 27.4 12.2 .40 6.7 112 Lime 3.3 ! 17.2 11.5 1.72 33.6 | 23.8 11.0 6.2 29.0 19.4 .66 16.5 113 Lime, crop res. . . . 2.7 20.6 9.2 1.79 31.7 30.0 14.5 6.7 36.6 27.2 (1.83) 21.5 114 Lime, phos 6^ 27.5 28.3 2.27 29.7 31.9 19.2 7.2 22.2 30.9 .71 22.8 115 Lime, potas 4.9 27.2 14.7 2.16 47.5 46.3 16.2 7.8 64.2 26.6 .85 21.8 116 Lime, res., phos. . . 8.0 33.8 31.2 2.44 30.5 45.9 19.5 8.8 39.4 35.6 (2.50) 37.2 117 Lime, res., potas. . 7.3 27.2 23.3 2.52 48.3 39.1 18.5 10.2 74.6 32.2 (2.75) 28.8 118 Lime, phos., potas. 14.1 25^6 32.2 2.95 55.2 44.4 23.0 10.3 76.4 33.4 1.31 30.8 119 Lime, res., phos., potas 10.4 31.9 30.5 2.89 51.6 42.2 21.3 11.3 75.8 38.8 (2.33) 29.5 120 Res., phos., potas. 4.8 33.1 28.2 2.79 50.7 35.3 12.0 6.7 65.4 28.1 (1.83) 24.0 Average Increase : Bushels or Tons per Acre For lime 1.9 1 .0 8.2 .43 1.1 10.7 6.7 2.9 1.6 | 7.2 .26 9.8 For residues -.6 3.4 -2.3 .07 -1.9 6.2 3.5 .5 7.6 7^8 1.17 5.0 For phosphorus 3.2 10.3 16.8 .55 -3.9 8.1 8.2 1.0 -6.8 11.5 .05 6.3 For potassium 1.6 10.0 3.2 .44 13.9 22.5 5.2 1.6 35.2 7.2 .19 5.2 For res., phos. over phos 1.5 6.3 2.9 .17 .8 14.0 .3 1.6 17.2 4.7 1.79 14.4 For phos., res. over res 5.3 13.2 22.0 .65 -1.2 15.9 5.0 2.1 2.8 8.4 .67 15.7 For potas., res., phos. over res., phos. . . 2.4 -1.9 -.7 .45 21.1 -3.7 1.8 1 2.5 36.4 3.2 -.17 -7.7 Value of Crops per Acre in Twelve Years Plot! Soil treatment applied i Total value of | twelve crops Value of increase 111 112 None $ 57.66 88.97 $ 31.31 113 114 115 Lime, residues 108.25 121.82 133.59 50.59 64.16 75.93 Lime, phosphorus [Lime, potassium 116 117 118 ILime, residues, phosphorus 161.83 166.36 178.08 104.17 108.70 120.42 Lime, residues, potassium iLime, phosphorus, potassium 119 120 [Lime, residues, phosphorus, potassium 181.63 150.62 123.97 92.96 | Residues, phosphorus, potassium Value of Increase per Acre in Twelve Years Cost of increase For For For For For For lime residues $31.31 19.28 33.85 40.01 53.58 19.80 $10.00? ? 30.00 ? 30.00 30.00 phosphorus residues and phosphorus over phosphorus phosphorus and residues over residues potassium, residues, and phosphorus over residues and phosphorus 1 Figures in parentheses indicate bushels of seed ; the others tons of hay. Bond County 9 191S] Is the application of lime and phosphorus of benefit on this type of soil? The answer to this question is found in the fact that the value of the twelve crops on the untreated land amounted to only $58.02, whereas the value of the in- crease produced by lime and phosphorus was $68.58; as an average of the two series. In other words, this treatment has resulted in an increase greater than the crop produced by the unaided land, raising the crop values from $58.02 to $126.60, counting corn at 35 cents a bushel, oats at 30 cents, wheat at 70 cents, hay at $6 a ton, clover seed at $6 a bushel, and soybeans at $1 a bushel— prices that are probably sufficiently below the ten-year average to provide for the ex- pense of application and of harvesting and marketing the increase. It should be stated, too, that the application of lime and phosphorus has produced a marked improvement in the quality of the crops (especially in the wheat and clover), for which credit is not given in these values. The materials used per acre in these experiments were as follows : 5 tons of slaked burned lime (applied only at the beginning of the experiments), 2400 pounds of steamed bone meal (800 pounds for each four-year rotation), and 1200 pounds of potassium sulfate (400 pounds for each rotation). Other investiga- tions (reported in Circulars 110, 127, 157, 165, and 168) have shown that ground natural limestone and fine-ground natural rock phosphate are more economical and profitable forms of lime and phosphorus, and that the same effect produced by potassium sulfate can also be secured at much less expense either by means of decaying organic matter (from crop residues, green-manure crops, or farm ma- nure) , or by the use of less expensive soluble salts, such as kainit, as shown in the Appendix. If ground limestone had been used on the DuBois field, $10 would have paid for the full equivalent of the slaked lime applied, and allowing $30 for the bone meal (its actual cost), we find that the increase produced has paid for the materials and left a net profit of $2.38 per acre per annum, or 70 percent above the cost. As an average of both series, lime alone has paid back $26.12 per acre in twelve years, and phosphorus used in addition to lime and crop residues has paid back $52.03: Furthermore, about one-third of the lime applied and at least two-thirds of the phosphorus applied still remain in the soil for the benefit of future crops. The potassium (kalium) applied during the twelve years has cost $30, and when applied in addition to lime, phosphorus, and crop residues, it has produced increases valued at $24.63, leaving a loss of 45 cents per acre per annum. Further- more, the potassium removed is equal to the total amount applied. On five duplicate plots in the DuBois field commercial nitrogen was used either alone or with other elements during the first three years, but at a large financial loss and with no apparent residual effect. Since 1907, a system has been adopted for these plots which supplies both nitrogen and organic matter by means of crop residues. A study of the detailed results shows an increasing effect from the organic matter thus supplied. The value of the increase pro- duced by the crop residues during the last rotation (four years) was $13.89 per acre where they were used over lime, and $22.79 where they were used over both lime and phosphorus, this representing the average of the two series of plots. The corresponding figures for the gross return from $45 worth of commercial nitro- gen used during the first rotation are $2.16 and $4.21. 10 Soil Report No. 8 [ October , 101 0 $58.39 102 103 104 105 106 107 108 109 110 L LR LP LK LRP LRK LPK LRPK RPK $79.33 $100.88 $131.37 $133.18 $151.37 $156.06 $171.32 $180.83 $130.23 Plate 1. — Crop Values for Twelve Years DuBois Experiment Field; Land Not Tile-drained (L — lime or limestone; R — residues; P —phosphorus; K=potassium, or kalium] 1918 1 Bond County 11 Plate 2. — Crop Values for Twelve Years DuBois Experiment Field; Land Tile-drained (L=lime or limestone; B=residues; P=phosphorus; K=potassium, or kalium) 12 Soil Keport No. 8 [i October , It should be kept in mind that the first clover to be plowed under on the DuBois field was in 1912, the system of supplying nitrogen in crop residues hav- ing been practiced only since 1907, and the clover having failed in 1908 owing to drouth. The small soybean crop of 1909 furnished but little straw, and the other straw and corn stalks are of slow action, so that final conclusions cannot yet be drawn as to the benefit of crop residues when the system is fully under way. Of course these organic residues are provided not only to furnish nitro- gen, but also to aid the liberation of mineral plant food, especially potassium. In this connection a study of the effect of potassium is important. It is an interesting fact that in aggregate value and on the corn crop, po- tassium has produced thus far an even larger benefit than phosphorus. Either one of these elements has paid well when used without the other ; whereas neither has paid its cost when used in addition to the other. The soil type of the DuBois field contains in 2 million pounds of surface soil about 800 pounds of phosphorus and 25,000 pounds of potassium. After limestone and organic matter carrying nitrogen have been supplied, phosphorus is the only addition that is absolutely essential for the maintenance of plant food in permanent rational systems of farming. A summary of the twelve years’ results shows, as an average of the two series, a crop value of $58.02 per acre from the unfertilized land, and increased values as follows: For lime alone $ 26.12 or 45 percent For nitrogen and organic matter over lime 20.41 or 24 percent For phosphorus as a further addition 52.03 or 50 percent For potassium as a final addition 24.63 or 16 percent For total increase over untreated land $123.19 or 212 percent Thus arranged, the field results are in harmony with what might be ex- pected from the chemical composition of the soil. It should be noted that, of the $24.63 credited to potassium, $13.93, or more than half, is due to its very marked effect upon the corn crop of 1910, when the corn on all potassium plots seemed to possess unusual power of resistance against adverse conditions, in- cluding an attack by chinch bugs. The com crop of 1906 also showed benefit from potassium, $6.14. Thus $20.07, or four-fifths of the benefit, was produced in two of the twelve crops. With the inadequate supply of active organic mat- ter thus far provided, potassium applied without phosphorus seems to have in- fluenced the liberation of phosphorus from the soil itself, so that the benefit of this stimulating action, combined with the possible direct benefit of soluble potassium applied for its own sake, has exceeded temporarily the direct benefit of applied phosphorus. It must be plain, however, that no system can be per- manent which does not provide for the application of phosphorus ; and that if one desires to make the most rapid progress in the improvement of such soil, he should use limestone, phosphorus, and kainit, until the supply of organic manures becomes sufficient to render the continued use of kainit unprofitable. From the information given in the Appendix, it will be seen that kainit pro- duces greater benefit than potassium sulfate, and at less expense ; so that, while potassium sulfate in addition to phosphorus has been used with loss on the DuBois field, if kainit were substituted for sulfate it might add to the total profits, at least until the soil could be well filled with active organic matter from crop residues or farm manure. 191S ] Bond County 13 The beneficial effect of soluble potassium where no phosphorus has been added, over a period of twelve years, on the DuBois field, and the fact that sodium, an element which has no value as plant food, produced exactly the same increase as potassium over a period of twice twelve years on Broadbalk field at Rothamsted, only support the following statement quoted on page 208 of Bulle- tin 123, “The Fertility in Illinois Soils”: “In considering the general subject of culture experiments for determin- ing fertilizer needs, emphasis must be laid on the fact that such experiments should never be accepted as the sole guide in determining future agricultural practice. If the culture experiments and the ultimate chemical analysis of the soil agree in the deficiency of any plant-food element, then the information is conclusive and final ; but if these two sources of information disagree, then the culture experiments should be considered as tentative and likely to give way with increasing knowledge and improved methods to the information based on chemical analysis, which is absolute.” 1 Results of Field Experiments at Fairfield The Fairfield experiment field is divided into four tracts of ten acres each, and cultivated in a four-year rotation, consisting of corn, cowpeas or soybeans, wheat, and clover. If the clover fails, cowpeas or soybeans may be substituted for that season ; if the winter wheat fails, oats may be substituted in the spring. One half of the field, or twenty acres, is tile-drained, while the other half has only the ordinary surface drainage as commonly provided by plowing in rather narrow lands and keeping the middle furrows open. On both the tiled and the untiled land grain farming is practiced on one half and live-stock farm- ing on the other half. A part of each of these divisions is treated with two tons of limestone and one ton of fine-ground raw rock phosphate, per acre, every four years, while another part is not so treated. In the system of grain farming, all produce except the grain or seed is re- turned to the land, while in the live-stock farming all produce (or its equivalent) is used for feed and bedding and the manure returned to the land in propor- tion to the crop yields produced during the previous rotation. Thus, if the land treated with manure, limestone, and phosphate produces, as an average in one rotation, one-half larger crops than the land which receives manure alone, then one-half more manure is applied to that land for the following rotation. Likewise, in the grain system, the clover and other crop residues returned are in proportion to the yield produced during the rotation on the respective parts of the field. It should be stated that during the first rotation the manure was applied in the same amount (8 tons per acre) on all fields in the live-stock system. The regular plan is to apply the phosphate and plow it under with manure or other organic matter, and to apply the limestone immediately after the ground is plowed for wheat, in order that the limestone may be mixed with the surface soil in the preparation of the seed-bed where clover is to be seeded the following 'Taken from “Culture Experiments for Determining Fertilizer Needs,” by C. G. H. in Cyclopedia of American Agriculture, Volume I, page 475. 14 Soil Report No. 8 [October, spring. However, the time and method of application are very secondary mat- ters ; the important thing is to get the limestone and phosphate on the land and well mixed with the plowed soil, altho it is better to mix one with the soil before applying the other, because when applied in intimate contact with each other the limestone tends temporarily to lessen the availability of the phosphorus, prob- ably by immediately neutralizing the nitric, carbonic, and organic acids pro- duced in the decay of organic matter. At $1.25 a ton for limestone and $7.50 a ton for rock phosphate, the cost of those materials for four years amounts to $10 an acre. After three or four rotations, however, the phosphate applications will be reduced to about one-half ton, which will reduce the annual expense to about $1.50 per acre. This expense would be practically covered by an increase of 4 bushels of corn, iy 2 bushels of cowpeas or soybeans, 2 bushels of wheat, or 14 ton of hay, at very moderate prices. In Tables 5, 6, 7, and 8 are recorded the crop yields obtained since experi- ments were begun on four different series of plots on the Fairfield field. 1 Only two series were under experiment during the first year (1905), and all the first four years are to be considered as preliminary, in part because of the impossi- bility of securing the ordinary benefits of a four-year rotation during the first rotation period, in part because during the first four years, in the live-stock system, the manure was applied uniformly regardless of crop yields, and, in particular, because the present plan of returning crop residues was not begun until the end of the first four years, whereas the use of manure was begun the Plate 3. — Clover on Fairfield Experiment Field, 1910. (The first crop, shown in pho- tographs, was clipped and left on the land; the second crop produced no clover SEED ON THE UNTREATED LAND, BUT 1% BUSHELS WERE HARVESTED WHERE THE LIMESTONE AND PHOSPHATE WERE APPLIED WITH NO POTASSIUM SALTS) ’Other parts of this experiment field are used for investigations relating to crop produc- tion, such as the testing of varieties. 1913 ] Bond County 15 first year (1905) on Series 100, the second year (1906) on Series 400, the third year (1907) on Series 300, and the fourth year (1908) on Series 200. In the fall and winter of 1905-06 a system of tiling with a good grade and a satisfactory outlet was laid. Four-inch tiles were placed only four rods apart, the two lines on the east half of each series about 20 to 24 inches deep and the two on the west half about 36 to 40 inches deep. Before the ditches were filled, the tile in Series 400 was covered with about 4 inches of gravel, that in Series 300 with 4 inches of cinders, and that in Series 200 with 6 inches of straw. In Series 100 the tile was covered with only the natural dirt. Some of the tiled land of this field is more nearly level than the untiled land, altho the entire field is what would be called level prairie land. As an average of all results reported in Tables 5, 6, 7, and 8, from these four series of plots, the tile drainage has paid $9.11 per acre in eight years, or $1.14 per acre for each year; whereas it would require at least $1.50 an acre a year to pay 6 percent interest on the cost of the tile drainage, which was not less than $25 per acre. It may be added, however, that for the last four years the average increased value resulting from tiling has been $1.80 per acre per year, which would pay a fair rate of interest on the investment if the cost of tiling did not exceed $30 per acre. While it is very possible that, with the continued use of clover (the “best subsoiler”) in the rotation, the tile drainage may ultimately prove to be a profit- able investment, it is plain that the first requisites for the improvement of this soil are limestone, phosphorus, and organic matter. Plate 4. — Clover on Fairfield Experiment Field, 1910. (The first crop, shown in PHOTOGRAPH, MADE % TON OF FOUL GRASS WITH BUT LITTLE CLOVER WHERE MANURE ALONE WAS USED, AND 2% TONS OH CLEAN CLOVER HAY WHERE THE SAME AMOUNT OF MANURE WAS USED WITH LIMESTONE AND PHOSPHATE WITH NO POTASSIUM SALTS) Soil Repoet No. 8 [October, | 3.9 | .4 | 10.2 of seed; the others tons of hay. 101S] Bond County 17 Soil Ueport No. 8 [October, 1918 ] Bond County 19 20 Soil Report No. 8 [October, As a general average of both systems of farming on both the tiled and the untiled land, on all series, the increases produced by limestone and phosphorus during the first rotation were valued at $9.94 1 an acre, or about the cost of these materials delivered at most railroad stations in southern Illinois. The values of the increases in the second rotation averaged $24.19, or nearly two and one-half times the cost of the second application of both limestone and phosphate. These increases should be still further augmented in the third rotation because of the larger amount of organic manures to be returned to the better yielding land and because of the continued positive enrichment of the soil in phosphorus and limestone. During the first four years, the limestone and phosphate, costing $10, pro- duced a gain valued at $7.42 when applied without organic matter, and a gain of $12.46 when applied with farm manure; and during the second four years the increases due to $10 worth of limestone and phosphate were valued at $19.44 when applied with crop residues and $28.93 when applied with farm manure. By referring to the Appendix (page 57), it will be seen that on the Fairfield field potassium salts have produced almost no effect when used in connection with farm manure; whereas the largest effect thus far secured from limestone and phosphate has been obtained where these materials are applied with farm ma- nure. It will be noted, however, that their effect was greater with crop residues during the second rotation than with farm manure during the first. Since the use of crop residues in these experiments was not begun until four years after the first application of manure, no conclusion is justified as to whether the resi- due system or the manure system will ultimately prove best for this soil. The important thing is that the soil can be profitably enriched by either. A cross comparison of the average crop values of the four series of plots shows the value of four crops as $25.41 with the use of farm manure and $24.18 with the use of crop residues, and perhaps this is reasonably trustworthy. Where limestone and Table 9. — Crop Values per Acre, Fairfield Experiment Field First Rotation: Average of Four Series Soil treatment None Farm manure Limestone Phosphate Farm manure Limestone Phosphate Value of four crops $20.84 $25.41 $28.26 $37.87 Second Rotation: Average of Four Series Soil treatment Farm manure Crop residues Limestone Phosphate Farm manure Limestone Phosphate Value of four crops , . . 1 $24.18 $29.51 $43.62 $58.45 'Attention is here called to the fact reported in the Appendix (page 57) that at Fair- field where potassium salts are applied to one half of the land under experiment they produce practically no effect on the manured land, while the effect is very appreciable on the unmanured land. Altho the potassium salts are applied to one half of the check plots the same as to one half of the land receiving limestone and phosphorus, so that the $9.94 is the actual increase produced by the limestone and phosphorus above the return from the land otherwise treated the same, nevertheless there is a possibility that on part of the land represented in this result the effect of the potassium salts was different where used with limestone and phosphorus than where used alone. No potassium salts had been applied to the land where the accompanying photographs were taken. 1913 ] Bond Coonty 21 phosphate are also used, the corresponding values are $37.87 with manure and $43.62 with residues, but this is not a fair comparison because the last value ($43.62) was secured where two applications of limestone and phosphate had been made (see Table 9). In Table 9 are summarized concisely the results of the eight years’ work. When considered in relation to the possible profitable improvement of the most extensive soil type in Bond county, the importance of these figures can scarcely be estimated. It should be remembered, too, that this soil is also the most com- mon type in about twenty counties in southern Illinois. Here we have untreated, well-rotated land producing $20.84 per acre in four years ; while $58.45 is the value at the same prices for the same four crops on land receiving three natural fertilizers — farm manure, ground limestone, and fine-ground raw rock phosphate. If it costs $5 an acre a year to farm the un- 0 M LP MLP R M RLP MLP $20.84 $25.41 $28.26 $37.87 $24.18 $29.51 $43.62 $58.45 First Rotation Second Rotation Plate 5. — Crop Values for Four Years Fairfield Experiment Field (L=lime or limestone; R=residues; P=phosphorus; K=rpotassium, or kalium; N=nitrogen ; M=manure) 22 Soil Report No. 8 [October, treated land, only 21 cents remains to pay the taxes, with nothing for interest ; moreover, the practice of leaving land untreated means a gradual soil depletion, which leads only to future poverty and ruin. If the land would sell at $50 an acre and if money is worth 5 percent, then there is essentially an annual expense of $2.50 an acre for which there is no return ; but if $2.50 per acre per annum is invested in limestone and phosphate in a rational system of farming, it pays back an average of 100 percent during the first rotation, and of 194 to 289 percent dur- ing the second rotation; and this is in addition to the returns from the crop residues and farm manure. Moreover, this is a system of positive soil enrich- ment which leads to the protection of property and to prosperity. The crop residues include the corn stalks, straw from wheat or oats and from soybeans or cowpeas, cover crops, and all clover except the seed. In the live-stock system as many tons of fresh manure are applied to the land as the average number of tons of air-dry produce taken off in crops during the previous rotation — an amount easily produced by using the crops for feed and bedding. The prices used in all these computations are 35 cents a bushel for corn, 30 cents for oats, 70 cents for wheat, $1 for soybeans and cowpeas, $6 for clover seed, and $6 a ton for hay. These prices are stated conservatively in order to avoid any possible exaggeration. If higher prices were used, the computed re- turns from the land and treatment would of course be increased accordingly. In some localities the expense of hauling will be greater than in others ; but it is believed that the prices used provide ample margin for average conditions. The data are reported in detail so that any one can make other computations if de- sired. Results from some other field experiments are recorded in connection with the description of individual soil types. The Subsurface and Subsoil In Tables 10 and 11 are recorded the amounts of plant food in the sub- surface and the subsoil of Bond county. It should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important information contained in these tables is that the common soils of the county are much more strongly acid in the subsurface and the subsoil than in the surface. This emphasizes the importance of having plenty of limestone in the surface to neutralize the acid moisture which rises from the lower strata by capillary action during periods of partial drouth, which are critical periods in the life of such plants as clover. Thus, while the deep brown silt loam bottom- land and the black silt loam on clay of the prairie are practically neutral, the vast areas of the common soils of the county are greatly in need of limestone; and, as already explained, the extensive upland soils are markedly in need of phosphorus and nitrogen. 191S ] Bond County 23 Table 10. — Fertility in the Soils op Bond County Average pounds per acre in 4 million pounds of subsurface soil (about 6% to 20 inches) Soil type No. Soil type Total organic carbon Total nitro- gen Total phos- phorus Total potas- sium Total magne- sium Total cal- | cium Lime- stone present Soil acidity present Upland Prairie Soils 330 Gray silt loam on tight clay 26 100 2 990 1 530 57 540 10 970 9 500 ~3~m 328 Brown-gray silt loam on tight clay 26 460 2 700 1 740 63 820 10 160 10 400 300 329 Drab silt loam 43 400 4 160 2 040 61 560 12 120 15 800 280 331 Deep gray silt loam 27 720 3 200 1 080 53 800 7 800 9 600 5 600 325.1 Black silt loam on clay 91 680 7 320 1 880 63 120 20 600 31 160 40 Upland Timber Soils 334 Yellow -gray silt loam 21 240 | 2 600 1 340 75 500 14 620 8 520 5 200 335 Yellow silt loam 16 980 2 120 1 270 73 820 15 400 8 570 4 080 332 Light gray silt loam on tight clay 11 560 1 400 1 260 60 160 14 260 7 320 10 020 332.] White silt loam on tight clay 7 960| 1 000 1 480 61 400 11 560 10 080 960 Kidge Soils | Yellow silt loam 15 520 2 080 1 000 82 400 12 960 13 840 Grey -red silt loam on tight clay 44 960 4 800 1 440 54 000 24 240 12 760 Yellow fine sandy silt loam 18 520 2 340 1 620 79 900 18 280 11 100 Bottom-Land Soils 1331 Deep gray silt loam : 23 480 2 720 2 200 74 000 16 080110 280 1 4 320 1326 Deep brown silt loam 1 30 200 • 2 880 1 800 69 040 14 120 114 600, I 160 Table 11. — Fertility in the Soils op Bond County Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil 1 Total i Total 1 Total 1 Total 1 Total Total Lime- Soil type Soil type organic nitro- phos- potas- magne- cal- stone acidity No. | carbon gen |phorus| sium | sium cium present present Upland Prairie Soils 330 Gray silt loam on tight 1 clay 27 900 3 340 2 850 88 940 36 180 21 210 2 050 328 Brown-gray silt loam on tight clay 19 650 2 760 2 520 97 290 35 730 31 830 often 329 Drab silt loam 3 720 3 180 89 580 27 300 22 860 540 331 Deep gray silt loam 37 920 3 720 2 280 79 560 31 620 15 600 18 300 325.1 Black silt loam on clay. . . 34 920 3 060 2 760 94 260 37 620 39 840 120 Upland Timber Soils 334 Yellow-gray silt loam 16 260 2 190 2 580 118 140 31 470 18 030 1 12 540 335 Yellow silt loam 12 790 2 170 2 090 105 290 32 240 12 910 15 070 332 Light gray silt loam on tight clay 15 840 2 070 2 670 96 480 30 090 11 460 21 720 332.1 White silt loam on tight clay 10 560 1 860 2 820 96 540 38 700 18 000 25 380 Ridge Soils 235 Yellow silt loam 14 220 2 280 2 520 121 260 35 700 21 060 2 340 233 Grey-red silt 16am on tight clay 20 220 2 040 1 980 114 600 48 120, 38 040 often 245 Yellow fine sandy silt loam 21 060 2 760 2 960 116 040 37 260 24 780 2 010 Bottom-Land Soils 1331 Deep gray silt loam .... J 12 060 1 2 040 3 060 108 240 26 520| 11 880 20 100 1326 Deep brown silt loam.... 1 21 540 1 2 520 2 580 1 106 140 1 15 840 19 380 420 24 Soil Report No. 8 [October, INDIVIDUAL SOIL TYPES (a) Upland Prairie Soils The upland prairie soils of Bond county occupy 190 square miles, or 51 percent of the entire area of the county. Because of their larger content of organic matter, they are usually darker in color than the upland timber soils of similar topography. The accumulation of organic matter in the prairie soils is due to the growth of prairie grasses that once covered them, and whose network of roots has been protected from complete decay by imperfect aeration resulting from the covering of fine soil material and the moisture it contains. The tops of these prairie grasses contributed little organic matter, as they were usually burned by prairie fires or soon became almost completely decayed from exposure to the air. Be- cause of its great age and the loss of mineral plant food by leaching, the most common prairie soil of the lower Illinois glaciation has finally become incapable of supporting such a rank vegetation as the more recently formed and more fertile prairies of the corn belt in central and northern Illinois. Consequently, the southern Illinois prairies are not so rich in organic matter and nitrogen as the corresponding corn-belt soils; indeed, they differ but little from the best timber soil. Gray Silt Loam on Tight Clay (330) Gray silt loam on tight clay is the predominating soil type in the lower Illinois glaciation. It covers 121.49 square miles (77,754 acres), or 32.66 percent of the area of the county. In topography it is nearly level or gently undulating, tho somewhat rolling in places. The type varies primarily in: (1) the organic-matter content; (2) the topography and consequent surface drainage; and (3) the thickness, depth, and density of the tight clay layer underlying it. Where adjoining the somewhat rolling areas of this or other types, or in the vicinity of ridges, this type has received some wash, which has buried the tight clay layer to such a depth that it is less objectionable, and in such places the soil is better than the average soil of this type. On the other hand, where erosion has been somewhat active, the tight layer is near the surface, making a very unproductive soil. This type contains many small areas known as “scalds” or “scald spots,” readily recognized in the plowed field by their light color. On these spots the ordinary surface soil, and in many cases the subsurface soil, is partly or entirely absent, leaving the subsoil on or very near the surface. Ordinarily these spots constitute only a few square rods; occasionally, tho very rarely, one is found covering an acre or more. These “scalds” are very irregular in their occur- rence, some fields being almost free from them while others contain many. Bracted plantain ( Plantago aristata) of stunted growth is a common plant on these “scalds.” The surface stratum, 0 to 6% inches, is a friable silt loam, varying in color from a light to a dark gray and containing sufficient clay to make it slightly plastic when wet. A few small gravels of quartz and concretions of hydrated iron oxid are sometimes found in it. The organic-matter content varies from 1.9 to 2.6 percent ; in other words, from 19 to 26 tons per acre, or an average of 22 tons. The surface soil is fairly pervious to water, but the low organic-matter 1913] Bond County 25 content, and the consequent lack of granulation, renders it in poor tilth, causing it to “run together” readily with heavy rains or with freezing and thawing when very wet. The chief variation in the surface stratum is due to the varia- tion in the organic-matter content. Analysis shows from 10 to 13 percent of the various grades of sand and from 70 to 80 percent of silt. The subsurface stratum varies greatly in thickness. In many of the “scalds” it is entirely absent, while in other places the depth to the subsoil is two feet or more. The average thickness is about 13 inches. It contains 1.1 percent of organic matter, and consists of a silt loam varying in color from gray to almost white. The upper part of the stratum is sometimes about the same color as the surface soil, but ordinarily the plow-line marks the beginning of a much lighter colored soil, which becomes still lighter with depth and passes into a distinct light gray layer deficient in organic matter, close-grained, very com- pact when dry, and very slowly pervious to water. When saturated, it is soft, and posts may be driven thru it readily. A few small quartz gravels and some concretions of hydrated iron oxid are sometimes present. The natural subsoil lies at an average depth of about 20 inches from the surface, but the distance varies from only a few inches on the “scalds” to two feet or more on the best phase of the type. It is usually made up of two distinct layers. The upper layer, extending from the subsurface to an average depth of 30 to 36 inches, consists of tight clay, sometimes erroneously called ‘ ‘ hard-pan, ’ ’ while the lower subsoil is friable, porous, and silty. The tight clay stratum varies from 4 to 12 inches in thickness and is usually a close, silty clay, reddish or yellowish in color, very sticky and gummy when wet, and very hard when dry. Water percolates thru it very slowly. Because of the level topography and the tight clay subsoil, the drainage of this type is, as a rule, rather poor. It is still a question whether the type can be tile-drained profitably; experiments are now in progress with the view of answering this question. The soil is strongly acid and low in nitrogen content. It is in poor physical condition; it “runs together” badly during rains, is too compact for good aera- tion, and is very -unfavorable for moisture movement. Therefore in the manage- ment of this type the chief essentials are the application of limestone and the increase of organic-matter content by every practical means. Limestone is needed, not only to correct soil acidity, but to supply calcium as plant food as well. It also increases granulation, or flocculation, and thus improves the tilth. About two tons per acre of ground limestone should be ap- plied every four or five years, and the initial application may well be from four to six tons. In order to increase the organic-matter content, all forms of vegetation, such as weeds, manure, straw, corn stalks, etc., should be plowed under and no part of them burned. Legume crops, such as cowpeas, soybeans, and red, alsike, or sweet clover, should be grown and turned back into the soil, or fed and the ma- nure returned. Probably no crop will prove better adapted to adding organic matter and nitrogen to the soil than the common sweet clover ( Melilotus alba), a deep-rooting plant which will also help to loosen the tight subsoil and make it more pervious. In order to grow this clover, the soil must be sweetened with ground limestone and well inoculated with nitrogen-fixing bacteria. 26 Soil Report No. 8 [October, This type is also markedly deficient in phosphorus, especially for the grow- ing of such crops as wheat and clover; hence in permanent systems of improve- ment a liberal use of phosphorus is essential. This is applied most economically in the form of fine-ground natural rock phosphate, which should be plowed un- der in intimate contact with farm manure, clover, or cowpeas. If one-half ton per acre is applied every four or five years, the phosphorus content of the soil will be maintained or slowly increased, but an application of one or two tons at one time gives still better results. With the increase in organic matter, the phosphorus content of the plowed soil should be raised finally to at least 2,000 pounds per acre, which will require altogether about five tons of rock phosphate. This system of permanent soil improvement can be hastened, and sometimes with profit during the early years, by applying about 600 pounds of kainit per acre to be plowed under with the initial application of rock phosphate. The action of kainit is explained in the Appendix (see page 57). If used at all it should be with the understanding that it serves in part, at least, as a soil stimu- lant ; and that when plenty of decaying organic matter is provided, the use of kainit may not be profitable. The benefit derived from ground limestone, where a heavy application is made, seems to include some of the effect of soluble salts and to make the use of kainit less important. For results of field experiments on this soil type, see Tables 3 to 9. Brown-Gray Silt Loam on Tight Clay (328) Brown-gray silt loam on tight clay covers 61.49 square miles (39,354 acres), or 16.54 percent of the entire county. The principal area is located between the east and the west branches of Shoal creek. Other large areas are found near Smithboro and east of' Stubblefield. With few exceptions the topography is flat or only slightly undulating. This type contains many “scalds” where the subsoil comes to the surface or injuriously near it, usually less than ten inches. These “scalds” are very ir- regular in their occurrence, some fields being devoid of them, while others con- tain many. They are indicated by their lighter color, distinctly seen when the ground is plowed. The surface soil, 0 to 6% inches, is a dark gray to a brown mealy silt loam, varying in color with its gradation toward other types. It contains about 2.4 percent of organic matter, or 24 tons per acre. The amount varies from 2.1 to 3 percent, or from 21 to 30 tons per acre. The mineral part of the soil is com- posed of 80 to 85 percent of the different grades of silt with 10 to 12 percent of sand, and some clay. Coarse silt seems to be the most abundant constituent. The soil is porous, friable, and easy to work. The subsurface stratum varies greatly in thickness and color. Its average thickness is from 10 to 12 inches, altho it is entirely absent in some places, such as “scalds,” and 18 inches thick in others. It consists chiefly of a grayish brown silt loam, the color becoming lighter with depth. Usually there is a distinct gray or grayish brown layer from 2 to 10 inches thick just above the subsoil. Where the type grades into gray silt loam on tight clay (330), this gray layer in some places becomes quite well developed. On the other hand, where the type grades toward brown silt loam this layer becomes quite indistinct. 19 IS ] Bond County 27 The subsoil is found at variable depths, from only a very few inches from the surface on the “scalds” to 20 inches or more on the better phases. It con- sists of two distinct layers. The upper stratum, from 5 to 16 inches thick, is a plastic, gummy, yellow, drab or dark olive-colored clay, very tight and nearly impervious to water. Below it is a clayey silt, friable and pervious, of a yellow color, or yellow with drab mottlings. The upper layer of the subsoil is too nearly impervious to allow good drain- age, so that special surface drainage in the form of dead furrows must be provided. Probably the lower, flatter land of this type should be tile-drained, the lines of tile being placed not over five rods apart. This opinion is based merely upon observation and reported experience, as no definite experiments in tile drainage have been conducted on this type. In the improvement of this type practically the same methods should be employed as for the gray silt loam on tight clay (330). All crop residues and legume crops not fed on the farm should be turned back into the soil in order to provide nitrogen, liberate mineral plant food, and aid in the physical im- provement of the soil. Deep-rooting crops should be grown in order to loosen up the subsoil and provide more rapid percolation of water and air. This type contains no limestone, and is usually somewhat acid. However, it is not so sour as the gray silt loam on tight clay, and this fact, together with the higher content of calcium and organic matter and some ability to grow clover in favorable seasons, has made it a more productive soil, generally, than the gray prairie. It has been much used for wheat, and possibly because of the many crops removed, this type in Bond county is, as an average, more deficient in phosphorus than the more extensive gray silt loam on tight clay. Where it has long been cropped it is also very poor in active organic matter, so that nitro- gen is one of the important factors which now limit the yield of grain crops. In Table 12 are given the data secured from twelve years’ field investiga- tions on brown-gray silt loam on tight clay, on the soil experiment field near Mascoutah, St. Clair county, which almost corners Bond county on the south- west. These data are from a part of the Mascoutah field where commercial nitrogen, phosphorus, and potassium have all been used in readily available form in order to secure information as quickly as possible. The regular applica- tions per acre have been 100 pounds of nitrogen in 700 pounds of dried blood every year, and 800 pounds of steamed bone meal and 400 of potassium sulfate every four years, corresponding to 25 pounds of phosphorus and 42 of potassium for each year of the rotation. At the time these experiments were begun the claim was commonly made, especially by lime manufacturers, that small amounts of slaked lime should be applied frequently to soils. (The product was sold under the name bf “hydrated” lime at $6 to $10 per ton.) On the Mascoutah field this material was tried, 400 pounds per acre in 1902 and 700 pounds in 1903. No further applications were made until 1909, when the use of ground limestone was be- gun. At that time 1 y z tons per acre was applied, and four years later 2 tons per acre was applied. The first distinct indication of benefit from lime alone appeared in 1913. Nitrogen is clearly the element of greatest benefit on the Mascoutah field, as shown by the fact that the dried blood has increased the crop values, in twelve 28 Soil Report No. 8 f October , years, from $91.05 to $135.50, a gain of $44.45. In comparison, phosphorus has produced an increase valued at $16.60, and potassium an increase valued at only $10.63, when used singly. All other results harmonize well with these val- ues, except those from Plot 507, which indicate a very marked influence from potassium. In fact, the crop values from this plot, which has received lime, nitro- gen, and potassium, are $15.17 higher than those from Plot 509, which has re- ceived lime, nitrogen, phosphorus, and potassium. However, nearly $13 of this Table 12. — Crop Yields in Soil Experiments, Mascoutah Field Brown-gray silt loam on tight clay; middle Illinois glaciation Corn|Corn| 1902 j 1903 Oats 1904 Wheat 1905 i 'orn 1906 Corn 1907 Oats 1908 Wheat 1909 Corn 1910 Corn 1911 Oats 1912 1 1 Wheat 1913 Soil o treatment Bushels per acre PM 1 applied 501 None 32 5 1 43.4 17.5 1 31.7 1 29.1 1 8.8' | 20.7 8.8 11.6 1 9.8 502; jLime | 32.0 1 38.9 22.5 7.8 1 30.8 31.9 6.6 | 17.5 | 8.8 | 11.2 [ 15.5 503 Lime, nitro 1 24.2 47.1 40.0 16.7 53.1 45.8 12.2 20.8 12.4 19.81 32.5 504 Lime, phos 34.4 39.3 68.7 15.0 21.6 24.8 9.1 20.2 6.8 14.6 14.5 505 Lime, potas . 37.5 47.8 25.6 15.7 22.3 32.5 10.6 18.0 10.4 17.0 1 1 12.3 506|Lime, nitro., phos. 1 46.1 69.9 44.11 25.3 56.7 58.8 28.8 32.7 32.4 39.2 33.5 507 Lime, nitro., potas . 59.6 77.4 43.1 1 30.2 59.6 70.0 37.2 30.7 32.0 48.8 27.0 508 Lime, phos., potas. | 53.9 49.0 33.1 j 20.0 19.6 38.1 12.2 22.3 15.2 19.6 18.8 509 Lime, nitro., phos., 1 1 1 potas 47.8 70.5 37.8 28.3 49.6 70.0 30.3 33.7 34.4 37.4 28.3 510 Nitro., phos., potas. j 47.7 52.6 35.9 26.3 42.9 65.3 32.2 33.7 34.8 28.6 30.5 Average Increase: Bushels per Acre For nitrogen -7.8 8.2 17.5 8.9 22.3 13.9 5.6 3.3 3.6 8.6 17.0 For phosphorus 2.4 .4 46.2 7.2 -9.2 -7.1 2.5 2.7 -2.0 3.4 -1.0 For potassium 5.5 8.9 3.i 7.9 -8.5 .6 4.0 .5 1.6 5.8 -3.2 For nitro., phos. over phos 11.7 30.6 -24.6 10.3 35.1 34.0 19.7 12.5 25.6 24.6 19.0 For phos., nitro. over nitro 21.9 22.8 4.1 8.6 3.6 13.0 16.6 11.9 20.0 19.4 1.0 For potas., nitro., phos. over nitro., phos. . 1.7 .6 -6.3 3.0 -7.1 11.2 1.5 1.0 2.0 -1.8 -5.2 Value of Crops per Acre in Twelve Years Plot 1 Soil treatment applied Total” value of twelve crops j Value of increase 501 502 None $ 90.60 91.05 $ .45 503 504 505 Lime, nitrogen . 135.50 107.65 101.68 44.90 17.05 11.08 Lime, phosphorus Lime, potassium 506 507 508 Lime, nitrogen, phosphorus Lime, nitrogen, potassium |Lime, phosphorus, potassium 192.01 207.21 | 124.75 101.41 116.61 34.15 509 510 Lime, nitrogen, phosphorus, potassium Nitrogen, phosphorus, potassium 192.04 178.95 101.44. 88.35 Value of Increase per Acre in Twelve Years Cost of | increase For For For For For nitrogen $44.45 16.60 84.36 56.51 .03 $180.00 30.00 180.00 30.00 30.00 phosphorus nitrogen and phosphorus over phosphorus phosphorus and nitrogen over nitrogen potassium, nitrogen, and phosphorus over nitrogen and phosphorus The oat crop failed in 1912. Bond County 29 1918 j difference is found in the first five crops, which suggests the possible influence of some unknown factor in Plot 507, such as the presence of an old stack bottom. But even if this abnormal effect during those years is disregarded, the data still show a slightly greater benefit from nitrogen and potassium (507) than from nitrogen and phosphorus (506), altho in 1913 a marked superiority of phosphorus appears in this comparison. Here again on this highest yielding plot (507) we meet what seems to be the stimulating influence of the soluble potassium salt. If, however, the treat- ment used on this plot were practiced, it would lead ultimately only to failure and land ruin, for it makes no provision for the restoration or the maintenance of phosphorus, which is unquestionably the most deficient of the five most im- portant elements of plant food. The only guide toward a safe practice for permanent systems of improvement is the chemical composition of the soil. In the lower part of Table 12 is shown the influence of each element in a rational order of application. From the composition of the soil it is clear that both nitrogen and phosphorus must be supplied for permanent systems of farm- ing, altho there may be some question as to which of these two is most needed, because of imperfect knowledge of the condition of the organic matter and of the rate of decomposition under unknown future weather conditions. It must be plain, however, that if potassium is to be used for its own sake, it should pay a profit when applied in addition to both nitrogen and phosphorus. In considering these three elements, nitrogen, phosphorus, and potassium, we find that, starting with $91.05 (the value of the crops for twelve years when lime alone was used), the increases per acre in crop values have been as follows: For nitrogen over lime $ 44.45 For phosphorus as a further addition 56.51 For potassium as a final addition ' .03 For total increase $100.99 This demonstration of more than doubling crop values is highly important, for it shows the possibilities of soil treatment; but of still more importance is the development of methods of producing the same results with profit to the producer. Applied nitrogen has produced exceedingly marked gains, but never enough to pay its cost in commercial form ; and while phosphorus has paid nearly 200 percent on the investment in steamed bone meal when used in addition to nitrogen, the profit is more than offset by the nitrogen deficit. On another part of the Mascoutah field, investigations are in progress where nitrogen is secured by the slower but less expensive practice of growing legumes in the crop rotation and returning to the soil the crop residues or farm manure. In Table 13 are shown for direct comparison the results secured where commercial nitrogen is used and those where these rational means of securing nitrogen are employed, both on lime-phosphorus plots and on plots where lime, phosphorus, and potassium are applied. The records are taken from the legume rotation of the same crops as were grown in identical years in the experiments reported in Table 12. It will be seen that the rotations differ only by the substi- tution of a legume crop for one corn crop. The final averages, including duplicate experiments (except for the potassium), may be considered trustworthy, within Soil Report No. 8 [October, 30 rather narrow limits. The data of the first four years are averaged separately because during those years the residue and manure systems were not well under way. Table 13. — Crop Yields in Soil Experiments. Mascoutah Field Rotation system Corn, corn, oats, and wheat Corn, oats, wheat, and clover Corn, oats, wheat, and clover Soil treatment Lime Nitro. Phos. Lime Nitro. Phos. Potas. Lime Residues Phos. Lime Residues Phos. Potas. Lime Manure Phos. Lime Manure Phos. Potas. 1902 Corn, bu 46.1 47.8 39.6 45.3 42.7 47.1 1903 Corn, bu 69.9 70.5 50.8 56.8 43.1 58.9 1904 Oats, bu 44.1 37.8 36.9 33.4 32.8 39.4 1905 Wheat, bu 25.3 28.3 25.9 28.2 26.3 31.2 Value of four crops . . . $71.54 $72.55 | $60.84 $65.49 $58.28 $70.76 1906!Corn, bu 56.7 49.6 57.1 57.3 54.1 49.1 1907 Corn, bu 58.8 70.0 70.0 84.3 73.0 93.0 1908 i Oats, bu 28.8 30.3 9.7 11.3 10.6 13.1 1909 Wheat, bu 32.7 33.7 32.0 32.7 32.7 33.2 1910 Corn, bu 32.4 34.4 28.6 36.0 27.2 35.2 1911 Corn, bu 39.2 37.4 38.2 29.4 29.6 32.8 1912 1913 Oats, failed Wheat, bu 33.5 28.3 33.5 34.7 32.3 30.2 Value of eight crops. . . . $120.47 | $119.48 $116.63 $123.02 $113.05 $121.84 Av. value of eight crops . $119.97 $119.82 $117.44 Where commercial nitrogen has been used, the crop values for the last eight years average $119.97, with a total cost for nitrogen of $120.00 ; but where crop residues have been used as a source of nitrogen, the average crop value is $119.82, or within 15 cents of that produced with commercial nitrogen. Nearly the same results have been secured where the nitrogen is supplied in farm manure in quan- tities easily produced from the crops grown on the land. These data show that altho practically the same aggregate gross values are secured with “home-grown” nitrogen as with the purchased product, the secur- ing of these values requires that the crop of clover seed in the grain system or the clover hay in the live-stock farming shall bring as large a return as the corn crop which it replaces. Even if no value is assigned to the clover crop, the cost of the nitrogen secured by these rational methods is only about one- fourth its cost in commercial form. Drab Silt Loam (329) Some of the low and more poorly surface-drained areas of the prairie land have received deposits of finer material washed in from the slightly higher sur- rounding land, and in these places a greater amount of organic matter has accumulated, more particularly in the surface and the subsurface strata, owing to the more luxuriant growth of vegetation and the better conditions for pre- venting complete decay. This finer material and the greater accumulation of organic matter have given rise to a type of soil, the drab silt loam (329), which is darker in color, better in texture, and somewhat more productive than the surrounding gray silt loam on tight clay (330), the ordinary prairie land of this glaciation. Drab silt loam in Bond county covers an area of 2.46 square miles (1,574 acres), or .66 percent of the county. 1913 ] Bond County 31 The surface soil, 0 to 6% inches, is a drab to a dark gray. Altho silts form the chief constituent, this stratum always contains some fine sand and, in the poorly drained areas, enough clay to give it some tenacity. The organic matter averages 3.1 percent, or 31 tons per acre. The subsurface stratum varies from a brownish gray to a light drab, fre- quently with blotches of iron oxid. The amount of clay varies considerably, the stratum in some areas being very silty, while in others it has sufficient clay to make it plastic; in either case it is pervious to water. The subsoil, 20 to 40 inches beneath the surface, is a drab to yellowish gray silt or clayey silt. In many areas the subsoil is quite heavy, yet sufficiently pervious so that tile drains should work well. This type needs underdrainage to bring it to its best condition of tilth and productiveness. The physical composition, texture, and structure indicate that tile drainage would be of great benefit, but actual field experiments are neces- sary to determine how satisfactorily tile will work. Besides thoro drainage, one of the most important points in the manage- ment of this type is the maintaining or even the increasing of the organic matter in order to provide sufficient nitrogen to meet the needs of large crops of corn and other non-legumes to be grown in the crop rotation. This can best be done by practicing a rotation of crops in which a legume is used as often as practical and by turning back into the soil all crop residues. If these crops are fed on the farm, the manure should be put back with as little waste as possible. This type in Bond county is very deficient in phosphorus and contains no limestone, altho it is not markedly acid ; hence both phosphate and limestone should be used. Deep Gray Silt Loam (331) Deep gray silt loam occupies low areas in the southeastern part of Bond county where silt has been carried in from the higher lands to such a depth that all evidence of a clay subsoil has been buried to a depth of more than 40 inches. It covers 2.19 square miles (1,401 acres), or .59 percent of the county. The surface soil, 0 to 6% inches, is a gray to dark gray silt loam, changing in shade as it grades into other types. It contains 2.4 percent of organic matter, or 24 tons per acre. The subsurface is a silt loam, lighter in color than the surface, and con- taining 1.2 percent of organic matter. The subsoil is a gray to drab silt, differing from the subsurface in that it contains less organic matter and has layers of clay or clayey silt developed locally. The low organic-matter content of this type indicates the necessity of maintaining or increasing the supply by every practical means. Owing to the character of the subsoil, crops growing on this type have a decided ad- vantage over those on gray silt loam on tight clay (330), provided the subsoil is thoroly drained. The greater porosity and deeper feeding range are of no avail when water is present in excess. Among the prairie soils of Bond county, this type is the most acid and the most deficient in calcium and magnesium; it is also very poor in phosphorus. Phosphate should be applied liberally in connection with organic matter; dolomitic limestone (such as can be secured from Grafton and from most 32 Boil Report No. 8 [October, northern Illinois deposits) will probably give even better results than the more common limestone. Black Silt Loam on Clay (325.1) Black silt loam on clay represents low prairie land that was originally swampy. In position, this type corresponds to the black clay loam in the middle and upper Illinois and early Wisconsin glaciations. In Bond county it covers 2.48 square miles (1,587 acres), or .67 percent of the county. The areas are widely scattered; one of the largest is found south of Old Ripley and two others of considerable size east of Greenville. The surface soil, 0 to 6% inches, is a heavy black silt loam varying in some places to a clay loam. It contains 4.9 percent of organic matter, or 49 tons per acre, an amount sufficient to make it quite granular and keep it in good physical condition if properly drained. The subsurface extends 15 to 18 inches below the surface soil and is a dark clayey silt loam containing about 4 percent of organic matter. The subsoil consists of a clay, varying in color from dark to light drab. The presence of clay and organic matter imparts to this type of soil the property of shrinkage to a very marked degree, and in times of drouth large cracks a foot or more in depth are formed, which sever the roots and damage the crop to some extent. Drainage and good cultivation prevent this to a con- siderable degree. After drainage, rotation of crops and turning under crop residues such as corn stalks, straw, etc., together with good tillage, is all that is necessary to keep the soil in good physical condition. This black silt loam is by far the richest prairie soil in the county, not only in phosphorus and nitrogen, but also in calcium and magnesium; it is somewhat the richest, too, in potassium. The ratio of nitrogen to carbon is 1 to 12, which indicates that the organic matter is more active as well as more abundant in this type than in the other prairie types in Bond county, in which the ratio is only 1 to 10. (Read “Supply and Liberation of Plant Food” in the Appendix.) A liberal use of phosphorus with clover in rotation is needed for marked improvement in crop yields on such soil. No field experiments have been conducted on black silt loam on clay, but its composition is practically the same as the most extensive soil type in the com belt, the common brown silt loam. When well drained and well farmed with a good crop rotation including clover, phosphorus is the single factor which holds the crop yields far below what they would otherwise be. Thus, on the brown silt loam at the Bloomington soil experiment field, the values per acre of eleven crops (1902-1912) on four different plots where no phosphorus was applied were $165.52 (with lime), $173.17 (with lime, crop residues’), $169.66 (with lime, potassium), and $170.57 (with lime, residues, 1 potassium) ; whereas the corresponding values on four other adjoining or intervening plots whose treatment differed only by the addition of phosphorus were $255.44, $251.43, $256.92, and $254.76. Other essentials are so much better provided than phosphorus that the addition of this element paid 300 percent on the in- vestment. J No values are assigned to crop residues plowed under until they reappear in increased yields of subsequent crops. 191S] Bond County 33 (b) Upland Timber Soils The upland timber soils of Bond county aggregate 126 square miles, or more than one-third of the area. They are usually lighter in color than the prairie soils, because of the more nearly complete decay of the residues of timber vegetation. In upland forests these residues consist of fallen leaves, branches, and dead trees, which become almost completely decomposed thru exposure to the oxygen of the air and to fungi. Even the large roots of trees thru exposure at the stump decay rapidly in the surface soil. Occasional forest fires help to complete the destruction. (As already explained, the most common prairie soil of the lower Illinois glaciation, because of its great age and the loss of mineral plant food by leaching, has been reduced in organic-matter content to about the condition of the undulating timber land.) Yellow-Gray Silt Loam (334) Yellow-gray silt loam in Bond county covers 48.76 square miles (31,206 acres), or 13.13 percent of the area of the county. It is found along the streams and generally lies between the eroded zone of yellow silt loam (335) and the prairie types. In topography it is usually undulating, but it varies from nearly level to quite rolling. The normal slopes are long and gentle, but in places very short, abrupt slopes of yellow silt loam occur, which, are .too small in area to be shown separately on the map. The surface drainage is generally good. Erosion takes place on many slopes where no means are taken to prevent it. While this type was once gen- erally timbered, it is also sometimes found extending into the prairie along natural drainage channels, and as these particular areas represent recent erosion of the prairie, “scalds,” or tight-clay outcrops, are often found, the presence of which renders these narrow areas very inferior to the type as a whole, and in some places, almost worthless. These “scald” areas are rarely over two or three acres in extent and more frequently are only a fraction of an acre, often occurring as narrow strips along the streams or draws. The surface soil, 0 to 6% inches, is a yellow to grayish yellow silt loam. The freshly plowed surface when first dry after a rain takes on a decidedly grayish appearance. The type varies to a lighter color as it grades into light gray silt loam on tight clay (332), to a darker color as it grades into the prairie types (330 and 328), and to a more yellowish color as it approaches the yellow silt loam. It contains some fine sand, and locally, in small areas, quite ap- preciable amounts, but the principal constituent is silt of various grades. The organic-matter content is 2.28 percent, or about 23 tons per acre. The surface soil is porous and friable but “runs together” badly because of its shortage in organic matter and lime. The subsurface, like the surface, varies from a gray or yellowish gray to a yellow silt loam sufficiently porous to permit slow percolation ; its physical com- position is such that capillary movement takes place very readily. In thickness it varies from 6 to about 16 inches. The subsoil is a yellow or mottled grayish silt or clayey silt, somewhat compact but pervious. The depth to the natural subsoil is quite variable, owing to the amount of erosion that has taken place, but it commonly varies from 10 34 Soil Report No. 8 [October, to 20 inches. In places, both surface and subsurface have been removed, but this is unusual. The growth of natural vegetation on this type has done very little toward adding organic matter. In fact, it is more likely true that the growth of forest trees has reduced the content of this constituent in the original soil. At any rate, this type is now deficient in organic matter, and one of the most important problems in its management is to increase this constituent. In order to do this, a rotation must be carefully planned, and all crop residues and legume crops, or their equivalents in manure, put back on the land. Deep-rooting crops, such as red, mammoth, or sweet clover, should be grown; but in order to grow these successfully, applications of ground limestone are necessary. If the soil is to be enriched and its productive power increased and maintained in any per- manent way, phosphorus must also be applied, altho the application may well be delayed until, thru the use of limestone and the growth of clover, some or- ganic matter can be turned under; or else kainit should be applied with the phosphorus. Very marked improvement can be made with limestone and the organic matter which it helps to produce. Field experiments on yellow-gray silt loam in the lower Illinois glaciation were begun in 1910 in Saline county near Raleigh, where the people of the community have provided the University with a very suitable tract of this type of soil for a permanent soil experiment field. There, as an average of triplicate tests each year, the yield of corn on untreated land was 25.3 bushels per acre in 1910, 23.6 in 1911, and 22.0 in 1912, while on duplicate plots treated with six tons per acre of ground limestone and the limited amount of organic manures produced upon the land, the corresponding yields were 41.4 bushels in 1910, 41.3 in 1911, and 50.1 in 1912. These results show an average increase of 20.6 bushels, of which only 6.6 bushels are due to organic manures. As an average of duplicate tests with each crop each year for three years, the ground limestone increased the yields by 14 bushels of corn, 10.55 bushels of oats, .85 ton of hay (clover or cowpea), and 4.45 bushels of wheat. The value of these increases at 35 cents for corn, 30 cents for oats, 70 cents for wheat, and $6 for hay, amounts to $16.28 and corresponds to the value of the increase produced by limestone on one acre during a four-year rotation. Thus the limestone paid about 200 percent interest on the investment, and the ap- plication of 6 tons per acre is sufficient for about fifteen years, altho in order to maintain a liberal amount of limestone in the soil it is well to apply about 2 tons per acre every four or five years after making the heavier initial application. Owing to the low supply of active organic matter in the soil at Raleigh, phosphorus produced no benefit, as an average, during the first two years ; but with the turning under of the crop residues and farm manure in proportion to the crops produced, the effect of phosphorus is seen to some extent in the crops of 1912 and 1913. The fourth series of plots will receive its first farm manure for the 1914 crops, so that trustworthy data as to the benefits of orgapic matter, or of phosphorus combined with organic matter, will not be secured before the second rotation period. 1913 ] Bond County 35 Where kainit has been used at the rate of 200 pounds for each year, ap- plied in connection with phosphate and in addition to the 6 tons of limestone, the average increase for the kainit during the first three years has been $2.90, or only about half its cost. Yellow Silt Loam (335) Yellow silt loam in Bond county includes the broken, very rolling, and hilly land along the streams and sometimes on the steep slopes of ridges. It is best to keep much of it forested, tho when properly treated it makes good pasture land. It is so steeply sloping that little of it should ever be cultivated. When it is cultivated, the utmost care should be taken to prevent washing, which is the most serious danger to this type of soil. Already many fields have been ruined by gullying. This type of soil covers an area of 60.09 square miles (38,458 acres), or 16.15 percent of the county. The surface soil is a friable yellow silt loam varying somewhat with topography. The less broken areas are a grayish yellow, while the steep slopes are reddish yellow, or brownish yellow where a little more organic matter re- mains. As a rule, the soil contains enough fine sand to give it a fairly good tex- ture, but it is very deficient in organic matter, having only 2 percent, or 20 tons per acre. This condition contributes toward its excessive washing. ‘ ‘ Clay points,” or places where the top soil has been removed by washing, are quite common, and they are very unproductive. The subsurface varies in thickness; where little or no washing has taken place it is from 6 to 14 inches thick. It consists usually of a friable, slightly loamy, yellow silt, mottled with gray or with reddish blotches of iron oxid. The subsoil is usually a somewhat friable and quite pervious, yellow, clayey silt. Where much washing has occurred, the glacial drift frequently forms the subsoil. Of most importance in the management of this type is the prevention of much loss by washing. Erosion occurs as sheet-washing and gullying. Ordi- narily sheet-washing is not thought of as doing very much damage, but it is really the most injurious form of erosion. Gullying results in the absolute ruin of small areas, but sheet-washing reduces the productive capacity of large areas to such an extent that it prevents not only profitable cropping but even the growing of crops large enough to pay for their raising. Every means should be taken to prevent this loss. The steep, gullied slopes probably never can be reclaimed with profit for cropping purposes at the present average prices for labor and farm produce. The forests that originally covered these lands should never have been entirely removed. The only thing that made these lands valuable in the first place was the forests, and to make them of any future value they should be reforested. This has been done in a few cases and has met with excellent success. The ac- companying illustrations show such results. The black locust can be used most successfully for this purpose, as it is largely independent of the supply of nitroge- nous organic matter in the soil, altho it is subject, of course, to insect injury which is sometimes fatal. Where not in forest, the steep land should be kept in pasture as much as possible ; if cropped, it should be for only one or two years Soil Report No. 8 [October, 36 Plate 6. — Young Grove of Black Locust Trees on Rolling Hill Land in Johnson County, Illinois (Grown by J. C. B. Heaton) at a time and then the land should be reseeded for pasture. Live-stock is indis- pensable to general farming on this type of soil. Sheet-washing on the moderate slopes may be prevented to a great extent by the following methods: (1) By increasing the organic-matter content, thus binding together the soil particles and rendering the soil more porous. This can be done by apply- ing farm manure and plowing under stubble, straw, corn stalks, and legume crops, such as clover and cowpeas. (2) By deep plowing from seven to ten inches, in order to increase the absorption of water and diminish the run-off. Ten inches of loose soil will readily absorb two inches of rainfall without run-off. (3) By contour plowing. When land is plowed up and down the slope, as is often done in this state, dead furrows are made which furnish excellent beginnings for gullies. Even the little depressions between furrows aid in washing. On land subject to serious washing, plowing should always be done across the slope, on the contour, so that water will stand in the furrow without running in either direction. Every furrow will then act as an obstruction to the movement of water down the slope, thus checking the velocity of the water 1918 ] Bond County 37 \f ; - Plate 7. — Grove of Locust Trees About Twenty-five Years Old on Rolling Hill Land in Johnson County, Illinois (Grown by J. C. B. Heaton) and its power to wash, and also facilitating absorption and diminishing the amount of run-off. (4) By using cover crops to hold the soil during the winter and spring. Rye is a fairly good cover crop to sow in the corn during the late summer or early fall. Wheat, especially when seeded late, is a poor crop to grow on rolling land because it does not usually make sufficient growth in the fall to afford a good protection to the soil during winter. Of course both rye and wheat invite the development of chinch bugs. A mixture of winter vetch and clover with a few cowpeas, seeded at the time of the last cultivation of the corn, gives good results in favorable seasons. (See Circular 119, “Washing of Soils and Methods of Prevention.”) 38 Soil Report No. 8 [October, This yellow silt loam is markedly acid. Where cropping is practiced, lime- stone should be used liberally, especially for the benefit of clover grown to pro- vide nitrogen, in which this soil is very deficient, particularly where it has been long cultivated and thus exposed to surface washing. On such land nitro- gen is the element which now first limits the growth of grain crops, as will be seen from Plates 8 and 9 and Tables 14 and 15. In one experiment, a large quantity of the typical worn hill soil was col- lected from two different places. 1 Each lot of soil was thoroly mixed and put in ten four- gallon jars. Ground limestone was added to all the jars except the first and last in each set, those two being retained as control or check pots. The elements nitrogen, phosphorus, and potassium were added singly and in combination, as shown in Table 14. As an average, the nitrogen applied produced a yield about eight times as large as that secured without the addition of nitrogen. While some variations in yield are to be expected, because of differences in the individuality of seed Plate 8. — Wheat in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (See Table 14) Table 14. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (Grams per pot) Pot No. Soil treatment applied Wheat Oats 1 None 3 5 2 Limestone 4 4 3 Limestone, nitrogen 26 45 4 Limestone, phosphorus 3 6 5 Limestone, potassium 3 5 6 Limestone, nitrogen, phosphorus 34 38 7 Limestone, nitrogen, potassium 33 46 8 Limestone, phosphorus, potassium 2 5 9 Limestone, nitrogen, phosphorus, potassium 34 38 10 None 3 5 Average yield with nitrogen 32 42 Average yield without nitrogen 3 5 Average gain for nitrogen 29 37 1 Soil for wheat pots from loess-covered unglaciated area, and that for oat pots from upper Illinois glaciation. 191S ] Bond County 39 or other uncontrolled causes, yet there is no doubting the plain lesson taught by these actual trials with growing plants. The question arises next, Where is the farmer to secure this much-needed nitrogen? To purchase it in commercial fertilizer would cost too much; indeed, under average conditions the cost of the nitrogen in such fertilizers is greater than the value of the increase in crop yields. There is no need whatever to purchase nitrogen, for the air contains an inexhaustible supply, which, under suitable conditions, the farmer can draw upon, not only without cost, but with profit in the getting. Clover, alfalfa, cowpeas, and soybeans are not only worth raising for their own sake, but they have power to secure nitrogen from the atmosphere if the soil contains lime- stone and the proper nitrogen-fixing bacteria. In order to secure further information along this line, another experiment with pot cultures was conducted for several years with the same type of worn hill soil as that used for the wheat cultures described above. The results are reported in Table 15. To three pots (Nos. 3, 6, and 9) nitrogen was applied in commercial form, at an expense amounting to more than the total value of the crops produced. In three other pots (Nos. 2, 11, and 12) a crop of cowpeas was grown during the late summer and fall and turned under before the wheat or oats were planted. Pots 1 and 8 served for important comparisons. After the second catch crop of cowpeas had been turned under, the yield from Pot 2 exceeded Plate 9. — Wheat in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (See Table 15) Table 15. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land and Nitrogen-Fixing Green Manure Crops (Grams per pot) Pot No. Soil treatment 1903 Wheat 1904 Wheat 1905 Wheat 1906 Wheat 1907 Oats 1 2 11 12 None Limestone, legume Limestone, legume, phosphorus Limestone, legume, phosphorus, potassium . . 10 14 16 4 17 19 20 4 26 ■ 20 21 4 19 18 19 6 37 27 30 3 Limestone, nitrogen 17 14 15 9 28 6 Limestone, nitrogen, phosphorus 26 20 18 18 30 9 Limestone, nitrogen, phosphorus, potassium. 31 34 21 20 26 8 Limestone, phosphorus, potassium 3 3 5 3 7 40 Soil Report No. 8 [ October , that from Pot 3 ; and in the subsequent years the legume green manures pro- duced, as an average, rather better results than the commercial nitrogen. This experiment confirms that reported in Table 14, in showing the very great need of nitrogen for the improvement of this type of soil; and it also shows that nitrogen need not be purchased, but that it can be obtained from the air by growing legume crops and plowing them under as green manure. Of course the soil can be very markedly improved by feeding the legume crops to live stock and returning the resulting farm manure to the land, if crops of legumes are grown frequently enough and if the farm manure produced is sufficiently abundant and is saved and applied with care. When this type of soil is to be prepared for seeding down, it may well be treated with five tons per acre of ground limestone, in order to encourage the growth of clover and thus make possible the accumulation of nitrogen, the element in which this type is most deficient wherever it has been long under cultivation. As a rule, it is not advisable to try to enrich this soil in phosphorus, because of the fact that erosion, which is sure to occur to some extent, will renew the supply from the subsoil. Field experiments covering nine years have been conducted on the yellow silt loam at Vienna, Johnson county. Here heavy applications of ground lime- stone paid nearly 200 percent on the investment, and about half the limestone applied still remained in the soil for the benefit of later crops. Neither phos- phorus nor potassium produced sufficient increase to pay the cost. (The details of these investigations are reported in Soil Report No. 3, “Hardin County Soils.”) One of the most profitable crops to grow' on this land is alfalfa. To get alfalfa well started requires a liberal use of limestone, thoro inoculation with nitrogen-fixing bacteria, and a moderate application of farm manure. If ma- nure is not available, it is well to apply about 500 pounds per acre of acid phos- phate or steamed bone meal, mix it with the soil, by disking if possible, and then plow it under. The limestone (about 5 tons) should be applied after plowing and mixed with the surface soil in the preparation of the seed bed. The special purpose of this treatment is to give the alfalfa a quick start in order that it may grow rapidly and thus protect the soil from washing. Light Gray Silt Loam on Tight Clay (332) Light gray silt loam on tight clay occurs in old timbered regions where the land is so nearly level that there is no chance for rapid surface drainage. It is the most common level timber land of Bond county and occupies a total area of 16.45 square miles (10,528 acres), or 4.42 percent of the county. The type has two distinct phases: one phase is slightly better surface-drained, but lighter colored and less productive; the other is more swampy (water oaks com- monly grow on this phase), with a darker surface and a greater porosity, so that better drainage is probably possible. The amount of this latter phase is small as compared with the former and is frequently confined to narrow strips too small to map. 191S ] Bond County 41 “Scalds” are found on this type, but they are not so common as on the gray silt loam on tight clay (330) or the brown-gray silt loam on tight clay (328). The surface soil of this type, 0 to 6% inches, is a light gray to almost white silt loam containing 1.6 percent of organic matter, or 16 tons per acre. It is somewhat porous and incoherent, but contains sufficient clay to bake when puddled and dried. When the moisture content is at its optimum, the soil works very well, but because of the low organic-matter content it “runs to- gether” badly with rains or with freezing and thawing when wet. The surface soil, as well as the subsurface and subsoil, contains large numbers of iron oxid concretions of various sizes up to one-fourth inch in diameter. Small pebbles of quartz are sometimes found, possibly having been brought to the surface from the underlying glacial till by burrowing animals during past centuries. The subsurface varies from light gray silt loam to a white silt, compact but friable, from 2 to 20 inches in thickness. Water passes thru it slowly. The subsoil consists of a compact yellowish gray clayey silt, or silty clay, only slowly pervious to water, but usually not quite so tight as the correspond- ing layer of the gray silt loam on tight clay (330). In places the type has a somewhat more friable subsoil which is not so nearly impervious as the sub- surface. Where the tight clay occurs at the greater depths from the surface, it is less objectionable. An invoice of plant food shows great need of nitrogen and phosphorus. With provision made for these, with a liberal use of limestone and organic matter, including legume residues or farm manure, and with proper surface drainage, the soil can be made highly productive. White Silt Loam on Tight Clay (332.1) White silt loam on tight clay is found on the level upland, and it is now or was formerly covered by a growth of stunted trees, principally the so-called post oak. The term post-oak flat or post-oak soil is commonly applied to this type, altho these terms are often used locally to designate the poorer phase of light gray silt loam on tight clay (332). The surface drainage is very poor and the subsoil is almost impervious. The total mapped area of this type in the county is only 435 acres, but there are many small areas that cannot be shown on the map. Much of the light-gray silt loam on tight clay (332) grades toward this related type (332.1). Where land of this type has been cultivated, the surface soil, 0 to 6% inches, is a white silt; in the timbered areas this characteristic white silt is sometimes overlain by an inch or two of dark gray silt loam. The organic- matter content of this layer is even lower in this type than in the light gray silt loam, containing only 1.25 percent, or 12.5 tons per acre. Because of this lack of organic matter and the high silt content, the soil “runs together” badly. Iron oxid concretions are always present. The subsurface layer is a white silt with many iron oxid concretions. It varies from 4 to 16 inches in thickness and passes abruptly into the subsoil. The subsoil is a light yellow,- iron-stained, silty clay, very tough and plastic when wet and hard when dry, with an organic-matter content of only .30 percent. Both subsurface and subsoil are almost impervious. 42 Soil Report No. 8 [ October , The first need of this soil is ground limestone, the initial application of which may well be 4 to 6 tons per acre. The increase in organic matter should follow as rapidly as practicable. Legumes, such as cowpeas, clover, and sweet clover, should be grown and turned under with farm manure and crop residues, such as straw and corn stalks. For such flat, poorly drained land, alsike is usually a more satisfactory crop than red clover. Finally, phosphorus should be used liberally in connection with the organic matter in order to provide a permanent system of soil improvement. (c) Ridge Soils Yellow Silt Loam (235) The morainal ridges of the lower Illinois glaciation have given a slight variation to the usual level topography of this region, their height varying from 20 to 100 feet or more. A fine covering of loess from 5 to 10 feet deep, together with excellent drainage, has resulted in the formation on these ridges of a soil known as yellow silt loam, very different from the surrounding prairie but somewhat resembling in texture the better phase of the yellow silt loam timber land (335) already described. The total area of this type in Bond county is 12.41 square miles (7,942 acres) or 3.33 percent of the county. The surface soil, 0 to 6% inches, is a yellow or yellowish brown silt loam with a considerable amount of very fine sand. The color varies with the amount of erosion that has taken place. Where little washing has occurred, the color may be a yellowish brown, while with more washing it becomes yellow. The soil is loose, porous, and readily pervious to water. Its physical composition is such as to give it great water-retaining power and strong capillarity, so that it will resist drouth well if properly cultivated. The organic-matter content is about 1.8 percent, or 18 tons per acre. The subsurface layer, extending from 6% to about 20 inches below the surface, varies from a yellowish brown silt loam to a yellow silt or a slightly clayey silt. It becomes more compact with depth but still retains its pervious- ness and capillary power. The upper part of the subsoil is somewhat compact and slightly clayey, but it passes into a friable silt containing some fine sand. It is yellow or reddish yellow in color. Below 24 inches it is sometimes slightly gray or marked with gray blotches, and when grading toward yellow-gray silt loam (334) it becomes decidedly gray in places. This soil, considered from a physical standpoint, is almost as good as could be desired. In respect to aeration, drainage, and ability to withstand drouth, it is one of the best upland types in the county. The organic-matter content should be increased by growing clovers and cowpeas, and these should be turned under directly or as farm manure, together with crop residues, straw, and corn stalks. The maintenance of organic matter is made more difficult because of the rolling character of the land, which facili- tates erosion and the removal of the best soil. This ridge soil contains no limestone. As a rule the subsoil is markedly acid, but with a liberal use of limestone and thoro inoculation it becomes a very good soil for alfalfa, altho where badly worn manure may well be used in getting the alfalfa started. (See also discussion of yellow silt loam, No. 335.) 1913] Bond Coonty 43 Gray -Red Silt Loam on Tight Clay (233) Gray-red silt loam on tight clay occurs on some of the ridges, which are in part at least of preglacial origin, rising from 5 to 75 feet above the sur- rounding upland. As a rule, it is one of the poorest upland types in the state, but most of the areas in this county are a better phase of the type than ordinary. This type in Bond county occupies 922 acres. In some places it may suffer from erosion, but it is extremely doubtful whether tile-drainage would profitably benefit this soil, — at best, not until other methods of improvement have been put into practice. The surface soil is a friable gray silt loam very similar to that of the gray silt loam on tight clay (330). The subsurface layer also resembles the corresponding stratum in gray silt loam on tight clay both in texture and thickness, but it contains more of the higher oxid of iron, which gives it a reddish color. As a rule, the organic- matter content is low. The subsoil lies from 7 to 20 inches below the surface and consists of a layer of very plastic, gummy, almost impervious red clay, varying from 4 to 12 inches in thickness and underlain by a less plastic and more silty stratum. When dry, the red clay becomes so hard that it is next to impossible to bore into it with an auger. Where this layer appears at the surface, as it does on some small eroded areas, the land is practically worthless. This type of soil closely resembles the more extensive gray silt loam on tight clay (330). Methods for its improvement are the same, except on areas sub- ject to considerable erosion, where the addition of phosphorus is not advised. This factor of erosion, together with the tighter texture, as a rule will make the improvement of this type less satisfactory than that of the gray silt loam. Yellow Fine Sandy Silt Loam (245) Yellow fine sandy silt loam occupies some of the highest glacial ridges, which have been covered with a deposit of loess varying from 10 to 20 feet in thickness and of slightly coarser grade than the surrounding deposits. The type has always been well drained and as a result is well oxidized. Practically all of it was originally forested. The total area in Bond county is almost 2 square miles (1,267 acres), or .53 percent of the county. The surface soil, 0 to 6% inches, is a brownish yellow to a yellowish brown silt loam containing from 25 to 35 percent of fine sand. It also contains much coarse silt. This mixture furnishes the basis for an ideal soil. It is easy to work, porous, and at the same time has great water-retaining power and strong capillarity, so that it will resist drouth well when properly cared for. The organic-matter content is about 2 percent, or 20 tons per acre. The subsurface layer varies from a yellowish brown to a yellow silt loam, containing slightly more clay than the surface soil. It becomes somewhat more compact with depth, but still retains its perviousness and capillary power. The upper part of the subsoil is a somewhat compact, clayey silt, but it passes into a very pervious friable silt containing considerable amounts of fine sand and coarse silt. It is yellow or reddish yellow in color and rarely con- tains the gray blotches which are so common in yellow silt loam (235). 44 Soil Report No. 8 [October, From a physical standpoint this type is the best upland soil in the county. As a rule it is low in organic matter and slightly acid. The organic matter should of course be increased, altho the rolling character of the type renders this problem difficult. Like most soils that are subject to much erosion, this type is poor in nitro- gen and rich in potassium. The supply of phosphorus is low but it increases with depth, so that erosion enriches the soil in that constituent. For this rea- son and also because of the extensive feeding range afforded by the porous character of the soil, the addition of phosphorus is not advised. Very marked and profitable improvement can be made with the use of limestone and legumes, and these means are sufficient to provide for permanent systems of moderately high production. (d) Bottom-Land Soils Deep Gray Silt Loam (1331) Deep gray silt loam occurs along most of the streams of the lower Illinois glaciation. It is formed from the gray, yellow-gray, and yellow silt loams that have washed down from the upland and blended into a gray or yellowish gray soil. During floods these lands in most places still receive frequent or oc- casional deposits of new material. Aside from the difficulties from overflow and lack of drainage, this is the most valuable extensive soil type in Bond county. • This type occupies a total area of 26.22 square miles (16,781 acres), or 7.05 percent of the county. It lies so low that the drainage is generally poor, and there is often much difficulty in getting sufficient outlet for under-drainage or sometimes even for adequate surface drainage. Where a satisfactory outlet can be secured, tile drainage greatly benefits this soil. The surface soil is a gray silt loam, varying from a gray to a drab in color and from a loam to a clayey silt loam in physical composition. The subsurface and subsoil are about the same as the surface except that they are lighter in color and commonly a little more clayey with depth. In the smaller stream bottoms, the recent deposits are frequently yellow and slightly sandy, and consequently there is found in places a stratum of yellow on the gray, varying from a few inches to a foot or more in thickness. In phosphorus content, this type exceeds the most common prairie soil of the corn belt. The porous subsoil affords such a deep feeding range that the application of that element is not likely to give profitable returns, except where overflow is not common and where the soil has been long cropped. The soil of this type is acid. It is also rather poor in nitrogen, altho this deficiency is counterbalanced to a large extent by the great depth and porosity of the soil. While the overflow and drainage problems are of first importance, where these are under sufficient control to permit of soil improvement the use of lime- stone and the addition of nitrogenous organic matter, such as clover or manure plowed under, will make this soil still more productive ; and if the land is pro- tected from the usual overflow deposits, the addition of phosphorus will ulti- mately be necessary; even now it is likely to be profitable for the highest im- 19JS] Bond County 45 provement of the soil. To illustrate, it may be pointed out that on the Uni- versity Farm at Urbana, land that has yielded 72.5 bushels of corn per acre as a six-year average, in a rotation of corn, oats, and clover, with limestone and organic manures provided, has with the addition of phosphorus made an aver- age of 88.5 bushels during the same years. Thus there may be room for phos- phorus “at the top,” even where very satisfactory yields may be secured with- out its application and where other factors are of first importance. Deep Brown Silt Loam (1326) The basic material for the deep-brown silt loam naturally belongs to the middle Illinois glaciation with its dark-colored upland soils, but this has been covered by loads of dark sediment brought down by Shoal creek and its tribu- taries and deposited over their flood plains. This sediment has been more or less mixed with material brought in by small streams from the light-colored upland soils, resulting in the formation of soils intermediate in character or lacking in uniformity. The bottoms along the streams vary in width from a few rods to more than a mile. ' The soil of the narrower bottoms has a tendency to be darker than that of the wider areas. This type occupies 13.74 square miles (8,794 acres), or 3.7 percent of the area of Bond county. In topography it is flat or with very slight undulations that represent old stream or overflow channels. Better drainage is needed in much of this area. The surface soil, 0 to 6% inches, is a brown silt loam, varying in places, especially in the flat, poorly drained areas, to a gray silt loam. While the organic-matter content of this type is not high, yet it is more easily maintained here than in the upland because of the occasional overflow and the consequent deposition of material rich in organic matter. The physical composition of this soil varies from a heavy silt loam to a sandy loam, but the areas of these extreme types, especially the latter, are so small and so changeable that it would not mean much to show them on the map, as the next flood might change their boundaries. The subsurface varies from a brown silt loam-to a gray silt loam. The subsoil varies in color from a brown to a yellowish drab, and in physical composition from a clayey silt to a sandy loam or sometimes even a sand in the lower subsoil. Under the usual conditions it is very doubtful whether any materials can be applied to this soil with profit, but where feasible some legumes should be grown in the crop rotation. 46 Soil Report No. 8 [October, APPENDIX A study of the soil map and the tabular statements concerning crop require- ments, the plant-food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil im- provement, and a careful study of the discussion of general principles and of the descriptions of individual soil types, will furnish the most necessary and use- ful information for the practical improvement and permanent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and important soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility in Illinois Soils,” which contains a colored general soil-survey map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils’’ Bulletin No. 94, “Nitrogen Bacteria and Legumes” Bulletin No. 115, “Soil Improvement for the Worn Hill Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois ’ ’ Circular No. 82, “Physical Improvement of Soils” Circular No. 110, “Ground Limestone for Acid Soils” Circular No. 127, “Shall We Use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, ‘ ‘ Results of Scientific Soil Treatment ’ ’ and ‘ ‘ Methods and Results of Ten Years’ Soil Investigation in Illinois” Circular No. 165, “Shall We Use ‘Complete’ Commercial Fertilizers in the Corn Belt?” Circular No. 167, “The Illinois System of Permanent Fertility” Note. — Information as to where to obtain limestone, phosphate, bone meal, and potas- sium salts, methods of application, etc., will also be found in Circulars 110 and 165. Soil Survey Methods The detail soil survey of a county consists essentially of ascertaining, and indicating on a map, the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential: first, careful, well-trained men to do the work; second, an accurate base map upon which to show the results of the work; and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the' work must be able to keep their location exactly and to recognize the different soil types, with their principal variations and lim- its, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will sur- vey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries must match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil mapping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construc- tion of these maps, while the most trustworthy county map available is used in 1918 ] Bond County 47 locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and corrected if wrongly located. In order to make these verifications and corrections, each survey party is pro- vided with an odometer for measuring distances, and a plane table for deter- mining directions of angling roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, ditches, streams, and necessary corrections are placed in their proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map, and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils for this purpose being carried in the field. A small auger 40 inches long foi^ns for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is carried by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while distances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be located with as high a degree of ac- curacy as can be indicated by pencil on the scale of one inch to the mile. Soil Characteristics The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type grades into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, al- luvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) the native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil ; ( 5 ) the physical, or me- chanical, composition of the different strata composing the soil, as the percent- ages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) the agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. The common soil constituents are indicated in the following outline : Soil constituents Organic | matter - Inorganic matter ("Comprising undecomposed and partially decayed | vegetable or organic material Clay 001 mm. 1 and less Silt 001 mm. to .03 mm. Sands 03 mm. to 1. mm. Gravel 1. tnm. to 32 mm. Stones 32. mm. and over Further discussion of these constituents is given in Circular 82. *25 millimeters equal 1 inch. 48 Soil Report No. 8 [October, Groups of Soil Types The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand. Some silt and a little clay may be present. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams— Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 25 to 50 percent of gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel and much sand. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Bock outcrop— Usually ledges of rock having no direct agricultural value. More or less organic matter is found in all the above groups. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop ; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which it is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly important, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually pres- ent in the soil strata sampled and analyzed, but the rate of liberation is gov- erned by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are limestone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may be supplied also by green- manure crops and crop residues, such as clover, cowpeas, straw, and corn stalks. The rate of decay of organic matter depends largely upon its age and origin, 191S ] Bond County 49 and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which represents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly 20 tons of organic matter. But this organic mat- ter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or ccwpeas plowed under may have greater power to liberate plant food than the 20 tons of old, inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent addi tions of active organic matter, whether in applications of farm manure, in legume crops, or in grass-root sods of old pastures. Probably no agricultural fact is more generally known by farmers and land- owners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that with the normal rainfall of Illi- nois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such commodity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts of potassium, magnesium, calcium, etc., for the use of the growing crop. As already explained, fresh organic matter decomposes much more rapidly than old humus, which represents the organic residues most resistant to decay and which consequently has accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porus condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old, resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and thus furnish or lib- erate organic matter and inorganic food for bacteria, the bacteria, under such favorable conditions, appearing to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when composted with, fresh farm manure ; so that two tons of the compost 1 may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bac- terial action is also promoted by the presence of limestone. 'In his book, “Fertilizers,” published in 1839, Cuthhert W. Johnson reported such com- post to have been much used in England and to be valued as highly, “weight for weight, as farm-yard dung.” so Soil Keport No. 8 f October, The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter ; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil ; while in old, worn soils that are greatly in need of fresh, active, organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. Soils of cut-over or burnt-over timber lands sometimes contain so much partially decayed wood or charcoal as to destroy the value of the. nitrogen-carbon ratio for the purpose indicated. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches, among our common agricultural plants) secure from the soil alone six elements (phos- phorus, potassium, magnesium, calcium, iron, and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a build- ing is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay ; and, where the land is properly drained and properly tilled, such crops would fre- quently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the absolute needs of the crops. Crop Requirements The accompanying table shows the requirements of wheat, corn, oats, and clover for the five most important plant-food elements which the soil must fur- nish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed" by plants, so that they are never known to limit the yield of general farm crops grown under normal conditions.) 1913] Bond County 51 Table A. — Plant Food in Wheat, Corn, Oats, and Clover Produce Nitro- Phos- Potas- Magne- Cal- Kind Amount gen phorus sium sium cium lbs. lbs. lbs. lbs. lbs. Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw. 2% tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs % ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2% tons 31 5 52 7 15 Clover seed 4 bu. 7 2 3 1 1 Clover hay 4 tons 160 20 120 31 117 Total in grain and seed 244 1 42 51 16 4 Total in four crops.. 510 1 77 322 68 168 I These amounts include the nitrogen contained in the clover seed or hay, which, how- ever, may be secured from the air. To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as possible with profit ? Among the four .crops, corn is the largest, with a total yield of more than six tons per acre; and yet the 100-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with lime- stone, phosphorus, and manure). The importance of maintaining a rich surface soil cannot be too strongly emphasized. This is well illustrated by data from the Rothamsted Experiment Station, the oldest in the world. On Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well ferti- lized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (0 to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods op Liberating Plant Food Limestone and decaying organic matter are the principal materials which the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, eowpeas, and other legumes, but also the nitrifying bacteria, which have power to transform the insoluble and unavailable organic 52 Soil Report No. 8 [October, nitrogen into soluble and available nitrate nitrogen. At the same time, the products of this decomposition have power to dissolve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing what- ever to the soil, but always leaves it poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed-bed for root development and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows: (1) If the soil is acid, apply at least two tons- per acre of ground lime- stone, preferably at times magnesian limestone (CaC0 3 MgC0 3 ), which con- tains both calcium and magnesium and has slightly greater power to correct soil acidity, ton for ton, than the ordinary calcium limestone (CaC0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years. On strongly acid soils, or on land being prepared for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks), or by using for feed and bed- ding practically all the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines: First year, corn. Second year, corn. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rotation. In grain farming, with small grain grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five- year rotation by cutting out either the second or the sixth year, and to a four- year system by omitting the fifth and sixth years. LUIS] Bond County 53 With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four ; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover; or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are; Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat, (4) clover, and (5) wheat (and clover) allows legumes to be seeded four times. Alfalfa may be grown on a sixth field for five or six years in the combination rotation, alternating between two fields every five years, or rotating over all the fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute sweet clover or alsike for red clover in about every third rotation, and at the same time to discontinue its use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover crop (seeded at the last cultivation) in the southern part of the state, and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named: 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires 1% pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. 1 ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. In grain crops, such as wheat, corn, and oats, about two-thirds of the nitrogen is contained in the grain and one- third in the straw or stalks. (See also discussion of “The Potassium Problem,” on pages following.) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in consid- erably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far secured shows posi- tively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil 54 Soil Report No. 8 [October, improvement. The first application may well be one ton per acre, and subse- quently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total application of from three to five or six tons per acre of raw phosphate containing 121/2 percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in carload lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phos- phate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about 11/2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rota- tion, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply of decaying organic matter has been made adequate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or a mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phos- phorus as well as to furnish available potassium and magnesium, and for a few years such use of kainit may be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for supplying decaying organic matter, since this will necessitate returning to the soil the potassium contained in the crop residues from grain farming or the manure produced in live-stock farming, and will also provide for the liberating of- potas- sium from the soil. (Where hay or straw is sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow-gray silt loam and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tends to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently; but where such lands are farmed under such a system, not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time; and where the soil is acid a liberal use of limestone, as top- dressings if necessary, and occasional reseeding with clovers will benefit both the pasture and indirectly the grain crops. Bond County 55 191S~\ Advantage of Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years; but even a partial stand of clover the first time will probably provide a thousand times as many bacteria for the next clover crop as one could afford to apply in artificial inoculation, for a single root-tubercle may contain a million bacteria developed from one during the sea- son’s growth. This is only one of several advantages of the second course of the rotation over the first course. Thus the mere practice of crop rotation is an advantage, especially in helping to rid the land of insects and foul grass and weeds. The clover crop is an advantage to subsequent crops because of its deep-rooting char- acteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage ; and in systems of permanent soil improve- ment, such as are here advised and illustrated, more limestone and more phos- phorus are provided than are needed for the meager or moderate crops pro- duced during the first rotation, and consequently the crops in the second rota- tion have the advantage of such accumulated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. This means that these systems tend positively toward the making of richer lands. The ultimate analyses recorded in the tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter ; and the accumulated information from careful and long-continued investigations in different parts of the United States clearly establishes the fact that in general farming these essen- tials can be supplied with greatest economy and profit by the use of ground nat- ural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applica- tions are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt, such as kainit, is used, it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 60 years (1852 to 1911), the yield of wheat was 12.7 bushels on untreated land and 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied. As further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of magnesium raised it to 29.2 bushels; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied, the wheat crop removed an- 56 Soil Report No. 8 [' October , nually an average of 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained an abundance of lime- stone, but no organic matter was provided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 60 years (1852 to 1911) was 14.2 bushels on untreated land, 38.1 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus were applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.5 bushels. Where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average was 43.0 bushels. Thus, as an average of 60 years, the use of sodium produced 1.8 bushels less wheat and 1.5 bushels more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop ; but this must be expected to occur in time where no potassium is returned in straw or manure, and no pro- vision made for liberating potassium from the supply still remaining in the soil. If the wheat straw, which contains more than three-fourths of the potassium removed in the wheat crop (see Table A), were returned to the soil, the neces- sity of purchasing potassium in a good system of farming on such land would be at least very remote, for the supply would be adequately maintained by the actual amount returned in the straw, together with the additional amount which would be liberated from the soil by the action of decomposition products. While about half the potassium, nitrogen, and organic matter, and about one-fourth the phosphorus contained in manure is lost by three or four months’ exposure in the ordinary pile in the barn yard, there is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while in average live-stock farming the animals destroy two-thirds of the or- ganic matter and retain one-fourth of the nitrogen and phosphorus from the food they consume, they retain less than one-tenth of the potassium ; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 6% inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent cul- tivation) will permanently maintain the potassium in grain farming by re- newal from the subsoil, provided one-third of the potassium is removed by crop- ping before the soil is carried away. From all these facts it will be seen that the potassium problem is not one of addition but of liberation; and the Rothamsted records show that for many years other soluble salts have practically the same power as potassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this Bond County 57 19 IS] action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other ele- ments, is not known, but where much potassium is removed, as in the entire crops at Rothamsted, with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909, and 1910 on the Fairfield experiment field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium and costing $5.10, increased the yield of corn by 9.3 bushels per acre ; while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit paid for itself ; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield included an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure were applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bushels, while the 600 pounds of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was produced by the addition of either' potassium sulfate or kainit; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for, and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant-food elements, especially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown by chemical analysis that potassium salts and most other soluble salts increase the solubility of the phosphorus in soil and in rock phosphate; also that the addition of glucose with rock phosphate in pot-culture experiments increases the availability of the phosphorus, as measured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the or- ganic matter of the food they consume, it it easy to determine from Table A that more organic matter will be supplied in a proper grain system than in a strictly live-stock system; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious interference with the capillary movement of the soil moisture, a common danger from plowing under too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming or when both grain and straw are sold, of course the draft on potas- sium will then be so great that in time it must be renewed by some sort of appli- cation. As a rule, farmers following this practice ought to secure manure from town, since they furnish the bulk of the material out of which manure is pro- duced. 58 Soil Report No. 8 [October, Calcium and Magnesium When measured by the actual crop requirements for plant food, magnesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses 1 of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of cal- cium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of magnesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in 1905. Prac- tically the same amount of calcium was found, by analyses, in the Rothamsted drainage waters. Common limestone, which is calcium carbonate (CaC0 3 ), contains, when pure, 40 percent of calcium, so that 800 pounds of limestone are equivalent to 320 pounds of calcium. Where 10 tons per acre of ground limestone were applied at Edgewood, Illinois, the average annual loss during the next ten years amounted to 790 pounds per acre. The definite data from careful investigations seem to be ample to justify the conclusion that where limestone is needed at least 2 tons per acre should be applied every 4 or 5 years. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. (See Soil Report No. 1.) Thus limestone has a positive value on some soils for the plant food which it supplies, in addition to its value in correcting soil acidity and in improving the physical condition of the soil. Ordinary lime- stone (abundant in the southern and western parts of the state) contains nearly 800 pounds of calcium per ton; while a good grade of dolomitic limestone (the more common limestone of northern Illinois) contains about 400 pounds of cal- cium and 300 pounds of magnesium per ton. Both of these elements are fur- nished in readily available form in ground dolomitic limestone. Reported by Doctor Bartow and associates, of the Illinois State Water Survey. UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 9 LAKE COUNTY SOILS By CYRIL G. HOPKINS, J. G. MOSIER, E. VAN ALSTINE, and F. W. GARRETT URBANA, ILLINOIS, APRIL, 1915 State Advisory Committee on Soil Investigations Ralph Allen, Delavan A. N. Abbott, Morrison F. I. Mann, Gilman J. P. Mason, Elgin C. V. Gregory, 538 S. Clark Street, Chicago Agricultural Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief Soil Survey — J. G. Mosier, Chief A. F. Gustafson, Associate S. Y. Holt, Associate H. W. Stewart, Associate H. C. Wheeler, Associate F. A. Fisher, Assistant F. M. W. Wascher, Assistant R. W. Dickenson, Assistant G. E. Gentle, Assistant O. I. Ellis, Assistant H. A. deWerff, Assistant E. F. Torgerson, Assistant Soil Analysis — E. Van Alstine, Associate J. P. Aumer, Associate W. H. Sachs, Associate Gertrude Niederman, A_3sista: W. R. Leighty, Assistant C. B. Clevenger, Assistant Agronomy and Chemistry Soil Experiment Fields — J. E. Whitchurch, Associate E. E. Hoskins, Associate F. C. Bauer, Associate F. W. Garrett, Assistant H. C. Gilkerson, Assistant H. F. T. Fahrnkopf, Assistant H. J. Snider, Assistant Soil Biology — A. L. Whiting, Associate W. R. Schoonover, Assistant Soils Extension — C. C. Logan, Associate INTRODUCTORY NOTE About two-thirds of Illinois lies in the corn belt, where most of the prairie lands are black or dark brown in color. In the southern third of the state, the prairie soils are largely of a gray color. This region is better known as the wheat belt, altho wheat is often grown in the corn belt and com is also a com- mon crop in the wheat belt. Moultrie county, representing the corn belt ; Clay county, which is fairly representative of the wheat belt ; and Hardin county, which is taken to repre- sent the unglaciated area of the extreme southern part of the state, were se- lected for the first Illinois Soil Reports by counties. While these three county soil reports were sent to the fetation’s entire mailing list within the state, sub- sequent reports are sent only to those on the mailing list who are residents of the county concerned, and to any one else upon request. Each county report is intended to be as nearly complete in itself as it is practicable to make it, and, even at the expense of some repetition, each will contain a general discussion of important fundamental principles in order to help the farmer and landowner understand the meaning of the soil fer- tility invoice for the lands in which he is interested. In Soil Report No. 1, “Clay County Soils,” this discussion serves in part as an introduction, while in this and other reports, it will be found in the Appendix ; but if necessary it should be read and studied in advance of the report proper. LAKE COUNTY SOILS By CYRIL G. HOPKINS, J. G. HOSIER. E. VAN ALSTINE, and P. W. GARRETT Lake county is located in the northeast corner of Illinois in the late Wis- consin glaciation, and is covered with a deposit of material made by the Lake Michigan glacier during its two stages. The topography of the county, tho quite rolling in many parts, is due almost entirely to the very irregular deposition of material by this glacier. Two distinct morainal areas occur. The one known as the Lake Border morainic system occupies the eastern part of the county and extends southward in the form of two low ridges, one near the lake and an- other just east of the Des Plaines river; the other, the Valparaiso morainic sys- tem, occupies the western part of the county. The latter reaches an altitude of about 300 feet above Lake Michigan. These morainic areas are marked by large numbers of kettle-holes, or basin-like depressions, that in the most rolling parts sometimes have a depth of 75 feet. Numerous lakes are found in the Valparaiso morainic system. The drift deposited by the Lake Michigan glacier over the county has a minimum depth of probably 150 feet, while the thicker deposits are between 300 and 400 feet. Leverett, in Monograph 38 of the United States Geological Sur- vey, states that the deposit of drift averages more than 200 feet in thickness over the county.. Borings indicate the presence of still older glacial drift beneath that of the late Wisconsin. Physiography Lake county is divided into two distinct drainage systems — one sloping into Lake Michigan and comprizing probably not more than one-fifteenth of the total area of the county, and a second, drained by the Des Plaines and the Fox rivers, into the Illinois. The large number of lakes and swamps in this county indicate very late drainage systems, so late that practically all of the lowland is occupied either by lakes or by swamps. The streams have not had time to form valleys sufficiently deep for draining these low areas. There are about fifty lakes in the county large enough to be shown on the soil map, many of which are sur- rounded, or nearly so, by swamps containing deposits of peat. The altitudes of some places in the county above sea level are as follows: Antioch, 770 feet; Aptakisic,~682 ; Diamond Lake, 760; Fox Lake, 745; Gilmer, 810; Gray’s Lake, 799 ; Gurnee, 677; Highland Park, 691; Lake Bluff, 683; Lake Villa, 796; Lake Zurich, 873; Leithton, 723; Libertyville, 670; Loon Lake, 783 ; Prairie View, 694; Rodont, 676; Russell, 677 ; Volo, 890; Wadsworth, 673; War- l Soil Report No. 9 [April, renton, 710; Waukegan (C. & N. W.), 596. A bench mark on the east entrance of the courthouse at Waukegan is 668.4 feet. The mean altitude of the water of Lake Michigan is 581 feet above sea level. Soil Material and Soil Types The Lake Michigan glacier left a deposit of boulder clay (a mixture of boulders, gravel, sand, silt, and clay), which has been transformed into soil in some places ; but the larger part of the county subsequently received a shallow deposit of 12 to 40 inches of loessial material formed from the fine rock flour produced by the grinding action of the glacier. This has been reworked by the wind and water and now covers the level and less rolling areas to an average depth of 16 to 20 inches. Beneath this is often found a stratum a few inches in thickness which contains a great many gravel, indicating the washing out of the fine material before the loess was deposited. From Waukegan to the state line a deposit has been formed by Lake Chicago which consists of a series of sand ridges only a few rods apart that have very little argricultural use. Be- tween these ridges peat deposits are frequently found. Table 1. — Soil Types of Lake County Soil type No. Name of type Area in square miles Area in acres Percent of total area 1026 l 1226 f 1060 | 1260 f (a) Upland Prairie Soils (page 23) Brown silt loam 1 Brown sandy loam 137.50 2.88 88 001 1 844 28.48 .60 1034 j 1234 .f 1035 1235 f 1064 1064.4 1081 ) 1281 \ 1090 l 1290 S (b) Upland Timber Soils (page 25) Yellow-gray silt loam lYellow silt loam Yellow-gray sandy loam Yellow-gray sandy loam on gravel Dune sand Gravelly loam 196.01 38.50 .76 1.48 1.47 .96 125 447 24 639 488 944 938 611 40.59 7.98 .16 .30 .30 .20 1527 (c) Terrace Soils (page 30) Brown silt loam over gravel 1.85 1 184 .38 1564.4 Yellow-gray sandy loam on gravel 2.25 1 440 .47 1560.4 Brown sandy loam on gravel 2.40 1 539 :50 1590.4 Gravelly loam on gravel .28 179 .06 1401 (d) Swamp and Bottom-Land Soils (page 32) Deep peat 38.10 24 382 7.89 1402 Medium peat on clay 1.00 640 .21 1402.2 Medium peat on sand . ! .44 284 .09 1403 Shallow peat on clay .58 371 .12 1410 Peaty loam 2.35 1 504 .49 1450 Black mixed loam 19.72 12 622 4.09 1454 Mixed loam (bottom land) 8.51 5 446 1.76 1482 Beach sand (mixed sand and peat) 7.79 4 988 1.61 (e) Miscellaneous (page 38) Lakes 17.99 11 512 3.72 Total 482.82 309 003 100.00 Lake County 3 ID 15] The soils of Lake county are divided into the following classes: (1) Upland prairie soils, usually rich in organic matter. These were cov- ered originally with prairie grasses, the partially decayed roots of which have been the source of the organic matter. The flat, poorly drained areas contain the highest amounts of organic matter, owing to the more luxuriant growth of grasses there and the better chance for their preservation by the excessive mois- ture in the soil. (2) Upland timber soils, including nearly all upland areas that were for- merly covered with forests. These soils contain much less organic matter than the soils of the prairies because the large roots of dead trees and the surface accumulations of leaves, twigs, and fallen trees were burned by forest fires, or suffered almost complete decay, instead of being incorporated with the soil. (3) Terrace soils, which include bench lands, or second bottom lands, that were formed at the time of the melting of the glacier, when the valleys were flooded and the streams overloaded with coarse sediment. Deposits of gravel were formed which later have been cut thru in part by the streams during their ordinary stages. These benches form soil types that are usually underlain by gravel or sand. (4) Swamp and bottom-land soils, which include the overflow lands or flood plains along the streams, the swamps around some of the lakes, the poorly drained lowlands, and the area of sand beaches deposited by Lake Chicago. Table 1 shows the area of each type of soil in Lake county in square miles and in acres, and its percentage of the total area: It will be noted that the yellow- gray silt loam, or undulating timber land, occupies the larger part of the county. The accompanying map shows the location and boundary lines of every type of soil in the county, even down to areas of a few acres. THE INVOICE AND INCREASE OF FERTILITY IN LAKE COUNTY SOILS Soil Analysis In order to avoid confusion in applying in a practical way the technical information contained in this report, the results are given in the most simplified form. The composition reported for a given soil type is, as a rule, the average of many analyses, which, like most things in nature, show more or less variation ; but for all practical purposes the average is most trustworthy and sufficient. (See Bulletin 123, which reports the general soil survey of the state, together with many hundred individual analyses of soil samples representing twenty-five of the most important and most extensive soil types in the state.) The chemical analysis of the soil gives the invoice of fertility actually pres- ent in the soil strata sampled and analyzed, but, as explained in the Appendix, the rate of liberation is governed by many factors. Also, as there stated, prob- ably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the 4 Soil Report No. 9 [April, poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that the productive power of normal soil in humid sections depends upon the stock of plant food contained in the soil and upon the rate at which it is liberated. The fact may be repeated, too, that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, while seven are secured from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes) in case the amount liberated from the soil is insufficient. But even the leguminous plants (which include the clovers, peas, beans, alfalfa, and vetches), in common with other agricultural plants, secure from the soil alone six elements (phosphorus, potassium, magnesium, calcium, iron, and sulfur) and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Table A in the Appendix shows the requirements of large crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally from natural sources in sufficient abundance, com- pared with the amounts needed by plants, so that they are never known to limit the yield of common farm crops.) In Table 2 are reported the amounts of organic carbon (the best measure of the organic matter) and the total amounts of the five important elements of plant food contained in 2 million pounds of the surface soil of each type, — the plowed soil of an acre about 6% inches deep. In addition, the table shows the amount of limestone present, if any, or the soil acidity as measured by the amount of limestone required to neutralize the acidity existing in the soil. The soil to the depth indicated includes at least as much as is ordinarily turned with the plow, and represents that part with which the farm manure, limestone, phosphate, or other fertilizer applied in soil improvement is incor- porated. It is the soil stratum that must be depended upon in large part to furnish the necessary plant food for the production of crops, as will be seen from the information given in the Appendix. Even a rich subsoil has little or no value if it lies beneath a worn-out surface, for the weak, shallow-rooted plants will be unable to reach the supply of plant food in the subsoil. If, however, the fertility of the surface soil is maintained at a high point, then the plants, with a vigorous start from the rich surface soil, can draw upon the subsurface and subsoil for a greater supply of plant food. By easy computation it will be found that the most common prairie soil of Lake county does not contain more than enough total nitrogen in the plowed soil for the production of maximum crops for fifteen rotations (60 years), while the still more extensive upland timber soil (yellow-gray silt loam) contains only about one-third as much nitrogen as the prairie land, or sufficient for only eighteen 100-bushel crops of corn, grain, and stalks. With respect to phosphorus, the condition differs only in degree, half the soil area of the county containing no more of that element than would be re- Cm l CA&O, ',H I CA GQ , AiLKflO.) AHNMH .>IV f> m ' -4-^1 f n? > - I W A n, Uy RP1 ^ ° ( 1 t— <$=^o | qm5 jg* Lm°\ ■ OJ (M n ■J |i ; i if j 85 il ,, i m I * Hi ill 2 J1HSS I !Uli ^iini «ii, i f -> Q Z 4 LlI d o ^ I liiti ! j I i J Jjf Bill sit- I is 1 1 1 I f 5, 1 Iljjj MAP OF LAKE COUNTY library OF THE n-r-^TY OF ILLINOIS 1915 ] Lake County auired for ten crop rotations if such yields were secured as are suggested in Table A of the Appendix. It will be seen from the same table that in the case of the cereals about three-fourths of the phosphorus taken from the soil is de- posited in the grain, while only one-fourth remains in the straw or stalks. On the other hand, the potassium in the most common soil type is sufficient for 36 centuries if only the grain is sold, or for 560 years even if the total crops should be removed and nothing returned. The corresponding figures are about 2,300 and 540 years for magnesium, and about 7,800 and 200 years for calcium. Thus, when measured by the actual crop requirements for plant food, potassium is no more limited than magnesium and calcium; and as explained in the Ap- pendix, with magnesium, and more especially with calcium, we must also con- sider the fact that loss by leaching is far greater than by cropping. These general statements relating to the total quantities of plant food in the plowed soil of the most prevalent type in the county certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the needs of large crop yields for even one or two generations of people. Table 2. — Fertility in the Soils op Lake County, Illinois Average pounds per acre in two million pounds of surface soil (about 0 to 6% inches) Soil type Soil type | Total Total Total si nitro- phos- potas- 1 gen phorus sium Lime- stone present Soil acidity Upland Prairie Soils 1226 1 Brown silt loam 89 950 7 490 1 430(46 930 12 680 13 300 50 1060 | Brown sandy loam 8 300| 640, 420 25 200 ( 2 680 5 020 40 Upland Timber Soils 1234 Yellow-gray silt loam. . . 32 220 2 720 750 46 300 1 9 210 7 820 40 1035 Yellow silt loam 20 900 1 880 720 58 300 12 380 6 270 30 1064 Yellow-gray sandy loam . 18 000 1 720 800 34 280 5 480 7 220 20 1064.4 Yellow-gray sandy loam on gravel 20 660 1 520 920 34 580 ( 5 080 10 460 40 1281 Dune sand 26 000 1 860 780 23 960 4 920 8 760 12 720 140 1U90 Gravelly loam 33 580 2 760 1 000 30 920 11 960 16 000 Terrace Soils 1527 Brown silt loam over gravel 62 340 5 180 1 340 36 340 7 460 8 900 60 1564.4 Yellow-gray sandy loam on gravel 30 820 2 680 1 120 38 600 7 480 9 540 40 1560.4 Brown sandy loam on gravel 28 280 2 420 780 37 660 7 680 10 680 20 1590.4 Gravelly loam on gravel 37 380 3 240 1 420 | 33 380 8 960 9 160 1 020 Swamp and Bottom-Land Soils 1401 Deep peat (slightly de- composed moss) 445 080 7 990 670 6 120 3 360 2 850 8 380 1401 Deep peat, normal phase 398 040 32 570 1 540 3 900 6 260 24 970 140 1402 Medium peat on clay . . . 206 230 17 380 1 240 16 450 9 140 18 450 50 1402.2 Medium peat on sand . . . 271.560 18 450 1 080 12 420 8 080 18 860 80 1403 Shallow peat on clay. . . 380 800 27 420 1 110 6 410 6 310 28 780 290 1410 Peaty loam 334 170 31 650 2 300 18 540 13 410 40 050 Often 1450 Black mixed loam 164 480 13 640 1 740 35 000 14 140 24 760 16 080 1454 Mixed loam (bottom land) 89 440 8 190 1 490 34 690 45 460 91 180 301 130 1482 Beach sand 5 420 420 660 16 100 9 620 14 320 20 6 Soil Report No. 9 [April, The variation among the different types of soil in Lake county with respect to their content of important plant-food elements is also very marked. Thus the yellow silt loam contains in 2 million pounds of surface soil sufficient total nitrogen for 12 “maximum” crops of corn, sufficient phosphorus for 31 crops, and potassium for 800 such crops ; while the deep peat contains in 1 million pounds of surface soil, nitrogen for 217, phosphorus for 67, and potassium for only 53 corn crops of 100 bushels each. Each of these soil types covers about 8 percent of the county. More than 90 percent of the soils of the county contain no limestone in the surface or subsurface to a depth of 20 inches, altlio the pres- ence of limestone is beneficial for most crops, especially for the valuable biennial and perennial legumes, such as the clovers and alfalfa. With an inexhaustible supply of nitrogen in the air, and with 46,000 pounds of potassium in the most common timber soil, the economic loss in farming such land with some acidity and with only 750 pounds of total phosphorus in the plowed soil can be appreciated only by the man who fully realizes that in less than one generation the crop yields could be doubled by the proper use of lime- stone and phosphorus in rational farm systems, without change of seed or sea- son and with very little more work than is now devoted to the fields. For- tunately, some definite field experiments have already been conducted on this most extensive type of soil in Lake county. Results of Experiments on Antioch Field Table 3 shows in detail thirteen years’ results secured from the Antioch soil experiment field located on the farm of Mr. D. M. White, on the yellow-gray silt loam of the late Wisconsin glaciation. Table 4 is a financial summary of these results. The Antioch field was started in order to learn as quickly as possible what effect would be produced by the addition to this type of soil, of nitrogen, phos- phorus, and potassium, singly and in combination. These elements were all added in commercial form until 1911, after which the use of commercial nitrogen was discontinued and crop residues were substituted in its place. (See report of Urbana field for further explanations, page 9.) Only a small amount of lime was applied at the beginning, in harmony with the teaching which was common at that time; furthermore, Plot 101 proved to be abnormal, so that no conclu- sions can be drawn regarding the effect of lime. In order to ascertain the effect produced by additions of the different elements singly, Plot 102 must be re- garded as the check plot. Three other comparisons are also possible to deter- mine the effect of each element under different conditions. As an average of 40 tests (4 each year for ten years), liberal applications of commercial nitrogen produced a slight decrease in crop values; but as an average of thirteen years each dollar invested in phosphorus paid back $2.54 (Plot 104), while potassium applied in addition to phosphorus (Plot 108) pro- duced no increase, the crops being valued at the lower prices used in the tabular statement. Thus, while the detailed data show great variation, owing both to some irregularity of soil and to some very abnormal seasons, with three almost complete crop failures (1904, 1907, and 1910), yet the general summary strongly confirms the analytical data in showing the need of applying phosphorus and Table 3. — Crop Yields in Soil 1915 ] Lake County 7 !| 33 ' 6.9 31.6 1.3 2.2 22.5 -15.0 -14.2 12.8 -4.2 -.4 26.6 7.2 CO CO CO 00 CO O 7”^ 7 333§§ i -1.3 9.3 .9 -21.8 -11.2 2.S . -3.1 3.9 3.4 7.5 14.5 10.5 3S52S 3 = 33|? 3 1 -10.0 -.3 -3.1 3.4 13.1 1 16.0 25253 5 HH CM 1.2 5.0 3.1 6.5 10.3 4.6 I Fl, fin Ph ill 3 No seed produced: clover plowed Soil Report No. 9 [April, the profit from its use, and the loss in adding potassium. In most cases com- mercial nitrogen damaged the small grains by causing the crop to lodge ; but in those years when a corn yield of 40 bushels or more was secured by the appli- cation of phosphorus either alone or with potassium, then the addition of nitro- gen produced an increase. Table 4. — Value op Crops per Acre in Thirteen Years, Antioch Field Plot Soil treatment applied Total value of thirteen crops Lower prices' Higher prices 2 101 None $135.12 $193.03 171.06 102 119.74 103 Lime, nitrogen 124.70 178.15 104 Lime, phosphorus 202.20 288.85 105 Lime, potassium 138.88 198.40 106 Lime, nitrogen, phosphorus 179.41 256.31 107 Lime, nitrogen, potassium 133.54 190.77 108 Nitrogen, phosphorus, potassium 201.35 287.65 109 Lime, nitrogen, phosphorus, potassium 191.22 273.18 110 Nitrogen, phosphorus, potassium 181.18 258.83 Value of Increase per Acre in Thirteen Years For nitrogen ! For phosphorus For nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassium, nitrogen, and phosphorus over nitrogen and phosphorus . . . $ 4.96 82.46 -22.79 54.71 11.81 $ 7.09 117.79 -32.54 78.16 16.87 'Wheat at 70 cents a bushel, corn at 35 cents, oats at 28 cents, hay at $7 a ton. “Wheat at $1 a bushel, corn at 50 cents, oats at 40 cents, hay at $10 a ton. Plate 1. — Clover in 1913 on Antioch Field Lime Applied and Residues Plowed Under 1915] Lake County 9 From a comparison of the results from the Urbana, Sibley, and Blooming- ton fields (see following pages), we must conclude that better yields are to be secured by providing nitrogen by means of farm manure or legume crops grown in the rotation than by the use of commercial nitrogen, which is evidently too readily available, causing too rapid growth and consequent weakness of straw; and of course the atmosphere is the most economic source of nitrogen where that element is needed for soil improvement in general farming. (See Appendix for detailed discussion of “Permanent Soil Improvement.” Results of Field Experiments at Urbana No soil experiment field has been conducted on the brown silt loam of the late Wisconsin glaciation, but we may well consider the results from long-con- tinued experiments on similar soil in the early Wisconsin glaciation, as at Urbana in Champaign county, at Sibley in Ford county, and at Bloomington in McLean county. (Long-cultivated fields of brown silt loam in the late Wisconsin gla- ciation are sometimes found to contain no more phosphorus or nitrogen than the average in the brown silt loam of the early Wisconsin.) A three-year rotation of corn, oats, and clover was begun on the North Farm at the University of Illinois in 1902, on three fields of typical brown silt loam prairie land which, after twenty years or more of pasturing, had grown corn in 1895, 1896, and 1897 (when careful records were kept of the yields produced), and had then been cropped with clover and grass on one field (Series 100), oats on another (Series 200), and oats, cowpeas, and corn on the third field (Series 300) until 1901. Plate 2. — Clover in 1913 on Antioch Field Lime and Phosphorus Applied 10 Soil Bepobt No. 9 [April, From 1902 to 1910 the three-year rotation (with cowpeas in place of clover in 1902) was followed ; the average yields are recorded in Table 5. A small crop of cowpeas in 1902 and a partial crop of clover in 1904 constituted all the hay harvested during the first rotation, mammoth clover grown in 1903 having lodged so that it was plowed under. (The yields were taken by carefully weighing the clover from small representative areas, but while the differences were thus ascer- tained and properly credited temporarily to the different soil treatments, they must ultimately reappear in subsequent crop yields, and consequently the 1903 clover crop is omitted from Table 5 in computing yields and values. ) The aver- age yields. given represent one-third of the two small crops. From 1902 to 1907 legume cover crops (Le), such as cowpeas and clover, were seeded in the corn at the last cultivation on Plots 2, 4, 6, and 8, but the growth was small and the effect, if any,' was to decrease the returns from the regular crops. Since 1907 crop residues (R) have been returned to those plots. These consist of the stalks of corn, the straw of small grains, and all legumes except alfalfa hay and the seed of clover and soybeans. On Plots 3, 5, 7, and 9, manure (M) was applied for corn at the rate of 0 tons per acre during the second rotation, and subsequently as many tons of manure have been applied as there were tons of air-dry produce harvested from the corresponding plots. Lime (L) was applied on Plots 4 to 10 at the rate per acre of 250 pounds of air-slaked lime in 1902 and 600 pounds of limestone in 1903. Subsequently 2 tons per acre of limestone was applied to these plots on Series 100 in 1911, on Series 200 in 1912, on Series 300 in 1913, and on Series 400 in 1914 ; also 2^2 tons per acre on Series 500 in 1911, two more fields having been brought into rotation, as explained below. Phosphorus (P) has been applied on Plots 6 to 9 at the rate of 25 pounds per acre per annum in 200 pounds of steamed bone meal ; but beginning with 1908, one half of each phosphorus plot has received 600 pounds of rock phosphate in place of the 200 pounds of bone meal, the usual practice being to apply and plow under at one time all phosphorus and potassium required for the rotation. Potassium (K=kalium) has been applied on Plots 8 and 9 at the yearly rate of 42 pounds per acre in 100 pounds of potassium sulfate, regularly in con- nection with the bone meal and rock phosphate. On Plot 10 about five times as much manure and phosphorus are applied as on the other plots, but this “extra heavy” treatment was not begun until 1906, only the usual lime, phosphorus, and potassium having been applied in previous years. The purpose in making these heavy applications is to try to determine the climatic possibilities in crop yields by removing the limitations of inadequate fertility. Series 400 and 500 were cropped in corn and oats from 1902 to 1910, but the corresponding plots were treated the same as in the three-year rotation. Beginning with 1911', the five series have been used for a combination rotation, wheat, corn, oats, and clover being rotated for five years on four fields, while alfalfa occupies the fifth field, which is then to be brought under the four-crop system to make place for alfalfa on one of the other fields for another five-year period, and so on. (See Table 6.) 1916 ] Lake County 2 3 <4 V ca ■< os J 5 o § ” g 3 If ii S3 S m a z ^ £ I S wffl of 3 >ps Higher prices $64.02 62.41 78.43 67.53 85.85 90.10 107.16 84.65 105.89 100.27 1 Value er< Lower prices $44.81 43.69 54.90 47.27 60.09 63.07 75.01 59.26 74.12 70.19 £ g? O Ofl O O CO CO Cl ^ co os to 0 os CM* rH* CM* CM* M* (2.64) 4.17 (1.99) 3.90 3.79 Oats, bu. 00 rH CQ t> LO I LO -rjj LO CO CO 0 cb cb to rfi lo cb co* hh HHHtHtTjHHHjLOLOLOLOLO Corn, bu. 49.4 51.5 69.3 58.1 74.9 ~83.8" 86.6 86.7 90.9 81.3 Soil treat- ment 0 R M RL.... ML. . . . RLP . . . MLP. . . RLPK MLPK MxLPx <35 lO b- 05 1 O o 5 OS S CD CO CD CO O O0 CD GO CO CQ tJH 00 OS* ^ IQ IO IO LO s cd r> os os © rH rH CO M* t>- t- fr- to CO LO LO CO 00 i 06 © ci ^ CDOOSOO I GQ 00 CO rH > CO* CO* LO* © ) OS OS OS OS P Pn P d Pm ^ Pd I rH rH os CO © LO W t- I CO* - OS CO OS CO CO : U O * 01 A u ^ v ;i hJ5T. •£ O 0 ... <15 II o Pu -g 'I ' ' ; 00 H LO IO 6 00 © © cb 0 00 OS OS 00 LO CO N 00 OS O § a sis 3S 12 Soil Report No. 9 [ April, Table 6.— Yields per Acre, Four-year Averages, 1911-1914: Urbana Field Brown Silt Loam Prairie; Early Wisconsin Glaciation Serial plot No. Soil treat- ment Wheat, bu. Corn, bu. Oats, bu. Soybeans-3, tons (bu.) Clover-1, *| tons (bu.) Alfalfa, tons Value of 5 crops Lower prices Higher prices ' 1“ 0. .77777. 18.3 50.8 39.8 L60 1.70 L70~ ~$65W $92.87 2 R 19.7 53.8 40.6 (20.1) ( -74) 1.27 64.72 92.47 3 M 20.3 59.3 48.8 1.60 1.43 1.13 67.44 96.35 4 RL 22.3 55.7 42,8 (19.0) (1.03) 1.19 67.20 96.00 5 ML 24.9 58.6 51.6 1.66 1.67 76.19 108.S4 6~ RLP .... 37.4 62.2 58.7 (2L0) (2.48) _ —fUjST 98.58 140.83" 7 MLP 36.6 63.8 60.9 1.88 2.90 2.63 98.36 140.51 8 RLPK. . . 36.1 58.9 59.1 (22.2) (1.41) 2.58 94.61 135.16 9 MLPK . . 35.3 59.6 65.1 2.09 2.72 2.66 98.15 140.22 10 MxLPx. . 43.5 | 55.7 67.2 2.14 2.94 I 2.84 105.02 150.03 From 1911 'to 1914 soybeans were substituted three years because of clover failure, and three-fourths of the soybeans and one-fourth of the clover are used to compute values. Alfalfa from the 1911 seeding so nearly failed that after cutting one crop in 1912, the field was plowed and reseeded. The average yield reported for alfalfa in Table 6 is one-fourth of the combined crops of 1912, 1913, and 1914. Plate 3. — Clover in 1913 on Urbana Field Farm Manure Applied Yield, 1.43 Tons per Acre 191S\ Lake County 13 The “higher prices” allowed for produce are $1 a bushel for wheat and soybeans, 50 cents for corn, 40 cents for oats, $10 for clover seed, and $10 a ton for hay; while the “lower prices” are 70 percent of these values, or 70 cents for wheat and soybeans, 35 cents for corn, 28 cents for oats, $7 for clover seed, and $7 a ton for hay. The double set of values is used to emphasize the fact that a given practice may or may not be profitable, depending upon the prices of farm produce. The lower prices are conservative, and unless otherwise stated, they are the values regularly used in the discussion of results. It should be understood that the increase produced by manures and fertilizers requires in- creased expense for binding twine, shocking, stacking, baling, threshing, haul- ing, storing, and marketing. Measured by the average Illinois prices for the past ten years, these lower values are high enough for farm crops standing in the field ready for the harvest. The cost of limestone delivered at the farmers’ railroad station in carload lots averages about $1.25 per ton. Steamed bone meal in carloads costs from $25 to $30 per ton. Fine-ground raw rock phosphate containing from 260 to 280 pounds of phosphorus, or as much as the bone meal contains, ton for ton, but in less readily available form, usually costs the farmer from $6.50 to $7.50 per ton in carloads. (Acid phosphate carrying half as much phosphorus, but in soluble form, commonly costs from $15 to $17 per ton delivered in carload lots Plate 4. — Clover in 1913 on Urbana Field Farm Manure, Limestone, and Phosphorus Applied Yield, 2.90 Tons per Acre 14 Soil Report No. 9 [April, in central Illinois.) Under normal conditions potassium costs about 6 cents a pound, or $2.50 per acre per annum for the amount applied in these experi- ments, the same as the cost of 200 pounds of steamed bone meal at $25 per ton. To these cash investments must be added the expense of hauling and spread- ing the materials. This will vary with the distance from the farm to the rail- road station, with the character of roads, and with the farm force and the imme- diate requirements of other lines of farm work. It is the part of wisdom to order such materials in advance to be shipped when specified, so that they may be re- ceived and applied when other farm work is not too pressing and, if possible, when the roads are likely to be in good condition. The practice of seeding legume cover crops in the cornfield at the last culti- vation where oats are to follow the next year has not been found profitable, as a rule, on good corn-belt soil ; but the returning of the crop residues to the land may maintain the nitrogen and organic matter equally as well as the hauling and spreading of farm manure, — and this makes possible permanent systems of farm- ing on grain farms as well as on live-stock farms, provided, of course, that other essentials are supplied. (Clover with oats or wheat, as a cover crop to be plowed under for corn, often gives good results.) At the lower prices for produce, manure (6 tons per acre) was worth $1.05 a ton as an average for the first three years it was applied (1905 to 1907). The next rotation the average application of 10.21 tons per acre on Plot 3 was worth $10.09, or 99 cents a ton. The last four years, 1911 to 1914, the average amount applied (once for the rotation) on Plot 3 was 11.35 tons per acre, worth $6.42, or 57 cents a ton, as measured by its effect on the wheat, corn, oats, soybeans, and clover. Thus, as an average of the ten years’ results, the farm manure ap- plied to Plot 3 has been worth 84 cents a ton on common corn-belt prairie soil, with a good crop rotation including legumes. During the last rotation period moisture has been the limiting factor to such an extent as probably to lessen the effect of the manure. Aside from the crop residues and manure, each addition affords a duplicate test as to its effect. Thus the effect of limestone is ascertained by comparing Plots 4 and 5, not with Plot 1, but with Plots 2 and 3 ; and the effect of phosphorus is ascertained by comparing Plots 6 and 7 with Plots 4 and 5, respectively. As a general average the plots receiving limestone have produced $1.22 an acre a year more than those without limestone, and this corresponds to more than $6 a ton for all of the limestone applied; but the amounts used before 1911 were so small and the results vary so greatly with the different plots, crops, and seasons that final conclusions cannot be drawn until further data are secured, the first 2-ton applications having been completed only for 1914. However, all comparisons by rotation periods show some increase for limestone, varying from 82 cents on three acres (Plot 4) during the first rotation, to $8.75 on five acres (Plot 5) as an average of the last four years; and the need of limestone for best results and highest profits seems well established. As an average of duplicate trials (Plots 6 and 7), phosphorus in bone meal produced increases valued at $1.92 per acre per annum for the first three years and at $4.67 for the next three; and the corresponding subsequent average in- creases from bone meal and raw phosphate (one-half plot of each) were $5.12 for the third rotation and $5.36 for the last four years, 1911 to 1914. The annual Lake County 15 1915 ] expense per acre for phosphorus is $2.80 in bone meal at $28 a ton, or $2.10 for rock phosphate at $7 a ton. Potassium, applied at an estimated cost of $2.50 an acre a year, seemed to produce slight increases, as an average, during the first and second rotations; but subsequently those increases have been slightly more than lost in reduced average yields, the net result to date being an average loss of $2.53 per acre per annum, including the cost of the potassium. Thus phosphorus nearly paid its cost during the first rotation, and has sub- sequently paid its annual cost and about 100 percent net profit ; while potassium, as a general average, has produced no effect, and money spent for its applica- tion has been lost. These field results are in harmony with what might well be expected on land naturally containing in the plowed soil of an acre only about 1,200 pounds of phosphorus and more than 36,000 pounds of potassium. The total value of five average crops harvested from the untreated land dur- ing the last four years is $65. Where limestone and phosphorus have been used together with organic manures (either crop residues or farm manure), the cor- responding value exceeds $98. Thus 200 acres of the properly treated land would produce as much in crops and in value as 300 acres of the untreated land. The excessive applications- on Plot 10 have usually produced rank growth of straw and stalk with the result that oats have often lodged badly and corn has frequently suffered from drouth and eared poorly. Wheat, however, has as an average yielded best on this plot. The largest yield of corn on Plot 10 was 118 bushels per acre in 1907. Results of Experiments of Sibley Field Table 7 gives the results obtained during twelve years from the Sibley soil experiment field located in Ford county on the typical brown silt loam prairie of the Illinois corn belt. Previous to 1902 this land had been cropped with corn and oats for many years under a system of tenant farming, and the soil had become somewhat defi- cient in active organic matter. While phosphorus was the limiting element of plant food, the supply of nitrogen becoming available annually was but little in excess of the phosphorus, as is well shown by the corn yields for 1903, when the addition of phosphorus produced an increase of 8 bushels, nitrogen produced no increase, but nitrogen and phosphorus together increased the yield by 15 bushels. After six years of additional cropping, however, nitrogen appeared to be- come the most limiting element, the increase in the corn in 1907 being 9 bushels from nitrogen and only 5 bushels from phosphorus, while both together pro- duced an increase of 33 bushels. By comparing the corn yields for the four years 1902, 1903, 1906, and 1907, it will be seen that the untreated land appar- ently grew less productive, whereas, on land receiving both phosphorus and nitrogen, the yield appreciably increased, so that in 1907, when the untreated rotated land produced only 34 bushels of corn per acre, a yield of 72 bushels (more than twice as much) was produced where lime, nitrogen, and phosphorus had been applied, altho the two plots produced exactly the same yield (57.3 bushels) in 1902. 16 Soil Report No. 9 [April, Even in the unfavorable season of 1910 the yield of the highest producing plot exceeded the yield of the same plot in 1902, while the untreated land pro- duced less than half as much as it produced in 1902. The prolonged drouth of 1911 resulted in almost a failure of the corn crop, but nevertheless the effect of soil treatment was seen. Phosphorus appeared to be the first limiting element again in 1909, 1910, and 1911; while the lodging of oats, especially on the nitro- gen plots, in the exceptionally favorable season of 1912, produced very irregular results. In 1913, wheat averaged 6.6 bushels without nitrogen or phosphorus Table 7. — Crop Yields in Soil Experiments, Sibley Field Brown silt loam prairie ; 1 early Wisconsin glaciation Corn Corn Oats Wheat 1902,19031904 1905 ill Corn 1906 Corn 1907 Oats j Wheat) Corn [ 1908 1909 1910| Corn 1911 Oats 1912 Wheat 1913 Plot Soil treatment applied Bushels per acre 101 None 57.3 50.4 74.4 29.5 36.7 33.9 25.9 25.3 26.6 20.71 84.4 5.5 102 Lime GO.O 54.0 74.7 31.7 39.2 38.9 24.7 28.8 34.0 22.2 85.6 6.8 T03" Lime, nitro 60.0 54.3 77.5 32JT 4L7 18J 36.3 19.0 2976 “22 A \~253 18.3 104 Lime, phos 61.3 62.3 92.5 36.3 44.8 43.5 25.6 32.2 52.0 31.6 92.3 10.7 105 Lime, potas 56.0 49.9 74.4 30.2 37.5 34.9 22.2 23.2 34.2 21.6 83.1 7.5 10G Lime, nitro., phos.. . 57.3 69.1 88.4 45 2 68.5 72^3 45.6 33.3 ~5iL6 "3^3 42.2 24.7 107 Lime, nitro., potas.. 53.3 51.4 75.9 37.7 39.7 51.1 42.2 25.8 46.2 20.1 55.6 19.2 108 Lime, phos., potas.. . 58.7 60.9 80.0 39.8 41.5 39.8 27.2 28.5 43.0 31.8 79.7 11.8 109 Lime, nitro., phos., potas 58.7 65.9 82.5 48.0 69.5 80.1 52.8 35.0 58.0 35.7 57.2 24.5 110 Nitro., phos., potas.. 60.0 60.1 I 85.0 48.5 63.3 72.3 44.1 30.8 64.4 31.5 54.1 18.0 Increase: Bushels per Acre For nitrogen .0 .3 2.8 1.1 2.5 1 9.2 11.6 -9.8 -5.01 .2 -60.3 11.5 For phosphorus 1.3 8.3 17.8 4.6 5.6 4.6 .9 3.4 18.0 1 9.4 0.7 3.9 For potassium -4.0 -4.1 -.3 -1.5 -1.7, -4.0 ! -2.5 -5.6 .2, -.6 -2.5 .7 For nitro., phos. over phos -4.0 6.8 -4.1 8.9 1 23.7, 28.8 20.0 1.1 1 3.6 3.7 -50.1 14.0 For phos., nitro. over nitro -2.7 14.8 10.9 12.4 1 24.8 24.2 1 9.3 14.3 1 26.6 12.9 16.9 6.4 For potas., nitro., phos. over nitro., phos 1.4' -3.2 -5.9 2.8 1.0 7.8' 7.2 1.7 1 2.4 .4 15.0 -.2 Value of Crops per Acre in Twelve Years Plot Soil treatment applied Total \ twelve Lower prices 'alue of , crops Higher prices 101 $172.89 186.51 $246.98 266.45 102 103 Lime, nitrogen 177.44 253.49 104 Lime, phosphorus 217.78 311.11 105 Lime, potassium 167.32 239.03 106 Lime, nitrogen, phosphorus 246.91 352.73 107 Lime, nitrogen, potassium 198.16 283.08 108 Lime, phosphorus, potassium 204.90 292.71 "loa Lime, nitrogen, phosphorus, potassium 257.91 368.45 110 Nitrogen, phosphorus, potassium 242.47 346.38 Value of Increase per Acre in Twelve Years For nitrogen $ 9.07 $12.96 For phosphorus For nitrogen and phosphorus over phosphorus 31.27 29.13 44.66 41.62 For phosphorus and nitrogen over nitrogen 69.47 99.24 Fnr 'nni.n.Rsi'ii.nm. nifrnorpn ntul TVhnsTVhnrns nvpr nifrnorpn anrl TVhnsnhnrns 11.00 15.72 1915 ] Lake County 17 (Plots 101, 102, 105) and 22.4 bushels where both nitrogen and phosphorus were added (Plots 106, 109, 110). In the lower part of Table 7 are shown the total values per acre of the twelve crops from each of the ten different plots, the amounts varying from $167.32 to $257.91, with corn valued at 35 cents a bushel, oats at 28 cents, and wheat at 70 cents. Phosphorus without nitrogen has produced $31.27 in addition to the increase by lime, but with nitrogen it has produced $69.47 above the crop values where only lime and nitrogen have been used. The results show that in 26 cases out of 48 the addition of potassium has decreased the crop yields. Even when applied in addition to phosphorus, and with no effort to liberate potassium from the soil by adding organic matter, potassium has produced no increase in crop values as an average of the results from Plots 108 and 109. By comparing Plots 101 and 102, and also 109 and 110, it is seen that lime has produced an average increase of $14.53, or $1.21 an acre a year. This in- crease on these plots is practically the same as at Urbana, and it suggests that the time is here when limestone must be applied to some of these brown silt loam soils. While nitrogen, on the whole, has produced an appreciable increase, espe- cially on those plots to which phosphorus has also been added, it has cost, in com- mercial form, so much above the value of the increase produced that the only conclusion to be drawn, if we are to utilize this fact to advantage, is that the nitrogen must be secured from the air. Results of Experiments on Bloomington Field Space is taken to insert Tables 8 and 9, giving all results thus far obtained from the Bloomington soil experiment field, which is also located on the brown silt loam prairie soil of the Illinois corn belt. The general results of the thirteen years’ work on the Bloomington field tell much the same story as those from the Sibley field. The rotations have differed since 1905 by the use of clover and the discontinuing of the use of commercial nitrogen on the Bloomington field, — in consequence of which phosphorus without commercial nitrogen, on the Bloomington field, has produced an even larger in- crease ($99.85) than has been produced by phosphorus and nitrogen over nitro- gen on the Sibley field ($69.47) . It should be stated that a draw runs near Plot 110 on the Bloomington field, that the crops on that plot are sometimes damaged by overflow or imperfect drainage, and that Plot 101, occupies the lowest ground on the opposite side of the field. In part because of these irregularities and in part because only one small application has been made, no conclusions can be drawn in regard to lime. Otherwise all results reported in Table 8 are considered reliable. They not only furnish much information in themselves, but they also offer instructive com- parison with the Sibley field. Wherever nitrogen has been provided, either by direct application or by the use of legume crops, the addition of the element phosphorus has produced very marked increases, the average yearly increase for the Bloomington field being worth $7.02 an acre. This is $4.52 above the cost of the phosphorus in 200 pounds of steamed bone meal, the form in which it is applied on the Sibley and the Bloomington fields. On the other hand, the use of phosphorus without nitrogen Table 8.- Soil Report No . 9 Oats 1914 Bushels or tons per acre QO 50 [OO © °0 |< ai o © io •£$ i oq ^ CO 00 ji 62.3 34.5 63.1 54.4 44.8 Corn | Corn 1912 j 1913 i ^ o o4 © CO CO 37.5 44.1 32.1 50.4 34.5 49.4 49.0 33.8 55.2 47.9 62.5 74.5 57.8 86.1 58.9 79.2 83.4 78.3 Wheat 1911 22.5 22.5 25.6 57.6 21.7 60.2 27.3 54.0 60.4 61.0 Clover 2 1910 1.56 1.09 QOWN ’ iH 5*5 ® 05 <3§ 46.4 53.6 49.4 63.8 45.3 72.5 51.1 59.5 64.2 55.3 fl oo fH O O 05 O rH 40.3 35.3 36.9 47.5 36.2 45.8 31.0 57.2 58.1 51.4 Corn 1907| 60.8 I 63.1 64.3 82.1 64.1 78.9 64.3 81.4 88.4 78.0 Clover 1906 05 oo CO io .46 1.65 .51 V s 3 CC Wheat 1905 30.8 | 28.8 30.5 39.2 33.2 50.9 29.5 37.8 51.9 51.1 Oats 1904 54.8 1 60.8 oo t>- iq 05 CQ to 85.3 66.4 70.3 90.5 71.4 Corn 1903 63.9 60.3 in © ci CO CD IO 10 77.6 58.9 74.8 80.9 73.1 Corn 1902 30.8 i 37.0 35.1 41.7 37.7 43.9 40.4 50.1 52.7 52.3 Brown silt loam prairie; early Wisconsin glaciation Soil treatment applied None Lime Lime, crop residues 1 Lime, phosphorus Lime, potassium Lime, residues, 1 phosphorus Lime, residues, 1 potassium Lime, phosphorus, potassium Lime, residues, 1 phosphorus, potassium Residues, phosphorus, potassium Plot 101 102 CO T* ID o o o 109 110 7.5 14.1 2.1 6.3 12.9 - 1.4 © CO 05 CO CO t''- - 4.2 10.2 - 8.3 8.7 23.1 - 8.3 1.6 12.2 .9 - 1.7 8.9 12.3 ' 1.2 19.0 1.0 - 3.2 14.6 9.5 -.12 1.07 -.07 - 1.65 -.46 .00 10.4 4.4 11.7 20.4 1 1.0 9.0 11.9 1.7 12.6 15.5 5.2 -.8 12.7 - 3.9 4.6 18.1 3.3 ^■222 [April, “The figures in parenthses mean bushels of seed; the others, tons of hay. “Clover smothered by previous wheat crop. 1015 ] Lake County 19 Table 9. — Value op Crops per Acre in Thirteen Years, Bloomington Field Plot Soil treatment applied Total value of thirteen crops Lower prices Higher prices 101 102 “$186.83 186.76 $266.90 266.80 103 104 105 193.83 276.90 Lime, phosphorus Lime, potassium 286.61 190.53 409.45 272.19 106 Lime, residues, phosphorus 285.03 407.19 107 Lime, residues, potassium 191.10 273.00 108 Lime, phosphorus, potassium 294.91 421.31 109 Lime, residues, phosphorus, potassium 284.47 406.39 110 Residues, phosphorus, potassium 259.10 370.15 Value of Increase per Acre in Thirteen Years For residues For phosphorus 1 $ 7.07 99.85 $ 10.10 142.65 For residues and phosphorus over phosphorus -1.58 -2.26 For phosphorus and residues over residues 91.20 130.29 For potassium, residues, and phosphorus over residues and phosphorus. . . . -.56 -.80 will not maintain the fertility of the soil (see Plots 104 and 106, Sibley field). As the only practical and profitable method of supplying nitrogen, a liberal use of clover or other legumes is suggested, the legume to be plowed under either directly or as manure, preferably in connection with the phosphorus applied, especially if raw rock phosphate is used. Prom the soil of the best treated plots on the Bloomington field, 180 pounds per acre of phosphorus, as an average, has been removed in the thirteen crops. This is equal to 15 percent of the total phosphorus contained in the surface soil of an acre of the untreated land. In other words, if such crops could be grown Plate 5. — Corn in 1912 on Bloomington Field On Left, Residues, Lime, and Potassium: Yield, 58.9 Bushels On Right, Residues, Lime, and Phosphorus: Yield, 86.1 Bushels 20 Soil Report No. 9 [April, for eighty years, they would require as much phosphorus as the total supply in the ordinary plowed soil. The results plainly show, however, that without the addition of phosphorus such crops cannot be grown year after year. Where no phosphorus has been applied, the crops have removed only 120 pounds of phosphorus in the thirteen years, which is equivalent to only 10 percent of the total amount (1,200 pounds) present in the surface soil at the beginning of the experiment in 1902. The total phosphorus applied from 1902 to 1914, as an average of all plots where it has been used, has amounted to 325 pounds per acre and has cost $32.50. This has paid back $97.20, or 300 percent on the invest- ment ; whereas potassium, used in the same number of tests and at the same cost, has paid back only $2.20 per acre in the thirteen years, or less than 7 percent of its cost. Are not these results to be expected from the composition of such soil and the requirements of crops? (See Table 2, page 5, and also Table A in the Appendix.) Nitrogen was applied to this field, in commercial form only, from 1902 to 1905; but clover was grown in 1906 and 1910, and a cover crop of cowpeas after the clover in 1906. The cowpeas were plowed under on all plots, and the 1910 102 103 104 105 106 107 108 109 0 R P K RP RK PK RPK $186.76 $193.83 $286.61 $190.53 $285.03 $191.10 $294.91 $284.47 Plate 6. — Crop Values for Thirteen Years, Bloomington Experiment Field (R=residues; P— phosphorus; K=potassium, or kalium) 1915 ] Lake County 21 clover (except the seed) was plowed under on five plots (103, 106, 107, 109, and 110). Straw and corn stalks have also been returned to these plots in recent years. The effect of returning these residues to the soil has been appreciable since 1910 (an average increase on Plots 106 and 109 of 4.5 bushels of wheat, 5.4 bushels of corn, and 4.3 bushels of oats) and probably will be more marked on subse- quent crops. Indeed, the large crops of corn, oats, and wheat grown on Plots 104 and 108 during the thirteen years have drawn their nitrogen very largely from the natural supply in the organic matter of the soil. The roots and stubble of clover contain no more nitrogen than the entire plant !, from the soil alone, but they decay rapidly in contact with the soil a v .>! [M. bably hasten the decomposition of the soil humus and the consequent libera tm:i f the soil nitro- gen. But of course there is a limit to the reserve stock of humus and nitrogen remaining in the soil, and the future years will undoubtedly witness a gradually increasing difference between Plots 104 and 106, and between Plots 108 and 109, in the yields of grain crops. Plate 6 shows graphically the relative values of the thirteen crops for the eight comparable plots, Nos. 102 to 109. The cost of the phosphorus is indicated Table 10. — Fertility in the Soils op Lake County, Illinois Average pounds per acre in 4 million pounds of subsurface (about 6% to 20 inches) Soil Total Total Total Total Total Total Lime- Soil type Soil type organic nitro- phos- potas- magne- cal- stone acid- No. carbon gen phorus sium sium cium present ity Upland Prairie Soils | Brown silt loam 91 050 7 940 1 1 960 101 020] 29 810| 19 310 1 110 Brown sandy loam 4 280 440 1 1 000 53 720 7 200 | 12 080 | 40 Upland Timber Soils 1234 Yellow-gray silt loam. . . 26 090 2 630 1 300 106 140 31 660 14 190 310 1035 Yellow silt loam 23 980 2 720 1 620 136 020 40 600 13 460 60 1064 Yellow-gray sandy loam. 18 960 2 040 1 840 71 040 19 920 17 560 160 1064.4 Yellow-gray sandy loam on gravel 10 000 680 1 000 69 640 13 920 20 520 40 1281 Dune sand 18 520 720 1 160 53 840 14 280 18 040 80 1090 Gravelly loam 16 200 1 760 1 600 66 560 52 600 75 920 255 400 Terrace Soils 1527 Brown silt loam over gravel 55 560 4 760 1 680 78 440 16 920 14 880 200 1564.4 Yellow-gray sandy loam on gravel 30 320 2 400 2 080 86 880 24 880 15 160 160 1560.4 Brown sandy loam on gravel 21 080 2 200 1 200 82 440 28 160 36 240 72 520 1590.4 Gravelly loam on gravel. 32 240 2 840 2 360 77 880 21 280 19 200 2 720 Swamp and Bottom-Land Soils 1401 Deep peat (slightly de- composed moss) 988 560 32 700 1 000 3 820 7 640 18 080 1 940 1401 Deep peat 535 240 66 050 2 410 8 180 11 880 53 010 460 1402 Medium peat on clay 295 140 24 820 2 140 33 480 18 500 38 660 3 860 1402.2 Medium peat on sand 388 940 25 020 1 340 15 200 15 400 35 760 8 540 1403 Shallow peat on clay. . . 181 560 14 680 2 160 86 360 80 880 151 040 440 800 1410 Peaty loam 40 620 3 760 1 300 52 460 47 720 79 200 264 300 1450 Black mixed loam 115 760 9 840 2 600 78 400 24 920 33 560 4 400 1454 Mixed loam (bottom land) 117 340 10 140 3 320 72 840 94 240 191 800 Often 1482 Beach sand 6 080 240 600 32 280 23 080 36 400 25 760 Soil Report No. 9 [April, 22 by that part of the diagram above the short crossbars. It should be kept in mind that no value is assigned to clover plowed under except as it reappears in the increase of subsequent crops. Plots 106 and 109 are heavily handicapped because of the clover failure on those plots in 1906 and the poor yield of clover seed in 1910, whereas Plots 104 and 108 produced a fair crop in 1906 and a very large crop in 1910. Plot 106, which receives the most practical treatment for permanent agriculture (RLP), has produced a total value in thirteen years only $1.58 below that from Plot 104 (LP). (See also table on last page of cover.) The Subsurface and Subsoil In Tables 10 and 11 are recorded the amounts of plant food in the subsur- face and the subsoil strata of the Lake county soils, but it should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important information contained in these tables is that the subsoils are usually rich in limestone. This fact probably accounts for the moderate success with alfalfa on some Lake county farms, even where limestone has not been applied. If alfalfa is given a good start with manure or by a favorable season, until the roots reach the limestone subsoil, subsequent addition of lime- stone to the plowed soil may not be of much importance. Table 11. — Fertility in the Soils op Lake County, Illinois Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil typo No. Soil type Total organic carbon Total nitro- gen Total 1 Total phos- I potas- phorus sium Total magne- sium Total cal- cium Lime- stone present Soil acid- ity Upland Prairie Soils 1226 Brown silt loam . . . . . 1 33 940 3 350 1 2 480 1 158 810 1 167 400 1 257 290 | 998 570 1 1060 Brown sandy loam. . . 1 6 420 | 660 1 1 500 | 80 580 | 10 800| 18 120 60 Upland Timber Soils 1234 Yellow-gray silt loam 27 080 2 970 2 470 157 500 165 470 261 330 1 066 470 1035 Yellow silt loam 22 380 14 700 2 460 178 710 198 000 263 940 1 179 780 1064.4 Yellow-gray sandy loam on gravel. . . . 23 100 1 680 2 340 119 880 45 060 36 000 60 1281 Dune sand 27 780 1 080 1 740 80 760 21 420 27 060 120 1090 Gravelly loam 24 300 2 640 2 400 99 840 78 900 113 880 383 100 Terrace Soils 1527 1560.4 Brown silt loam over gravel Brown sandy loam on gravel 29 040 12 960 2 760 1 380 1 2 220 2 520 124 440 108 360 42 180 176 880 34 500 278 340 32 220 1 232 460 Swamp and Bottom-Land Soils 1401 Deep peat (slightly de- composed moss) . . 1 443 030 48 870 1 170 6 060 9 900 30 600 2 310 1401 Deep peat 1 269 080 99 070 3 620 12 270 17 820 79 520 690 1402 Medium peat on clay. 99 180 6 840 2 760 165 780 200 640 323 040 1 258 860 1402.2 Medium peat on sand 55 980 3 000 1 860 34 860 91 620 153 840 478 020 1403 Shallow peat on clay. 58 560 3 360 2 280 127 260 209 400 589 860 1 980 120 1410 Peaty loam 19 410 1 260 1 350 85 050 111 030 183 510 744 390 1450 Black mixed loam. . . . 43 620 3 420 1 980 122 880 57 060 74 760 183 840 1454 Mixed loam (bottom land) 72 480 5 730 4 380 112 470 140 400 349 710 Often 1482 Beach sand 9 120 360 900 48 420 34 620 | 54 600 38 640 1915 ] Lake County 23 INDIVIDUAL SOIL TYPES (a) Upland Prairie Soils The upland prairie soils of Lake county cover 140.38 square miles, or 29.08 percent of the entire area of the county. They are usually quite dark in color, owing to their large organic-matter content. They occupy the less rolling and comparatively level land. Brown Silt Loam (1026 and 1226) Brown silt loam is a very important and somewhat extensive type in this county, covering an area of 137.50 square miles, or 28.48 percent of the entire area of the county. It occupies much of the less rolling land, a considerable pro- portion of which needs artificial drainage. The presence of kettle-holes in some places makes complete drainage rather difficult ; and small ponds are frequently found. Many local areas of yellow-gray silt loam, sandy loam, and peat, too small to show on the map, are also interspersed. The surface soil, 0 to 6% inches, is a brown silt loam, varying from a yel- lowish brown on the more rolling areas to a dark brown or black on the more nearly level and poorly drained tracts. In physical composition it varies to some extent, but normally contains from 50 to 70 percent of the different grades of silt. The clay content, as well as the organic-matter content, increases as the type approaches the black mixed loam (1450) of the swampy areas. On account of the complex character of the type, the amount of organic matter also is quite variable, ranging from 5.5 to 9.9 percent, but it averages about 7.6 percent, or 76 tons per acre. Where this type passes into the yellow-gray silt loam, the con- tent of organic matter becomes much lower and the type much more variable. The slightly higher points, perhaps not more than a fraction of an acre in ex- tent, may be decidedly gray or yellow, while the lower adjoining parts may be quite dark, thus giving an extremely variable phase of brown silt loam impos- sible to indicate on the soil map. The subsurface is represented by a stratum varying from 6 to 15 inches in thickness. . This variation is due to changing topography and the effect of ero- sion, the stratum becoming thinner on the more rolling areas. Less organic mat- ter has accumulated on the more rolling areas than on the more nearly level tracts, and to a less depth. In physical composition the subsurface varies the same as the surface soil, but it normally contains a slightly larger amount of clay and a smaller amount of organic matter. The organic matter varies from 2.7 to 4.2 percent, with an average of 3.8 percent, or 38 tons per acre, or half as much as is in the surface soil. In color the subsurface varies from a dark brown or almost black to a light yellowish brown ; it becomes lighter with depth, passing into the subsoil at from 12 to 22 inches. The natural subsoil begins 12 to 22 inches beneath the surface and extends to an indefinite depth but is sampled to 40 inches. It varies from a yellow to a drabbish yellow clayey material sometimes composed of boulder clay, or drift. In some of the flat areas where material has washed in from the higher sur- rounding parts, the subsoil to a depth of 40 inches does not reach the boulder 24 Soil Report No. 9 [April, clay. In many cases the stratum of gravel at 16 to 20 inches interferes with the collecting of samples. Where properly drained, brown silt loam requires only the addition of phos- phorus, limestone, and organic manures for the improvement and permanent maintenance of its productive power. As an average, phosphorus is present in the plowed soil of an acre to the extent of 1,400 pounds, compared with about 7,500 pounds of nitrogen and 47,000 pounds of potassium, altho the lighter phase, as where the type is much worn, contains as low as 1,200 pounds of phos- phorus and 5,000 of nitrogen. No long-continued field experiments have been conducted by the University on this type of soil in the late Wisconsin glaciation, but the results already reported from the fields at Urbana, Sibley, and Blooming- ton (pages 9, 15, and 17), considered together with the composition of the soil, leave no doubt as to the wisdom of adding phosphorus to this soil and of the foolishness of spending money for potassium. This type contains no limestone to a depth of 20 to 30 inches, and liberal use of this material should prove beneficial for clover and alfalfa, even tho the lower subsoil usually contains abundance of limestone. Farm manures, crop residues, or legume crops plowed under are needed, not only to provide nitrogen, but also to give activity to the soil for the liberation of plant food and to main- tain good tilth, or good physical condition. Brown Sandy Loam (1060 and 1260) Brown sandy loam occupies only a small area in the county, amounting to 2.88 square miles, 1,844 acres, or .6 percent of the entire area. The surface soil, 0 to 6% inches, consists of a brown sandy loam varying from a light or yellowish brown to a dark brown or even black color. The areas in the western part of the country are of the lighter colored phase, while those in the eastern part, particularly north of Waukegan, partake somewhat of the nature of peaty loam and vary toward that type. The subsurface, 6% to 18 or 20 inches, consists of a brown sandy loam vary- ing with the surface. In the western areas it is quite light in color, varying to yellow. In the eastern part of the county, it is somewhat dark, and with depth becomes somewhat gray or drab, indicating poorer drainage in many cases. The subsoil is quite variable, in some places passing into a yellowish sand, in others into a gravelly till, while in others it becomes a drab or bluish-colored sand. This last is in the poorly drained areas. This type of soil requires for its improvement large use of organic matter. Being loose and better aerated than the brown silt loam, it suffers greater loss of that constituent, hence greater difficulty is found in maintaining it. Crop residues, legume crops, and manure must constitute the chief materials by which the organic-matter content is maintained. In phosphorus content, this type is the poorest in the county, and it is also very deficient in limestone. While the potassium content is large (25,000 pounds per acre of plowed soil), it is in part locked up in sand grains; hence, if satisfactory yields of legumes are not secured where the soil is well drained and treated with limestone and phosphorus, the addition of kainit or potassium chlorid may well be tried. 1915 ] Lake County 2 $ (b) Upland Timber Soils The upland forest soils are deficient in organic matter owing to the fact that the vegetable material from trees accumulates upon the surface and is either burned or suffers almost complete decay. Grasses which furnish large quantities of humus-forming roots do not grow to any large extent in forests. At the same time, the organic matter that had accumulated before timber began growing on these soils is being removed thru various decomposition processes, with the result that the content has become too low for best growth. Yellow-Gray Silt Loam (1034 and 1234) Yellow-gray silt loam is the most important and extensive soil type in Lake county. It is very irregularly distributed, but occupies mostly the rolling mo- rainal areas. This type covers 196.01 square miles, 125,447 acres, or 40.59 per- cent of the county. It varies greatly in topography — from the characteristic bil- lowy, or knob-and-basin, features of the moraines to the almost level morainal and intermorainal tracts. The surface soil, 0 to 6% inches, is a gray or yellowish gray silt loam, inco- herent and mealy, but not granular. The physical composition varies a great deal because of the removal by erosion in some places of the thin covering of loess, thus exposing the variable drift. Many local areas of sandy or gravelly loam are found in this type, but they are too small to be shown on the map. Likewise many small areas of dark soil such as the brown silt loam or black mixed loam are found in the slight depressions; these are also too small to be shown. The amount of organic matter contained in the surface soil of this type varies from 1.8 to 3.6 percent, with an average of 2.7, or 27 tons per acre. This wide variation is due to the relation of the type to other types, the content of organic matter increasing where it grades into brown silt loam (1026 or 1226) and decreasing where it passes into yellow silt loam (1035 or 1235). In some places erosion has reduced the content of organic matter much below the normal, so that many small areas are yellow in color. The subsurface stratum varies from 3 to 10 inches in thickness, being thin- ner on the more rolling areas. In color it is gray, grayish yellow, or yellow, some- what pulverulent, but becoming more coherent and plastic with depth. On some of the areas a stratum of gravel an inch or two in thickness is encountered at a depth of 10 to 24 inches. This is formed by the washing out of the fine material from the surface drift, as may be seen on the surface of exposed drift at the present time. It has subsequently been covered with a thin deposit of loess. The amount of organic matter is very low, amounting to only 1.1 percent, or 22 tons per acre, for a stratum lSy s inches in thickness. The subsoil is a yellow to a grayish yellow boulder clay. The deeper sub- soil contains large amounts of limestone and shows brisk effervescence with hydrochloric acid. In the management of this yellow-gray silt loam, one of the most essential points is the maintenance or increase of the organic matter. This is much more necessary with this type than with the brown silt loam, because this soil is natur- ally much more deficient in that constituent. The organic matter supplies nitro- gen, liberates mineral plant food, prevents running together, and on some of the Soil Beport No. 9 [April, 26 more rolling areas, prevents washing as well as gives better tilth to the soil under all conditions. Another essential is the application of ground limestone, so that clover, alfalfa, and other legumes may be grown more successfully. In many cases where limestone is present in the subsoil, the legume crops will grow very well, but fre- quently their growth may be profitably increased by the application of 2 to 5 tons per acre of limestone. Potassium is exceedingly abundant in this type of soil, while phosphorus is markedly deficient, as is readily seen from the tabular statements, which are well supported by the results already secured from the soil experiment field conducted for many years by the University of Illinois with the helpful cooperation of Mr. D. M. White, on his farm near Antioch in Lake county. (See Tables 3 and 4, pages 7 and 8.) Yellow Silt Loam (1035 and 1235) Yellow silt loam is found chiefly in the west quarter of the county where the highest part of the Valparaiso moraine occurs. The type here is not due pri- marily to erosion, as in most parts of the state, but to the irregularities produced in the piling up of the morainic material. Basin-like kettle-holes are found vary- ing from 25 feet or less to 75 and possibly 100 feet in depth. Rounded knobs are also quite characteristic of this moraine. The area of this type amounts to 38.5 square miles, 24,639 acres, or 8 percent of the county. The surface soil, 0 to 6% inches, is a yellow or yellowish gray silt loam, usually containing some sand and gravel. This stratum is usually formed from drift material, the loess, if there ever was any, having been removed by erosion. Owing to its derivation, the stratum varies a great deal in physical composition. The organic-matter content averages about 1.8 percent. The subsurface is composed of yellow drift material, as is also the subsoil. One of the best ways to manage this type is to keep it in permanent pasture. As a rule, it cannot be satisfactorily cropped in ordinary rotations, altho it may be used very successfully for long rotations with much pasture or meadow. Where this soil has been long cultivated and thus exposed to surface wash- ing, it is particularly deficient in nitrogen ; indeed, on such lands the low supply of nitrogen is the factor that first limits the growth of grain crops. This fact is very strikingly illustrated by the results from two pot-culture experiments re- ported in Tables 12 and 13, and illustrated in Plates 7 and 8. In one experiment, a large quantity of the typical worn hill soil was col- lected from two different places. 1 Each lot of soil was thoroly mixed and put in ten four- gallon jars. Ground limestone was added to all the jars except the first and last in each set, those two being retained as control or check pots. The elements nitrogen, phosphorus, and potassium were added singly and in com- bination, as shown in Table 12. As an average, the nitrogen applied produced a yield about eight times as large as that secured without the addition of nitrogen. While some variations in yield are to be expected, because of differences in the individuality of seed or other uncontrolled causes, yet there is no doubting the plain lesson taught by these actual trials with growing plants. ‘Soil for wheat pots from loess-covered unglaciated area, and that for oat pots from upper Illinois glaciation. 1915 ] Lake County 27 The question arises next, Where is the farmer to secure this much-needed nitrogen ? To purchase it in commercial fertilizers would cost too much ; indeed, under average conditions the cost of the nitrogen in such fertilizers is greater than the value of the increase in crop yields. But there is no need whatever to purchase nitrogen, for the air contains an inexhaustible supply of it, which, under suitable conditions, the farmer can draw upon, not only without cost, but with profit in the getting. Clover, alfalfa, cow- peas, and soybeans are not only worth raising for their own sake, but they have the power to secure nitrogen from the atmosphere if the soil contains the essen- tial minerals and the proper nitrogen-fixing bacteria. In order to secure further information along this line, another experiment with pot cultures was conducted for several years with the same type of worn hill soil as that used in the former experiment. The results are reported in Table 13. To three pots (Nos. 3, 6, and 9) nitrogen was applied in commercial form, at an expense amounting to more than the total value of the crops produced. In three other pots (Nos. 2, 11, and 12) a crop of cowpeas was grown during the late summer and fall and turned under before the wheat or oats were planted. Plate 7.— Wheat in Pot-Cultuke Experiment with Yellow Silt Loam of Worn Hill Land (See Table 12) Table 12. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (Grams per pot) Pot No. 1 None 2 Limestone . Soil treatment applied 3 Limestone, nitrogen 4 Limestone, phosphorus 5 Limestone, potassium 6 Limestone, nitrogen, phosphorus. . 7 Limestone, nitrogen, potassium . . . 8 Limestone, phosphorus, potassium, 9 10 Limestone, nitrogen, phosphorus, potassium. None Wheat Oats 3 5 4 26 3 4 45 6 3 34“ 33 2 34 3 5 38 46 5 38 5 Average yield with nitrogen i 32 42 Average yield without nitrogen I 3 5 Average gain for nitrogen 29 37 Soil Report No. 9 [April, 28 Pots 1 and 8 served for important comparisons. After the second cover crop of cowpeas had been turned under, the yield from Pot 2 exceeded that from Pot 3 ; and in the subsequent years the legume green manures produced, as an average, rather better results than the commercial nitrogen. This experiment confirms that reported in Table 12, in showing the very great need of nitrogen for the improvement of this type of soil, and it also shows that nitrogen need not be purchased but that it can be obtained from the air by growing legume crops and plowing them under as green manure. Of course the soil can be very markedly improved by feeding the legume crops to live stock and returning the resulting farm manure to the land, if legumes are grown frequently enough and if the farm manure produced is sufficiently abundant and is saved and applied with care. As a rule, it is not advisable to try to enrich this type of soil in phosphorus, for with the erosion that is sure to occur to some extent the phosphorus supply will be renewed from the subsoil. One of the most profitable crops to grow on this land is alfalfa. To get alfalfa well started may require the use of limestone, thoro inoculation with nitrogen-fixing bacteria, and a moderate application of farm manure. If manure is not available, it is well to apply about 500 pounds per acre of acid phosphate or steamed bone meal, mix it with the soil, by disking if possible, and then plow it under. The limestone (if needed) should be applied after plowing and should be mixed with the surface soil in the preparation of the seed bed. The special Plate 8.— Wheat in Pot-Cultuke Experiment with Yellow Silt Loam of Worn Hill Land (See Table 13) Table 13. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land and Nitrogen-Fixing Green Manure Crops (Grams per pot) Pot No. Soil treatment 1903 Wheat 1904 Wheat 1905 Wheat 1906 Wheat | 1907 Oats 1 None 5 4 4 4 6 2 Limestone, legume 10 17 26 19 37 11 Limestone, legume, phosphorus 14 19 20 18 27 12 Limestone, legume, phosphorus, potassium. . 16 20 21 19 30 3 Limestone, nitrogen 17 14 15 9 28 0 Limestone, nitrogen, phosphorus 26 20 18 18 30 9 Limestone, nitrogen, phosphorus, potassium 31 34 21 20 26 8 Limestone, phosphorus, potassium 3 3 5 3 7 1915 ] Lake County 29 purpose of this treatment is to give the alfalfa a quick start in order that it may grow rapidly and thus protect the soil from washing. Yellow-Gray Sandy Loam (1064) Yellow-gray sandy loam occupies only small areas in Lake county, amount- ing to 488 acres. It is practically all found in the western part in the most broken of the morainal ridges. The surface soil, 0 to 6% inches, is a yellow or grayish yellow sandy loam, frequently containing from 15 to 25 percent of gravel. In some small areas this gravel may be absent ; its presence is due to the fact that the soil is made of a sandy till. The organic-matter content is 1.8 percent, or about 18 tons per acre. The subsurface stratum, from 3 to 8 inches in thickness, differs from the surface in being of a lighter color, owing to the smaller amount of organic mat- ter present, about .3 percent. At a depth of about 12 to 16 inches on much of this type, a stratum of gravelly material exists thru which it is practically im- possible to bore with an auger. The subsoil varies from a somewhat gravelly till to almost pure sand. For the improvement of this type, the addition of organic matter and nitro- gen is very essential, and limestone should be applied liberally for the best re- sults with legumes. The porous subsoil affords such a deep feeding range for plant roots that the addition of phosphorus is not likely to be necessary or profit- able. Yellow-Gray Sandy Loam on Gravel (1064.4) Yellow-gray sandy loam on gravel occurs only in the northwestern part of the county, and there in limited areas. The type differs but little from yellow- gray sandy loam except that it contains much more gravel in the subsoil and for that reason is less desirable. It occupies 1.48 square miles, or .3 percent of the entire area of the county. The stratum of gravel varies a great deal, both as to depth and physical composition. In depth it varies from 12 to 30 inches ; in composition it is sandy, or a sand in some places, and in others a mixture of sand, gravel, and small stones not over two inches in diameter. The management of this type should be the same as for the yellow-gray sandy loam. Alfalfa does fairly well on this type, and sweet clover would do equally well. Dune Sand (1081 and 1281) Dune sand is found in the vicinity of Fox Lake, and also along the old lake shore north of Waukegan. It covers 1.47 square miles. Its presence is due to the action of wind, and possibly the waves, in piling the sand up from the lake shore. The surface soil contains about 2.25 percent of organic matter, while the subsurface has about .8 percent. In the management of this type, limestone should be applied and legume crops should be prominent in the rotation unless large amounts of organic mat- ter can be added in some other form. The only other addition suggested is potas- sium, but this should not be applied on a large scale unless found profitable by careful trial on small areas. 30 Soil Report No. 9 [April, For results from field experiments on sand soil, see pages 246 to 249 of Bulletin 123 of this station. 1 In the experiments there described (conducted in Tazewell county), the average value of the increase per acre per annum was $12.12 from nitrogen, $2.96 from potassium (costing $2.50), and 4 cents from phosphorus, the order of crops being corn, corn, oats, wheat, corn, corn. The nitrogen applied cost $15 in commercial form, but of course by growing legume crops, which are worth raising for their own sake, that element may be secured from the air without cost. Gravelly Loam (1090 and 1290) Gravelly loam occurs principally in the morainal regions of the northwest part of the Lake county, altho some small areas are found in other parts. The total area aggregates 611 acres, or .2 percent of the area of the county. The surface soil is composed of a large amount of gravel, in many cases amounting to 60 or 70 percent. Occasionally small stones an inch or two in diameter are found mixed with the gravel. The organic-matter content amounts to approximately 3 percent, or 30 tons per acre. The subsurface soil contains about one-fourth as much as the surface. This type is of very little agricultural significance. The treatment recom- mended is the same as that for yellow-gray sandy loam (1064). It may well be left in permanent pasture. (c) Terrace Soils Terrace soils occur along streams and were formed at a time when the streams were much larger than at present and carried large amounts of coarse material, such as sand and gravel. This Overloading of the streams caused deposition along their courses which resulted in the formation of terraces, bench lands, or second bottom lands. Fine material, later deposited over this sand and gravel, forms the present soil. Brown Silt Loam over Gravel (1527) Brown silt loam over gravel is found along the Des Plaines river near the southern part of the county where the stream formed its widest terrace. The deposit of gravel here is not very deep, but it furnishes a very effective means for the natural drainage of these areas. This type occupies 1.85 square miles. The surface soil, 0 to 6% inches, is a brown silt loam, with some sand, but rarely containing enough to make it a sandy loam. The average amount of organic matter present is 5.4 percent, or 54 tons per acre. The subsurface soil consists of a brown silt loam, becoming yellow at about 16 inches and passing into the subsoil at a depth of 18 inches. The subsurface stratum contains about 2.5 percent of organic matter. The subsoil varies a great deal, in some cases containing a considerable amount of sand and fine gravel. It is generally a yellow clayey silt, pervious, and well drained. The depth to the gravel varies from 38 to 48 inches. It con- sists of a mixture of medium and fine gravel with some coarse sand. This type requires practically the same management as the brown silt loam, 'Bulletin 123 may be had from the Experiment Station upon request. 1915 ] Lake County 31 altho in some cases there may be more need of organic matter than in some phases of the brown silt loam. Alfalfa should do well on this type. Yellow-Gray Sandy Loam on Gravel (1564.4) Yellow-gray sandy loam on gravel occurs only along the Des Plaines river and is limited largely to the east side of this stream. The total area is 2.25 square miles. The surface soil, 0 to 6% inches, varies in color from a yellow to a gray, and in texture from a loam to a sand. These variations are so limited in area and so badly mixed that it is impossible to represent them on the map. In some places there are slight ridges that indicate low dunes ; these give rise to a very sandy phase. The subsurface stratum is as variable as the surface. In small areas the subsurface is a sandy clay or sandy clay loam, while in others it is a yellow sand. The organic-matter content of the subsurface is higher in the more silty or clayey parts, but in the more sandy phase it contains almost no organic matter. The subsoil varies in different parts of the Des Plaines valley. In the north- ern part it is decidedly gravelly, while in the southern, sand prevails. The depth to the sand or gravelly stratum varies from over 30 inches in many places to less than 15 inches in others. In the southern half of the county this type is not under cultivation, but is almost entirely covered with a young growth of forest trees. Where it is under cultivation, the treatment should be about the same as for the yellow-gray silt loam, except as regards phosphorus. With the porous character of the soil and subsoil, and the extensive feeding range thus afforded plants, the supply of phos- phorus naturally contained in this soil should be adequate for large crops. Brown Sandy Loam on Gravel (1560.4) Brown sandy loam on gravel is found principally along the Des Plaines river and is similar to yellow-gray sandy loam on gravel except that the forests that have recently grown up here have not reduced the organic-matter content to such a low amount. Part of the type in the southern part of the county has never been covered with forest. In topography the type shows a slight ridging, due to the action of wind in forming sand dunes or of the water in forming bars. The total area is 2.4 square miles, or .5 percent of the area of the county. The surface soil, 0 to 6% inches, varies in color from a light to a dark brown, almost black, and in texture from a loam to a sandy loam. The subsurface soil is a light brown loam to sandy loam, having a thickness of 5 to 12 inches with an average of 9 to 10 inches. It passes into the gravelly, sandy subsoil, which is made up of medium and fine gravel, mixed with more or less coarse sand. The depth of the gravel from the surface varies from 14 to 30 inches and even more in small local areas. The bed of gravel itself is probably not over 20 feet in depth in any place, and toward the southern part of the county it is much less than that. In many places it is being taken out for use on roads. The presence of gravel in the subsoil gives excellent drainage to this type, and in seasons of drouth, the crops may suffer because of lack of moisture. Only the ordinary crops, as a rule, are grown on this type, but it is fairly 32 Soil Keport No. 9 [April, well adapted to the growth of alfalfa and deep-rooting crops. Manure, crop residues, or legume crops should be turned under in order to maintain the or- ganic matter and nitrogen, but the addition of phosphorus is not likely to be profitable. Gravelly Loam on Gravel (1590.4) Gravelly loam on gravel covers one area of 179 acres in Section 22, Town 46 North, Range 11 East. The surface soil, 0 to 6% inches, consists of a brown, gravelly loam, the gravel present amounting to 60 to 75 percent. The content of organic matter is about 3 percent. The subsurface stratum contains even a larger amount of gravel than the surface, with a proportionately smaller amount of organic matter. A sample could not be obtained to a depth of more than 20 inches. The subsoil con- sists of various grades of gravel mixed with a few small stones. This is a very poor type of soil, owing to the fact that it does not have much power for retaining moisture in times of drouth, and the plant food leaches out readily. The liberal use of legume crops and organic manures is advised. (d) Swamp and Bottom-Land Soils Deep Peat (1401) Deep peat is found in nearly all parts of Lake county, occurring on the old beach of Lake Michigan, in the bottom lands of the streams, in the depressions of the moraines, and around the margins of many of the lakes. The total area is 38.1 square miles, 24,382 acres, or 7.89 percent of the area of the county. The deep peat is formed by the growth of both grasses and mosses. In one area in Section 35, Town 46 North, Range 10 East, the peat was found to be forming entirely by the accumulation of the sphagnum moss, independent of the growth of grasses ; in other areas, both grasses and mosses contribute to the deposit. The surface soil, 0 to 6% inches, is a black or brown peat, more or less de- composed. The drained areas have undergone greater decomposition because of better aeration, while the moss-covered or grass-covered peat of the undrained areas has changed but little. The content of organic matter varies from 61 to 77 percent, with an average of 70.5 percent. The subsurface soil, 6% to 20 inches, consists of black or brown peat that usually shows the texture of the material from which it was produced. The subsoil, from 20 to 40 inches, is usually a brown peat, altho in some small areas sand or silty material may form the subsoil below 30 inches. This latter phase is almost invariably drab in color, due to deoxidation b^ organic acids. , I A Because of lack of drainage, this type of soil in Lake county has not been largely cultivated, except in the small areas. It does, however, supply a large amount of hay that is used to a considerable extent for packing ice in the large ice houses on the shores of the lakes. As a rule, it is not desirable to attempt to drain this type by means of tiles unless they can be laid deep enough to place them in the clayey or silty subsoil. Tiles laid in peat soon get out of line. As shown in Table 2, deep peat contains in one million pounds of surface soil about 32,000 pounds of nitrogen, 1,500 pounds of phosphorus, and 3,900 li)15 ] Lake County 33 pounds of potassium. This shows in the surface 6% inches of an acre nearly five times as much nitrogen as the brown silt loam prairie. In phosphorus content these two soil types are about equal, but the peat contains less than one-tenth as much potassium as the brown silt loam. Thus the total supply of potassium in the peat to a depth of 7 inches (3,900 pounds) would be equivalent to the potas- sium requirement (73 pounds) of a hundred-bushel crop of corn for only 53 years ; or if the equivalent of only one-fourth of one percent of this is annually available, in accordance with the rough estimate suggested in Bulletin 123, then about 10 pounds of potassium would be liberated annually, or sufficient for about 14 bushels of corn per acre. In Table 14 are given all results obtained from the Manito (Mason county) experiment field on deep peat, which was begun in 1902 and discontinued after 1905. The plots in this field were one acre 1 each in size, 2 rods wide and 80 rods long. Untreated half -rod division strips were left between the plots, which, how- ever, were cropped the same as the plots. The results of four years’ tests, as given in Table 14, are in complete har- mony with the information furnished by the chemical composition of peat soil as compared with that of ordinary normal soils. Where potassium was applied, the yield was from three to four times as large as where nothing was applied. Where approximately equal money values of kainit and potassium chlorid were applied, slightly greater yields were obtained with the potassium chlorid, which, however, supplied about one-third more potassium than the kainit. On the other hand, either material furnished more potassium than was required by the crops produced. The use of 700 pounds of sodium chlorid (common salt) produced no appre- ciable increase over the best untreated plots, indicating that where potassium is itself actually deficient, salts of other elements cannot take its place. Applications of 2 tons per acre of ground limestone produced no increase in the corn crops, either when applied alone or in combination with kainit, either the first year or the second. Table 14. — Coen Yields in Soil Experiments, Manito Field; Typical Deep Peat Soil (Bushels per acre) Plot No. Soil treatment for 1902 Corn 1902 Corn 1903 Soil treatment for 1904 Corn 1904 Corn 1905 Four crops 1 None 10.9 8.1 None 17.0 12.0 48.0 42.9 2 None 10.4 10.4 Limestone, 4000 lbs .... 12.0 10.1 3 Kainit, 600 lbs 30.4 32.4 j Limestone, 4000 lbs . . \ 49.6 47.3 159.7 \ Kainit, 600 lbs 1 1 Kainit, 1200 lbs \ 4 "j Aeidulat ’d bone, 350 lb. j 30.3 33.3 i Kfnnit 1900 lb« ^ ) Steamed bone, 395 lbs . t 53.5 47.6 164.7 5 Potassium chlorid, 200 lbs 31.2 33.9 Potassium chlorid, 400 lbs. . . . 48.5 52.7 166.3 6 Sodium chlorid, 700 lbs. 11.1 13.1 • None 24.0 22.1 70.3 7 Sodium chlorid, 700 lbs. 13.3 14.5 Kainit, 1200 lbs 44.5 47.IT 8 Kainit, 600 lbs 36.8 37.7 Kainit, 600 lbs 44.0 46.0 164.5 9 Kainit, 300 lbs 26.4 25.1 Kainit, 300 lbs 41.5 32.9 125.9 10 None 14.9' 14.9 None 26.0 T5X 69.4 Estimated from 1903; no yield was taken in 1902 because of a misunderstanding. 'In 1904 the yields were taken from quarter-acre plots because of severe insect injury on the other parts of the field. 34 Soil Report No. 9 [April, Reducing the application of kainit from 600 to 300 pounds for each two- year period, reduced the yield of corn from 164.5 to 125.9 bushels. The two applications of 300 pounds of kainit (Plot 9) furnished 60 pounds of potassium for the four years, an amount sufficient for 84 bushels of corn (grain and stalks). Attention is called to the fact that this is practically the difference between the yield of Plot 9 (125.9 bushels) and the yield obtained from Plot 2 (42.9 bushels), the poorest untreated plot. Medium Peat on Clay (1402) Medium peat on clay occurs in low, swampy areas, where the peat has not developed to a greater thickness than 30 inches. The total area is 640 acres, equivalent to 1 square mile, or .21 percent of the area of the county. The surface, 0 to 6% inches, is a brown or black peat, the decomposition varying with cultivation and drainage. The subsurface, from 6% inches to the depth of the peat, is usually a brownish peat that has not undergone a great amount of decomposition. In the classification used by this station, medium peat extends from 12 to 30 inches in depth, and in most areas the subsurface is usually taken as extending to the silty, clayey, or sandy layer. This gives a large variation in the thickness of the sub- surface, but it is sampled to a depth of 20 inches. The subsoil in this type consists of a silty clay and almost invariably is of light drab or bluish color, owing to deoxidation of iron by organic acids. The treatment advised for this type is the same as for deep peat (1401), but thoro trials should be made with potassium in advance of extensive use. Drainage is an easier matter because tile may usually be placed in the clay. Medium Peat on Sand (1402.2) Medium peat on sand is found only on the old beach of Lake Michigan north of Waukegan, and here in very limited areas large enough to map. The total area is 284 acres. The surface soil, 0 to 6% inches, is a brownish, somewhat decomposed peat mixed with more or less sand. The subsurface extends to a depth of 12 to 20 inches, passing into a drab- colored sand that continues to an indefinite depth. Practically none of this is under cultivation, altho some of it is used for pasture. Potassium is the only material suggested for trial applications. Shallow Peat on Clay (1403) Shallow peat on clay occurs in small areas on the upland and is usually not very uniform. The total area is 371 acres. The surface soil, 0 to 6% inches, consists of a dark, peaty material mixed with more or less sand, silt, or clay. It varies from pure peat to a very black silt or clay loam. Very few of these areas are under cultivation, but are mostly in pasture. The tramping of cattle has produced hummocks, which vary in height from 4 to 12 inches. An illustration of these is shown. in Plate 9. The subsurface soil is usually a brown silt loam, changing into a drab or bluish color at 12 to 16 inches in depth. Lake County 35 1915] The subsoil is of the mottled drabbish or yellowish color and usually con- tains some fragments of limestone. Alkali patches are of frequent occurrence. The first requirement of this type is good drainage. Where the surface is deficient in potassium, deeper plowing will bring abundance of it from the sub- surface to be incorporated with the plowed soil. Peaty Loam (1410) Peaty loam is found in small areas in the depressions on the high terrace of Lake Michigan in the northeast part of the county. There is also one larger area in a broad valley west of Lake Bluff. The total area is not large, amounting to only 2.35 square miles, or .49 percent of the area of the county. The surface soil, 0 to 6% inches, is a black, peaty loam. The amount of organic matter and sand varies in different areas, the organic matter varying from 10 to 25 percent or even more. The subsurface soil is quite variable. In some areas it is a drabbish or bluish sand mixed with a variable amount of organic matter; in others it is a brown sandy loam ; while in others it is clayey or silty. The subsoil varies from a sand to a sand containing a considerable amount of silt and clay. The first requirement of this type is good drainage. Some areas may re- quire the application of potassium in order to produce well. This is true espe- cially of those areas where the soil contains little or no clay. Alkali is frequently present in sufficient quantities to do great injury to crops, more particularly to Plate 9. — Hummocks on “Bog” Land 36 Soil Refort No. 9 [April, corn. The alkali consists chiefly of harmless carbonate (limestone) with smaller amounts of injurious magnesium carbonate. In some cases these peaty soils actually contain a good percentage of total potassium, more commonly in the subsurface or subsoil but sometimes in the sur- face soil also ; and yet the untreated soil may be unproductive, while the addition of potassium salts may produce large and very profitable increases in the yield of corn, oats, etc. In pot-culture experiments we have even been able by the addition of potassium sulfate to correct to a considerable extent the injurious property of magnesium carbonate that has been purposely applied to ordinary brown silt loam prairie soil known to contain abundance of available potassium. These facts are mentioned here because the Experiment Station recom- mends, tentatively, the application of potassium salt to all classes of peaty and alkali soils that are unproductive after being well drained, whenever the supply of farm manure is insufficient. It should be understood that plenty of farm manure, preferably quick-acting, or readily decomposable, manure, such as horse manure, will supply potassium and thus accomplish everything that potassium salts can accomplish; on some swamp soils manure produces good results even where potassium is without effect. Black Mixed Loam (1450) Black mixed loam occurs in many of the low, swampy regions where organic matter has not accumulated sufficiently for the formation of peats. The morainal areas contain large numbers of small ponds, in which this type has developed, but they are too small to be shown on the map. The total area of this type is 19.72 square miles, 12,622 acres, or 4.09 percent of the area of the county. The surface soil, 0 to 6% inches, varies from a peat to a black clay, black silt, or black sandy loam. The areas of these different phases are so small, how- ever, and so badly mixed, that it is practically impossible to make any satisfac- tory separation of them into distinct types. For this reason the type is called black mixed loam. The content of organic matter varies from 6 to 20 percent. The subsurface soil varies to a less extent than the surface. It is generally a dark silt or clay loam with some sand and gravel to a depth of 14 to 16 inches. The subsoil varies from a drab to a yellow clayey silty material that is made up largely of boulder clay. Many limestone gravels are found in this stratum. On the surface of this type are found many glacial boulders, mostly gran- ites, that have either been left when the other material has been removed by water, or been brought to the surface by the action of frost. In many cases they are so numerous that cultivation would be impossible without removing them. They vary in size from a few inches to several feet in diameter. In the management of this type, the first essential is thoro drainage. The variability of the soil makes it rather difficult to suggest any treatment that will apply to the type as a whole. It may be found that some areas will need applica- tions of potassium. This is true of the small peaty areas as well as the alkali spots that are quite common in the type. Comparatively little of this type is under cultivation ; nearly all of it is either in pasture or meadow. The tramping of stock on this type produces hummocks, or “bogs,” as they are frequently called by the farmers of this vicinity. The height of these may 1915 ] Lake County 37 be increased by freezing and thawing to 12 or 15 inches. Driving over such an area as this with implements is practically impossible. A ‘ ‘ bog cutter, ’ ’ consist- ing of a series of either straight or curved knives, is used for reducing the hum- mocks before plowing. (See Plate 9.) Mixed Loam ( Bottom Land ) (1454) Mixed loam occurs along the streams. In many instances it is very much like the black mixed loam (1450) ; as a rule, however, it has received sufficient deposit from overflow to give it a more uniform character. The total area of this type is 8.51 square miles, 5,446 acres, or 1.76 percent of the area of the county. The surface soil, 0 to 6% inches, is brown to black in color, varying in tex- ture from a silt loam to a sandy loam. The streams of this county overflow less than in other parts of the state because the numerous lakes act as reservoirs giving a steady flow. The lakes also act as silt basins, in which the sediment settles. For these reasons there is less sediment carried and deposited on the flood plains. The amount of organic matter varies from 5 to 10 percent with an average of 7.7 percent, or 77 tons per acre. The subsurface soil, 6% to 20 inches, varies from a brown silt loam to a brown sandy loam, and is a little lighter in color than the surface soil. The subsoil varies from light brown to a yellowish or drabbish color, indi- cating that sufficient time has elapsed for the formation of a distinct subsoil. This occurs only where sedimentation takes place slowly. Because of lack of drainage, comparatively little of this type is under culti- vation. It makes good pasture land, and possibly that will be its principal use for years to come. Drainage is the first thing necessary. Where overflow occurs, high fertility is likely to be maintained. Beach Sand (1482) Beach sand, which might be called mixed sand and peat, extends from Wau- kegan to the state line and represents the beach of Lake Chicago. Its greatest width is about one mile. The area consists of a large number of sand ridges with peat deposits between them. These ridges are usually but a few rods wide, and still fewer rods apart, and the peat is represented by such small areas that it is practically impossible to indicate them on the map. The sand in some places has a covering of weeds, black oak, or stunted white pine. The soil is so variable here that it is practically impossible to give a description of the different strata, since in many cases a rod either way would mean an entire change of type. If drained, the treatment likely to be profitable will be suggested by a study of “dune sand” and “deep peat,” described in the preceding pages. Lakes Lake county contains 47 lakes, having a total area of 18 square miles, 11,512 acres, or 3.72 percent of the entire area of the county. Many of these lakes have swampy shores, which fact indicates that a gradual extinction is going on and that in time they will be filled with organic deposits. Many of the peaty areas are without doubt extinct lakes that have been filled by the accumulation of organic matter. 38 Soil Report No. 9 [April, APPENDIX A study of the soil map and the tabular statements concerning crop require- ments, the plant-food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil im- provement, and a careful study of the discussion of general principles and of the descriptions of individual soil types, will furnish the most necessary and use- ful information for the practical improvement and permanent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and important soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility in Illinois Soils,” which contains a colored general soil-survey map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils” Bulletin No. 94, “Nitrogen Bacteria and Legumes” Bulletin No. 115, '‘Soil Improvement for the Worn Hill Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Rotation on the Common Prairie Lands of Illinois ’ ’ Circular No. 82, “Physical Improvement of Soils” Circular No. 110, “Ground Limestone for Acid Soils” Circular No. 127, “Shall We Use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, “Results of Scientific Soil Treatment” and “Methods and Results of Ten Years’ Soil Investigation in Illinois” Circular No. 165, “Shall We Use ‘Complete’ Commercial Fertilizers in the Corn Belt?” Circular Nc. 167, “The Illinois System of Permanent Fertility” Note. — Information as to where to obtain limestone, phosphate, bone meal, and potas- sium salts, methods of application, etc., will also be found in Circulars 110 and 165. Soil Survey Methods The detail soil survey of a county consists essentially of ascertaining, and indicating on a map, the location and extent of the different soil types ; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential: first, careful, well-trained men to do the work; second, an accurate base map upon which to show the results of the work ; and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal variations and lim- its, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will sur- vey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries must match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil mapping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construc- tion of these maps, while the most trustworthy county map available is used in 1915 J Lake County 39 locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and corrected if wrongly located. In order to make these verifications and corrections, each survey party is pro- vided with an odometer for measuring distances, and a plane table for deter- mining directions of angling roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, ditches, streams, and necessary corrections are placed in their proper locations upon the map while the mapper is on the area; Each section, or square mile, is divided into 40-acre plots on the map, and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils for this purpose being carried in the field. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is carried by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while distances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be located with as high a degree of ac- curacy as can be indicated by pencil on the scale of one inch to the mile. Soil Characteristics The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type grades into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil- type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, al- luvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) the native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical, or me- chanical, composition of the different strata composing the soil, as the percent- ages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) the agricultural value, based upon its natural productiveness; (10) the ultimate chemical composition and reaction. The common soil constituents are indicated in the following outline : f Organic ("Comprising undecomposed and partially decayed matter \ vegetable or organic material . .001 mm. 1 and less 001 mm. to .03 mm. . .03 mm. to 1. mm. ... 1. mm. to 32 mm. . . .32. mm. and over Further discussion of these constituents is given in Circular 82. Soil constituents f Clay . . Inorganic J Sands ioESi *25 millimeters equal 1 inch. 40 Soil Report No. 9 [April, Groups op Soil Types The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand. Some silt and a little clay may be present. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 25 to 50 percent of gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel and much sand. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Rock outcrop — Usually ledges of rock having no direct agricultural value. More or less organic matter is found in all the above groups. Supply and Liberation of Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop ; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which it is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly important, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually pres- ent in the soil strata sampled and analyzed, but the rate of liberation is gov- erned by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are limestone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may be supplied also by green- manure crops and crop residues, such as clover, cowpeas, straw, and corn stalks. The rate of decay of organic matter depends largely upon its age and origin, 1915 ] Lake County 41 and it may be hastened by tillage. The chemical analysis shows correctly the total organic carbon, which represents, as a rule, but little more than half the organic matter; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly 20 tons of organic matter. But this organic mat- ter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cowpeas plowed under may have greater power to liberate plant food than the 20 tons of old, inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent addi- tions of active organic matter, whether in applications of farm manure, in legume crops, or in grass-root sods of old pastures. Probably no agricultural fact is more generally known by farmers and land- owners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that with the normal rainfall of Illi- nois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such commodity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts of potassium, magnesium, calcium, etc., for the use of the growing crop. As already explained, fresh organic matter decomposes much more rapidly than old humus, which represents the organic residues most resistant to decay and which consequently has accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old, resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and thus furnish or lib- erate organic matter and inorganic food for bacteria, the bacteria, under such favorable conditions, appearing to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when composted with, fresh farm manure ; so that two tons of the compost 1 may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bac- terial action is also promoted by the presence of limestone. “In his book, “Fertilizers,” published in 1839, Cuthbert W. Johnson reported such com- post to have been much used in England and to be valued as highly, “weight for weight, as farm-yard dung.” 42 Soil Report No. 9 [April, The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter ; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil; while in old, worn soils that are greatly in need of fresh, active, organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. Soils of cut-over or burnt-over timber lands sometimes contain so much partially decayed wood or charcoal as to destroy the value of the nitrogen-carbon ratio for the purpose indicated. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of' these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches, among our common agricultural plants) secure from the soil alone six elements (phos- phorus, potassium, magnesium, calcium, iron, and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a build- ing is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay; and, where the land is properly drained and properly tilled, such crops would fre- quently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the absolute needs of the crops. Crop Requirements The accompanying table shows the requirements of wheat, corn, oats, and clover for the five most important plant-food elements which the soil must fur- nish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are never known to limit the ffield of general farm crops grown under normal conditions.) 1915 ] Lake County 43 Table A. — Plant Pood in Wheat, Corn, Oats, and Clover Produce Nitro- Phos- Potas- Magne- Cal- Kind Amount gen phorus sium sium cium lbs. lbs. lbs. lbs. lbs. Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw 2% tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs % ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2% tons 31 5 52 7 15 Clover seed 4 bu. 7 2 3 1 1 Clover hay 4 tons 160 20 120 31 117 Total in grain and seed 244 1 42 51 16 4 Total in four crops.. 510 1 77 322 68 168 J Thcse amounts include the nitrogen contained in the clover seed or hay, which, how- ever, may be secured from the air. To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as possible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the 100-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with lime- stone, phosphorus, and manure). The importance of maintaining a rich surface soil cannot be too strongly emphasized. This is well illustrated by data from the Rothamsted Experiment Station, the oldest in the world. On Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well ferti- lized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (0 to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods of Liberating Plant Food Limestone and decaying organic matter are the principal materials which the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria, which have power to transform the insoluble and unavailable organic 44 Soil Report No. 9 [April, nitrogen into soluble and available nitrate nitrogen. At the same time, the products of this decomposition have power to dissolve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing what- ever to the soil, but always leaves it poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed bed for root development and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows: (1) If the soil is acid, apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC0 3 MgC0 3 ), which con- tains both calcium and magnesium and has slightly greater power to correct soil acidity, ton for ton, than the ordinary calcium limestone (CaC0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years. On strongly acid soils, or on land being prepared for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks), or by using for feed and bed- ding practically all the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines: First year, corn. Second year, corn. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rotation. In grain farming, with small grain grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desiS&d. The system may be reduced to a five- year rotation by cutting out either the second or the sixth year, and to a four- year system by omitting the fifth and sixth years. 1915] Lake County 45 With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover; or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Good three-year rotations are: Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover) , and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat, (4) clover, and (5) wheat (and clover) allows legumes to be seeded four times. Alfalfa may be grown on a sixth field for five or six years in the combination, rotation, alternating between two fields every five years, or rotating over all the fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute sweet clover or alsike for red clover in about every third rotation, and at the same time to discontinue its use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover crop (seeded at the last cultivation) in the southern part of the state, and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named : 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires 1% pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. 1 ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. In grain crops, such as wheat, corn, and oats, about two-thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. (See also discussion of “The Potassium Problem,” on pages following.) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in consid- erably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far secured shows posi- tively that fine-ground natural rock phospmfte can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil 46 Soil Report No. 9 [Aprn, improvement. The first application may well be one ton per acre, and subse- quently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total application of from three to five or six tons per acre of raw phosphate containing 121/2 percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in carload lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phos- phate. Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about 1^/2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rota- tion, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply .of decaying organic matter has been made adequate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or a mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phos- phorus as well as to furnish available potassium and magnesium, and for a few years such use of kainit may be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for supplying decaying organic matter, since this will necessitate returning to the soil the potassium contained in the crop residues from grain farming or the manure produced in live-stock farming, and will also provide for the liberating of potas- sium from the soil. (Where hay or straw is sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow-gray silt loam and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tends to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently ; but where such lands are farmed under such a system, not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time; and where the soil is acid a liberal use of limestone, as top- dressings if necessary, and occasional reseeding with clovers will benefit both the pasture and indirectly the grain crops. 1915] Lake County 47 Advantage of Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years ; but even a partial stand of clover the first time will probably provide a thousand times as many bacteria for the next clover crop as one could afford to apply in artificial inoculation, for a single root-tubercle may contain a million bacteria developed from one during the sea- son’s growth. This is only one of several advantages of the second course of the rotation over the first course. Thus the mere practice of crop rotation is an advantage, especially in helping to rid the land of insects and foul grass and weeds. The clover crop is an advantage to subsequent crops because of its deep-rooting char- acteristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage ; and in systems of permanent soil improve- ment, such as are here advised and illustrated, more limestone and more phos- phorus are provided than are needed for the meager or moderate crops pro- duced during the first rotation, and consequently the crops in the second rota- tion have the advantage of such accumulated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. This means that these systems tend positively toward the making of richer lands. The ultimate analyses recorded in the tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter ; and the accumulated information from careful and long-continued investigations in different parts of the United States clearly establishes the fact that in general farming these essen- tials can be supplied with greatest economy and profit by the use of ground nat- ural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applica- tions are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt, such as kainit, is used, it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for moi’e than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 60 years (1852 to 1911), the yield of wheat was 12.7 bushels on untreated land and 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied. As further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of magnesium raised it to 29.2 bushels ; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied, the wheat crop removed an- 48 Soil Report No. 9 [April, nually an average of 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained an abundance of lime- stone, but no organic matter was provided, except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 60 years (1852 to 1911) was 14.2 bushels on untreated land, 38.1 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus were applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.5 bushels. Where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average was 43.0 bushels. Thus, as an average of 60 years, the use of sodium produced 1.8 bushels less wheat and 1.5 bushels more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of .potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop ; but this must be expected to occur in time where no potassium is returned in straw or manure, and no pro- vision made for liberating potassium from the supply still remaining in the soil. If the wheat straw, which contains more than three-fourths of the potassium removed in the wheat crop (see Table A), were returned to the soil, the neces- sity of purchasing potassium in a good system of farming on such land would be at least very remote, for the supply would be adequately maintained by the actual amount returned in the straw, together with the additional amount which would be liberated from the soil by the action of decomposition products. While about half the potassium, nitrogen, and organic matter, and about One-fourth the phosphorus contained in manure is lost by three or four months ’ exposure in the ordinary pile in the barn yard, there is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while in average live-stock farming the animals destroy two-thirds of the or- ganic matter and retain one-fourth of the nitrogen and phosphorus from the food they consume, they retain less than one-tenth of the potassium ; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 6% inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent cul- tivation) will permanently maintain the potassium in grain farming by re- newal from the subsoil, provided one-third of the potassium is removed by crop- ping before the soil is carried away. From all these facts it will be seen that the potassium problem is not one of addition but of liberation ; and the Rothamsted records show that for many years other soluble salts have practically the same power as potassium to increase crop yields in the absence of sufficient decaying organic matter. Whether this 1915] Lake County 49 action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other ele- ments, is not known, but where much potassium is removed, as in the entire crops at Rothamsted, with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909, and 1910 on the Fairfield experiment field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium and costing $5.10, increased the yield of corn by 9.3 bushels per acre ; while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit paid for itself ; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield included an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure were applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bushels, while the 600 pounds of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was produced by the addition of either 1 potassium sulfate or kainit ; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for, and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant-food elements, especially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown by chemical analysis that potassium salts and most other soluble salts increase the solubility of the phosphorus in soil and in rock phosphate; also that the addition of glucose with rock phosphate in pot-culture experiments increases the availability of the phosphorus, as measured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the or- ganic matter of the food they consume, it it easy to determine from Table A that more organic matter will be supplied in a proper grain system than in a strictly live-stock system ; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious interference with the capillary movement of the soil moisture, a common danger from plowing under too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming or when both grain and straw are sold, of course the draft on potas- sium will then be so great that in time it must be renewed by some sort of appli- cation. As a rule, farmers following this practice ought to secure manure from town, since they furnish the bulk of the material out of which manure is pro- duced. so Soil Report No. 9 [April, Calcium and Magnesium When measured by the actual crop requirements for plant food, magnesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses 1 of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of cal- cium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of magnesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in 1905. Prac- tically the same amount of calcium was found, by analyses, in the Rothamsted drainage waters. Common limestone, which is calcium carbonate (CaC0 3 ), contains, when pure, 40 percent of calcium, so that 800 pounds of limestone are equivalent to 320 pounds of calcium. Where 10 tons per acre of ground limestone were applied at Edgewood, Illinois, the average annual loss during the next ten years amounted to 790 pounds per acre. The definite data from careful investigations seem to be ample to justify the conclusion that where limestone is needed at least 2 tons per acre should be applied every 4 or 5 years. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. (See Soil Report No. 1.) Thus limestone has a positive value on some soils for the plant food which it supplies, in addition to its value in correcting soil acidity and in improving the physical condition of the soil. Ordinary lime- stone (abundant in the southern and western parts of the state) contains nearly 800 pounds of calcium per ton; while a good grade of dolomitic limestone (the more common limestone of northern Illinois) contains about 400 pounds of cal- cium and 300 pounds of magnesium per ton. Both of these elements are fur- nished in readily available form in ground dolomitic limestone. Physical Improvement of Soils In the management of most soil types, one very important thing, aside from proper fertilization, tillage, and drainage, is to keep the soil in . good physical condition, or good tilth. The constituent most important for this purpose is organic matter. Not only does it impart good tilth to the soil, but it prevents much loss by washing on rolling land, warms the soil by absorption of heat, re- tains moisture during drouth, furnishes nitrogen for the crop, aids in the libera- tion of mineral plant food, and prevents the soil from running together badly. This constituent must be supplied to the soil in every practical way, so that the amount may be maintained or even increased. It is being broken down during a large part of the year, and the nitrates produced are used for plant growth. ’Reported by Doctor Bartow and associates, of the Illinois State Water Survey. 1915] Lake County 51 This breaking down is necessary, but it is also quite necessary that the supply be maintained. The physical effect of organic matter in the soil is to produce a granulation, or mellowness, very favorable for tillage and the development of plant roots. If continuous cropping takes place, accompanied with the removal of the corn stalks and straw, the amount of organic matter is gradually diminished and a condi- tion of poor tilth will ultimately follow. In many cases this already limits the crop yields. The remedy is to increase the organic-matter content by plowing under crop residues, such as corn stalks, straw, and clover. Selling these prod- ucts from the farm, burning them, or feeding them and not returning the ma- nure, or allowing a very large part of the manure to be lost before it is returned to the land, all represent bad practice. One of the chief sources of loss of organic matter in the corn belt is the practice of burning the corn stalks. Could the farmers be made to realize how great a loss this entails, they would certainly discontinue the practice. Probably no form of organic matter acts more beneficially in producing good tilth than corn stalks. ' It is true that they decay rather slowly, but it is also true that their durability in the soil after partial decomposition is exactly what is needed in the maintenance of an adequate supply of humus. The nitrogen in a ton of cornstalks is l 1 /^ times that in a ton of manure, and a ton of dry corn stalks incorporated with the soil will ultimately furnish as much humus as 4 tons of average farm manure; but when burned, both the humus-making material and the nitrogen which these stalks contain are de- stroyed and lost to the soil. The objection is often raised that when stalks are plowed under they inter- fere very seriously in the cultivation of corn, and thus indirectly destroy a great deal of corn. If corn stalks are well cut up and then turned under to a depth of 51/2 to 6 inches when the ground is plowed in the spring, very little trouble will result. Where corn follows corn, the stalks, if not needed for feeding purposes, should be thoroly cut up with a sharp disk or stalk cutter and turned under. Likewise, the straw should be returned to the land in some practical way, either directly or as manure. Clover should be one of the crops grown in the rotation, and it should be plowed under directly or as manure instead of being sold as hay, except when manure can be brought back. It must be remembered, however, that in the feeding of hay, or straw, or corn stalks, a great destruction of organic matter takes place, so that even if the fresh manure were returned to the soil, there would still be a loss of 50 to 70 percent owing to the destruction of organic matter by the animal. If manure is allowed to lie in the farmyard for a few weeks or months, there is an additional loss which amounts to from one-third to two-thirds of the manure recovered from the animal. This is well shown by the results of an experiment conducted by the Maryland Experiment Station, where 80 tons of manure were allowed to lie for a year in the farmyard and at the end of that time but 27 tons remained, entailing a loss of about 66 percent of the manure. Most of this loss occurs within the first three or four months, when fermentation, or ‘ ‘ heating, ’ ’ is most active. Two tons of manure were exposed from April 29 to August 29, by the 52 Soil Report No. 9 L Apnl, Canadian Experiment Station at Ottawa. During these four months the organic matter was reduced from 1,938 pounds to 655 pounds. To obtain the greatest value from the manure, it should be applied to the soil as soon as possible after it is produced. It is a common practice in the corn belt to pasture the corn stalks during the winter and often rather late in the spring after the frost is out of the ground. This tramping of stock sometimes puts the soil in bad condition for working. It becomes partially puddled and will be cloddy as a result. If tramped too late in the spring, the natural agencies of freezing and thawing, and wetting and drying, with the aid of ordinary tillage, fail to produce good tilth before the crop is to be planted. Whether the crop is corn or oats, it neces- sarily suffers, and if the season is dry, much damage may result. If the field is put in corn, a poor stand is likely to follow, and if put in oats, a compact soil is formed which is unfavorable for their growth. Sometimes the soil is worked when’too wet. This also produces a partial puddling which is unfavorable to physical, chemical, and biological processes. The bad effect will be greater if cropping has reduced the organic matter below the amount necessary to maintain good tilth. UNIVERSITY OF ILLINOIS Agricultural Experiment Station SOIL REPORT NO. 10 McLEAN COUNTY SOILS By CYRIL G. HOPKINS, J. G. HOSIER, E. VAN ALSTINE, and F. W. GARRETT URBANA, ILLINOIS, MAY, 1915 State Advisory Committee on Soil Investigations Ralph Allen, Delavan A. N. Abbott, Morrison P. I. Mann, Gilman J. P. Mason, Elgin C. V. Gregory, 538 S. Clark Street, Chicago Agricultural ^Experiment Station Staff on Soil Investigations Eugene Davenport, Director Cyril G. Hopkins, Chief Soil Survey — J. G. Mosier, Chief A. F. Gustafson, Associate S. V. Holt, Associate H. W. Stewart, Associate H. C. Wheeler, Associate F. A. Fisher, Assistant F. M. W. Wascher, Assistant R. W. Dickenson, Assistant G. E. Gentle, Assistant 0. I. Ellis, Assistant H. A. deWerff, Assistant E. F. Torgerson, Assistant Soil Analysis— E. Yan Alstine, Associate J. P. Aumer, Associate W. H. Sachs, Associate Gertrude Niederman, Assistant W. R. Leighty, Assistant C. B. Clevenger, Assistant Agronomy and Chemistry Soil Experiment Fields — J. E. Whitchurch, Associate E. E. Hoskins, Associate F. C. Bauer, Associate F. W, Garrett, Assistant H. C. Gilkerson, Assistant H. F. T. Fahrnkopf, Assistant H. J. Snider, Assistant Soil Biology — A. L. Whiting, Associate W. R. Schoonover, Assistant Soils Extension — C. C, Logan, Associate INTRODUCTORY NOTE About two-thirds of Illinois lies in the corn belt, where most of the prairie lands are black or dark brown in color. In the southern third of the state, the prairie soils are largely of a gray color. This region is better known as the wheat belt, altho wheat is often grown in the corn belt and com is also a com- mon crop in the wheat belt. Moultrie county, representing the com belt; Clay county, which is fairly representative of the wheat belt; and Hardin county, which is taken to repre- sent the unglaciated area of the extreme southern part of the state, were se- lected for the first Illinois Soil Reports by counties. While these three county soil reports were sent to the Station’s entire mailing list within the state, sub- sequent reports are sent only to those on the mailing list who are residents of the county concerned, and to any one else upon request. Each county report is intended to be as nearly complete in itself as it is practicable to make it, and, even at the expense of some repetition, each will contain a general discussion of important fundamental principles in order to help the farmer and landowner understand the meaning of the soil fer- tility invoice for the lands in which he is interested. In Soil Report No. 1, “Clay County Soils,” this discussion serves in part as an introduction, while in this and other reports, it will be found in the Appendix ; but if necessary it should be read and studied in advance of the report proper. McLEAN COUNTY SOILS By CYRIL G. HOPKINS, J. G. MOSIER, E. VAN ALSTINE, and F. W. GARRETT McLean county is located in the central part of Illinois in the early Wiscon- sin glaciation. The general topography is undulating to slightly rolling, tho an area in the northwestern part of tho county along the Mackinaw river is in part badly broken. The difference in topography is due to two causes— glacial action and stream erosion. This county was covered by two ice sheets during the Glacial period. At that time snow and ice accumulated in the region of Labrador and to the west of Hudson Bay to such an amount that it pushed southward until a point was reached where the ice melted as rapidly as it advanced. In moving across the country, the ice gathered up all sorts and sizes of material, including clay, silt, sand, gravel, boulders, and even large masses of rock. Many of these were car- ried for hundreds of miles and rubbed against the surface rocks or against each other until ground into powder. When the limit of advance was reached by the melting of the ice, this material accumulated in a broad undulating ridge, or mo- raine. When the ice melted away more rapidly than the glacier advanced, the terminus of the glacier would recede and leave this material deposited somewhat uniformly over the tract, marking the area previously covered by the ice sheet. Other advances occurred which built up other moraines. The intervening intermo- rainal tracts are occupied chiefly by level, undulating, "or slightly rolling plains. The material transported by the glacier varied with the character of the rocks over which it passed. Granites, limestones, sandstones, shales, et cetera, were mixed and ground up together. This mixture of all kinds of material — boulders, clay, silt, sand, and gravel — is called boulder clay, till, glacial drift, or simply drift. The grinding and denuding power of glaciers is enormous. A mass of ice 100 feet thick exerts a pressure of 40 pounds per square inch, and this ice sheet may have been thousands of feet in thickness. The materials carried along in this mass of ice, especially the boulders and pebbles, became powerful agents for grinding and wearing away the surface over which the ice passed. Preglacial ridges and hills were rubbed down, valleys were filled with the debris, and the surface features were changed entirely. McLean county was first covered by the Illinois glacier, which did its share toward leveling the region and covering it with a deposit of boulder clay. After this a long period elapsed, during which a soil known as the Sangamon soil was formed from this glacial deposit. Then another advance occurred, known as the Iowan glacier. This glacier did not reach McLean county, but after its melt- ing the state was covered with a deposit of wind-blown loess, which buried the old soil that was formed from the Illinois glacial drift. A new soil was formed from the loess, and after a long period had elapsed another ice advance oc- curred — the early Wisconsin glacier. This covered the entire county, bringing 1 2 Soil Report No. 10 [May, with it immense quantities of the material which now covers the county to an average depth of 200 feet and in many places reaches a depth of 250 feet. The outer limit of this glaciation, known as the Shelbyville moraine, extends to the south-western corner of McLean county. (See the state soil map in Bulletin 123.) The early Wisconsin glacier advanced and receded in this county at least three different times, building up terminal moraines with each advance. The largest of these is the Bloomington moraine, which in the western two-thirds of the county is made up of a double ridge, coalescing as it reaches the eastern part. This double ridge indicates two distinct glacial advances. Another moraine, kjnown as the Cropsey ridge, occurs in the northeastern part of the county. A small spur from the Champaign moraine extends into the southeastern corner of the county, and it is likely that the extension of this was covered by the Bloom- ington moraine, which is about 100 feet higher than the area to the south. The intermorainal tracts are naturally poorly drained. They were formerly occupied by swamps, which have required much artificial drainage. Physiography The altitude of McLean county varies from 600 to about 900 feet above sea level, with an average of approximately 750 feet. The highest point, 920 feet, is on the Bloomington moraine near the center of Township 23 North, Range 4 East. The altitude of some of the points are as follows: Arrowsmith, 877 feet; Bellflower, 784 ; Bloomington, 821 ; Chenoa, 723 ; Colfax, 742 ; Cropsey, 802 ; Dan- vers, 808 ; Downs, 794 ; Ellsworth, 863 ; Funk’s Grove, 694 ; Gillum, 820 ; Gridley, 752; Hudson, 768; Lexington, 746; Leroy, 780; McLean, 708; Normal, 790; Say- brook, 786 ; Weedman, 725. The county is divided into four drainage areas : the Mackinaw in the north and northwest, the Sangamon in the east, Rooks creek, a branch of the Vermilion, in the northeast, and Sugar creek and its branches in the south and southwest. All these streams, however, flow into the Illinois river. Drainage is naturally well developed in the western half of the county. Soil Material and Soil Types The early Wisconsin glacier left extensive deposits of boulder clay over the county, but the soils as a general rule are not formed from this material. After the Wisconsin glacier, the county was again covered by a deposit of fine wind- blown material, loessial in character, varying from 2 to 7 feet in depth, and it is from this loess that the soil has generally been formed. In very small areas on some of the more rolling parts, this fine material has been removed to such an extent that the exposed boulder clay may constitute the soil material. The soils of the county are divided into four classes, as follows : (a) Upland prairie soils, rich in organic matter. These were originally covered with wild prairie grasses, the partially decayed roots of which have been the source of the organic matter. The flat prairie land contains the higher amount of this constituent because the grasses and roots grew more luxuriantly there, and the higher moisture content preserved them from complete decay. (b) Upland timber soils, including those zones along stream courses over which for a long period of time forests once extended. These soils contain much 1915 ] McLean County 3 Table 1. — Soil Types op McLean County Soil type Name of type No. | Area in square miles Area | in acres Percent of total area 926 ) 1126 \ 1120 1120.2 1128 990 ) 1190 f (a) Upland Prairie Soils (page 24) 847.38 168.69 4.04 2.42 .15 542 323.2 107 961.6 2 585.6 1 548.8 96.0 72.602 14.474 .345 .207 .012 Gravelly black clay loam Brown-gray silt loam on tight clay 934 ) 1134 f 935) 1135 5 (b) Upland Timber Soils (page 29) Yellow-gray silt loam Yellow silt loam - 73.42 27.43 46 988.8 17 555.2 6.227 2.357 1527 1526.2 1534.2 (c) Terrace Soils (page 37) Brown silt loam over gravel Brown silt loam on gravel Yellow-gray silt loam on gravel .26 1.77 .97 166.4 1 132.8 620.8 .002 .152 .083 1401 1426 1454 (d) Swamp and Bottom-Land Soils (page 38) Deep peat .13 23.88 18.06 83.2 15 283.2 11 558.4 .011 2.008 1.520 Deep brown silt loam \ I i v < '( 1 loam Total i ifiRfin 747 904 0 100.000 less organic matter, because the large roots of dead trees and the surface accu- mulations of leaves, twigs, and fallen trees were burned by forest fires or suffered almost complete decay. The timber lands are divided chiefly into two classes — the undulating and the hilly areas. (c) Terrace soils. These have been formed by deposits from flooded streams overloaded with coarse sediment at the time of the melting of the glacier. Finer deposits which were later made upon the coarse gravelly material now con- stitute the soil. (d) Swamp and bottom lands, which include the flood plains along streams and some small peaty swamp areas. Table 1 gives the area of each type of soil in the county and its percentage of the total area. It will be observed that 721/2 percent of the area consists of brown silt loam, 141/2 percent of black clay loam, and 6 percent of yellow-gray silt loam, these three types covering 93 percent of the county. The accompany- ing maps show the location and boundary lines of every type of soil in the county, even down to areas of a few acres. THE INVOICE AND INCREASE OF FERTILITY IN McLEAN COUNTY SOILS Soil Analysis In order to avoid confusion in applying in a practical way the technical information contained in this report, the results are given in the most simplified form. The composition reported for a given soil type is, as a rule, the average of many analyses, which, like most things in nature, show more or less variation ; but for all practical purposes the average is most trustworthy and sufficient. Soil Eepoet No. 10 [May, (See Bulletin 123, which reports the general soil survey of the state, together with many hundred individual analyses of soil samples representing twenty-five of the most important and most extensive soil types in the state.) The chemical analysis of a soil gives the invoice of fertility actually pres- ent in the soil strata sampled and analyzed, but, as explained in the Appendix, the rate of liberation is governed by many factors. Also, as there stated, prob- ably no agricultural fact is more generally known by farmers and landowners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field; and the fact should be repeated and emphasized that the productive power of normal soil in humid sections depends upon the stock of plant food contained in the soil and upon the rate at which it is liberated. The fact may be repeated, too, that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all plants, only one (hydrogen) from water, while seven are secured from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes) in case the amount liberated from the soil is insufficient. But even the leguminous plants (which include the clovers, peas, beans, alfalfa, and vetches), in common with other agricultural plants, secure from the soil alone six elements (phosphorus, potassium, magnesium, calcium, iron, and sulfur) and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Table A in the Appendix shows the requirements of large crops for the five most important plant-food elements which the soil must furnish. (Iron and sulfur are supplied normally from natural sources in sufficient abundance, com- pared with the amounts needed by plants, so that they are never known to limit the yield of common farm crops.) In Table 2 are reported the amounts of organic carbon ( the best measure of the organic matter) and the total amounts of the five important elements of plant food contained in 2 million pounds of the surface soil of each type, — the plowed soil of an acre about 6% inches deep. In addition, the table shows the amount of limestone present, if any; or the soil acidity as measured by the amount of limestone required to neutralize the acidity existing in the soil. The soil to the depth indicated includes at least as much as is ordinarily turned with the plow, and represents that part with which the farm manure, limestone, phosphate, or other fertilizer applied in soil improvement is incor- porated. It is the soil stratum that must be depended upon in large part to furnish the necessary plant food for the production of crops, as will be seen from the information given in the Appendix. Even a rich subsoil has little or no value if it lies beneath a worn-out surface, for the weak, shallow-rooted plants will be unable to reach the supply of plant food in the subsoil. If, however, the fertility of the surface soil is maintained at a high point, then the plants, SOIL SURVEY MAP OF McLEAN COUNTY UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION LEGEND (a) UPLAND PRAIRIE SOILS (b) UPLAND TIMBER SOILS (d) SWAMP AND BOTTOM-LAND SOILS Brown silt loam on gravel Black clay loam Gravelly black clay loam Yellow-gray silt loam (c) TERRACE SOILS Brown silt loam over gravel 1428 Deep brown silt loam Mixed loam j Deep peat Early Wisconsin Morain NORTH W EST SH EET .1 VINGSTON WOOD FOB-13 IPEOfll Cuds on fLI NOt 1 ; )l \ PJ p 1 1 6 CO O J u A HOEN& CO. BALTIMORE. 1V15] McLean County 5 with a vigorous start from the rich surface soil, can draw upon the subsurface and subsoil for a greater supply of plant food. By easy computation it will be found that the most common prairie soil of McLean county does not contain more than enough total nitrogen in the plowed soil for the production of maximum crops for forty years, while the upland timber soils contain, as an average, much less nitrogen than the prairie land. With respect to phosphorus, the condition differs only in degree, more than eight-tenths of the soil area of the county containing no more of that element than would be required for fifteen crop rotations if such yields were secured as are suggested in Table A of the Appendix. It will be seen from the same table that with the cereals about three-fourths of the phosphorus taken from the soil is deposited in the grain, while only one-fourth remains in the straw or stalks. On the other hand, the potassium is sufficient for 28 centuries if only the grain is sold, or for 450 years even if the total crops should be removed and nothing returned. The corresponding figures are about 2,000 and 500 years for magnesium, and about 9,000 and 200 years for calcium. Thus, when measured by the actual crop requirements for plant food, potassium is no more limited than magnesium and calcium ; and as explained in the Appendix, with magne- sium, and more especially with calcium, we must also consider the fact that loss by leaching is far greater than by cropping. These general statements relating to the total quantities of plant food in the plowed soil certainly emphasize the fact that the supplies of some of these necessary elements of fertility are extremely limited when measured by the needs of large crop yields for even one or two generations of people, and, with a popu- lation increasing by more than 20 percent each decade, the future needs of the Table 2. — Fertility in the Soils of McLean County, Illinois Average pounds per acre in 2 million pounds of surface soil (about 0 to 6% inches) Soil Total Total Total Total Total Total Lime- Soil type Soil type organic nitro- phos- potas- magne- cal- stone acid- No. carbon gen phorus sium 1 sium cium present ity Upland Prairie Soils 1126 Brown silt loam I 57 410 4 870 1 120 1 36 640 8 350 9 560 60 1120 Black clay loam 91 370 8 160 2 000 34 210 16 580 31 240 1 Often Rarely 1120.2 Gravelly black clay loam . 65 180 i 6 020 1 620 32 520 23 920 74 740 170 760 1128 Brown-gray silt loam on tight clay 1 47 880 ! 4 200 1 380 36 220 6 780 7 300 120 1190 Gravelly loam 1 I 32 520 | 3 040 1 000 1 35 240 8 240 6 780 1 20 Upland Timber Soils 1134 1 Yellow-gray silt loam. . I 33 670 1 2 940 ! 1 050 H [35 910 | 6 220 7 820 1 60 1135 1 Yellow silt loam 17 780 | 1 650 | 750 35 440 7 330 6 420 I l 150 Terrace Soils 1527 Brown silt loam over 1 gravel 65 180! 5 980 1 420 36 180 8 700 7 140 40 1526.2 Brown silt loam on gravel 41 930 3 770 1 080 38 430 8 050 7 480 40 1534.4 Yellow-gray silt loam on gravel 35 520 3 660 1 080 37 000 6 700 7 880 | 20 Swamp and Bottom-Land Soils 1401 Deep peat 318 850129 530 1 2 710 1 6 240: 5 610 33 460 3 930 1426 [Deep brown silt loam. . . 79 940 6 620 2 120 38 980 11 260 16 500 60 1454 |Mixed loam 65 760) 5 980 1 1 760 | 42 620 14 080 20 100 8 120 6 Soil Report No. 10 [May, people dependent upon the corn belt are likely to be far greater than the re- quirements of the past, and soil fertility and crop yields should not decrease but increase. In the production of general farm crops, McLean is now the leading county in the United States. The only rival counties for the position of greatest in agri- culture are Los Angeles, Cal., and Lancaster, Pa. The crop values reported for these counties by the latest United States census (for 1909) are as follows: 1 County Value of all crops Value of all crops except tobacco, vegetables, fruits, and nuts Los Angeles, California $14 720 884 13 059 588 $6 734 259 8 617 170 12 690 404 Lancaster, Pennsylvania McLean, Illinois 12 811 500 McLean county produced 16 million bushels of corn in 1909, while 8 million were produced in the six New England states, less than 10 million in the eleven Western states, 18 million in Maryland, 21 million in South Carolina, 39 mil- lion in Georgia, and 390 million in Illinois. And yet McLean county produced but little more than half a crop, measured by its normal climatic possibilities un- der rational systems of soil improvement. The ten-year average yield of corn for McLean county is 39 bushels per acre, according to the Statistical Reports of the Illinois State Board of Agriculture for the years 1905 to 1914. During the same ten years the average acre-yield was 78.3 bushels on the University of Illinois North Farm at Urbana, where organic manures, limestone, and phosphorus had been applied. (See records of Plots 6 and 7, Tables 3 and 4, pages 10 and 11.) Such results should induce careful study of the individual farm with its particu- lar soil type or types, in order that the best methods may be adopted for soil im- provement and preservation. The variation among the different types of soil in McLean county with re- spect to their content of important plant-food elements is very marked. Thus the richest prairie land (black clay loam) contains from three to five times as much nitrogen and twice as much phosphorus as the common upland timber soils ; and the deep peat soil contains eighteen times as much nitrogen but only one-sixth as much potassium as the yellow silt loam. The most significant facts revealed by the investigation of the McLean county soils are the lack of limestone and the low phosphorus content of the common prairie soil and of the most extensive tim- ber type, which combined cover nearly 80 percent of the entire county. And yet both of these deficiencies can be overcome at relatively small expense by the ap- plication of ground limestone and fine-ground raw rock phosphate; and, after these are provided, clover can be grown with more certainty and in greater abun- dance, and nitrogen can thus be secured from the inexhaustible supply in the air. If the clover is then returned to the soil, either directly or in farm manure, the combined effect of limestone, phosphorus, and nitrogenous organic matter, with a good rotation of crops, will in time double the yield of corn and other crops on most farms. Fortunately, some definite field experiments have already been conducted on brown silt loam, the most extensive type of soil in the early Wisconsin glaciation, as at Urbana in Champaign county, at Sibley in Ford county, and at Bloomington N O RTH EAST SHE ET LEGEND UPLAND PRAIRIE SOILS j Brown silt loam I Brown silt loam on gravel | Black clay loam | Gravelly black clay loam | Brown-gray silt loam on tight clay j Gravelly loam. UPLAND TIMBER SOILS Yellow-grav silt loam Yellow silt loam (c) TERRACE SOILS Brown silt loam over gravel Yellow-gray silt loam on gravel (d) SWAMP AND BOTTOM-LAND SOILS Deep brown silt loam Deep peat 900 Early Wisconsin Moraines 1100 Early Wisconsin I ntermorainal Areas f. COUNTY STATTOV 1915] McLean County in McLean county. Before considering in detail the individual soil types, it seems advisable to study some of the results already obtained where definite systems of soil improvement have been tried out on some of these experiment fields in different parts of central Illinois. Results of Field Experiments at Urbana A three-year rotation of corn, oats, and clover was begun on the North Farm at the University of Illinois in 1902, on three fields of typical brown silt loam prairie land which, after twenty years or more of pasturing, had grown corn in 1895, 1896, and 1897 (when careful records were kept of the yields produced), and had then been cropped with clover and grass on one field (Series 100), oats on another (Series 200), and oats, cowpeas, and corn on the third field (Series 300) until 1901. From 1902 to 1910 the three-year rotation (with cowpeas in place of clover in 1902) was followed; the average yields are recorded in Table 3. A small crop of cowpeas in 1902 and a partial crop of clover in 1904 constituted all the hay harvested during the first rotation, mammoth clover grown in 1903 having lodged so that it was plowed under. (The yields were taken by carefully weighing the clover from small representative areas, but while the differences were thus ascer- tained and properly credited temporarily to the different soil treatments, they must ultimately reappear in subsequent crop yields, and consequently the 1903 clover crop is omitted from Table 3 in computing yields and values.) The aver- age yields given represent one-third of the two small crops. From 1902 to 1907 legume cover crops (Le), such as cowpeas and clover, were seeded in the corn at the last cultivation on Plots 2, 4, 6, and 8, but the growth was small and the effect, if any, was to decrease the returns from the regular crops. Since 1907 crop residues (R) have been returned to those plots. These consist of the stalks of corn, the straw of small grains, and all legumes except alfalfa hay and the seed of clover and soybeans. On Plots 3, 5, 7, and 9, manure (M) was applied for corn at the rate of 6 tons per acre during the second rotation, and subsequently as many tons of manure have been applied as there were tons of air-dry produce harvested from the corresponding plots. Lime (L) was applied on Plots 4 to 10 at the rate per acre of 250 pounds of air-slaked lime in 1902 and 600 pounds of limestone in 1903. Subsequently 2 tons per acre of limestone was applied to these plots on Series 100 in 1911, on Series 200 in 1912, on Series 300 in 1913, and on Series 400 in 1914; also 2y 2 tons per acre on Series 500 in 1911, two more fields having been brought into rotation, as explained on page 8. Phosphorus (P) has been applied on Plots 6 to 9 at the rate of 25 pounds per acre per annum in 200 pounds of steamed bone meal ; but beginning with 1908, one half of each phosphorus plot has received 600 pounds of rock phosphate in place of the 200 pounds of bone meal, the usual practice being to apply and plow under at one time all phosphorus and potassium required for the rotation. Potassium (K=kalium) has been applied on Plots 8 and 9 at the yearly rate of 42 pounds per acre in 100 pounds of potassium sulfate, regularly in con- nection with the bone meal and rock phosphate. On Plot 10 about five times as much manure and phosphorus are applied as on the other plots, but this “extra heavy” treatment was not begun until 8 Soil Report No. 10 [May, 1906, only the usual lime, phosphorus, and potassium having been applied in previous years. The purpose in making these heavy applications is to try to determine the climatic possibilities in crop yields by removing the limitations of inadequate fertility. Series 400 and 500 were cropped in corn and oats from 1902 to 1910, but the corresponding plots were treated the same as in the three-year rotation. Beginning with 1911, the five series have been used for a combination rotation, wheat, corn, oats, and clover being rotated for five years on four fields, while alfalfa occupies the fifth field, which is then to be brought under the four-crop system to make place for alfalfa on one of the other fields for another five-year period, and so on. (See Table 4.) From 1911 to 1914 soybeans were substituted three years because of clover failure; accordingly three-fourths of the soybeans and one-fourth of the clover’ are used to compute values. Alfalfa from the 1911 seeding so nearly failed that after cutting one crop in 1912 the field was plowed and reseeded. The average yield reported for alfalfa in Table 4 is one-fourth of the combined crops of 1912, 1913, and 1914. The “higher prices” allowed for produce are $1 a bushel for wheat and soybeans, 50 cents for corn, 40 cents for oats, $10 for clover seed, and $10 a ton for hay; while the “lower prices” are 70 percent of these values, or 70 cents Plate 1. — Clover in 1913 on Urbana Field Farm Manure Applied Yield, 1.43 Tons per Acre (a) UPLAND PRAIRIE SOILS 20.2 Gravelly black clay loam Brown silt loam on gravel Brown-gray silt loam on tight clay Gravelly loam (b) UPLAND TIMBER SOILS Yellow-gray silt loam Yellow silt loam SOIL SURVEY MA UNIVERSITY OF ILLINOIS AGli SOUTHWEST SHEET VP7//A rtTT COUNTY (d) SWAMP AND BOTTOM-LAND SOILS (c) TERRACE SOILS 1113 — ss — ^rr 92 VW —Sift? r y 1' Brown silt loam over gravel Brown silt loam on gravel Yellow-gray silt loam Deep brown silt loam Mixed loam Deep peat 900 Early Wisconsin Moraines coo Early Wisconsin I nter'morainal Areas Scale o M* Vz i Mile s OF McLEAN COUNTY CULTURAL EXPERIMENT STATION 1915 ] McLean County 9 for wheat and soybeans, 35 cents for corn, 28 cents for oats, $7 for clover seed, and $7 a ton for hay. The double set of values is used to emphasize the fact that a given practice may or may not be profitable, depending upon the prices of farm produce. The lower prices are conservative, and unless otherwise stated, they are the values regularly used in the discussion of results. It should be understood that the increase produced by manures and fertilizers requires in- creased expense for binding twine, shocking, stacking, baling, threshing, haul- ing, storing, and marketing. Measured by the average Illinois prices for the past ten years, these lower values are high enough for farm crops standing in the field ready for the harvest. The cost of limestone delivered at the farmers’ railroad station in carload lots averages about $1.25 per ton. Steamed bone meal in carloads costs from $25 to $30 per ton. Fine-ground raw rock phosphate containing from 260 to 280 pounds of phosphorus, or as much as the bone meal contains, ton for ton, but in less readily available form, usually costs the farmer from $6.50 to $7.50 per ton in carloads. (Acid phosphate carrying half as much phosphorus, but in soluble form, commonly costs from $15 to $17 per ton delivered in carload lots in central Illinois.) Under normal conditions potassium costs about 6 cents a pound, or $2.50 per acre per annum for the amount applied in these experi- ments, the same as the cost of 200 pounds of steamed bone meal at $25 per ton. Plate 2. — Clover in 1913 on Urbana Field Farm Manure, Limestone, and Phosphorus Applied Yield, 2.90 Tons per Acre [May, SOUTHEAST SHEET { ) i 1915 ] McLean County 11 Table 4. — Yields per Acre, Four-year Averages, 1911-19 Urbana Field Brown Silt Loam Prairie; Early Wisconsin Gl vtion Serial plot No. Soil treat- ment Wheat, bu. Corn, bu. Oats, bu. Soybeans-3, tons (bu.) 1 -iver-1, tons 'bu.) 1“ 07777777 . 18.3 50.8 39.8 L6C* 1.70 2 R 19.7 53.8 40.6 ( 2 °.D 1 ( -74) 3 M 20.3 59.3 48.8 1.60 7 1.43 4 EL 22.3 55.7 42.8 (19.0) (1.03) 5 ML 24.9 58.6 51.6 1.66 1.94 6~~ rlp.7 77 37.4 “ 62.2 58.7 (21.0)^7 (2.48) 7 MLP .... 36.6 63.8 60.9 1.88yA 2.90 8 RLPIC . . . 36.1 58.9 59.1 ( 22 . 2 ) (1.41) 9 MLPK. . 35.3 1 59.6 65.1 2.09 . 2.72 10 MxLPx . . 43.5 | 55.7 67.2 2.14 2.94 To these cash investments must he added the expense od ing the materials. This will vary with the distance from road station, with the character of roads, and with the farnl diate requirements of other lines of farm work. It is the pa} such materials in advance to be shipped when specified, so ceived and applied when other farm work is not too press| when the roads are likely to be in good condition. The practice of seeding legume cover crops in the cornfie d at the last culti- vation where oats are to follow the next year has not been found profitable, as a rule, on good corn-belt soil; but the returning of the crop residues to the land may maintain the nitrogen and organic matter equally as well as the hauling and spreading of farm manure, — and this makes possible permanent systems of farm- ing on grain farms as well as on live-stock farms, provided, of course, that other essentials are supplied. (Clover with oats or wheat, as a cove-crop to be plowed under for corn, often gives good results.) At the lower prices for produce, manure (6 tons per acre) was wbTfciT$L05 a ton as an average for the first three years it was applied (1905 to 1907). The' next roiation the average application of 10.21 tons per acre on Plot 3 was worth $10.09, or 99 cents a ton. The last four years, 1911 to 1914, the average amount applied (once for the rotation) on Plot 3 was 11.35 tons per acre, worth $6.42, or 57 cents a ton, as measured by its effect on the wheat, corn, oats, soybeans, and clover. Thus, as an average of the ten years’ results, the farm manure ap- plied to Plot 3 has been worth 84 cents a ton on common corn-belt prairie soil, with a good crop rotation including legumes. During the last rotation period moisture has been the limiting factor to such an extent as probably to lessen the effect of the manure. Aside from the crop residues and manure, each addition affords a duplicate test as to its effect. Thus the effect of limestone is ascertained by comparing Plots 4 and 5, not with Plot 1, but with Plots 2 and 3 ; and the effect of phosphorus is ascertained by comparing Plots 6 and 7 with Plots 4 and 5, respectively. As a general average, the plots receiving limestone have produced $1.22 an acre a year more than those without limestone, and this corresponds to more than $6 a ton for all of the limestone applied; but the amounts used before 1911 were so small and the results vary so greatly with the different plots, crops, and seasons that final conclusions cannot be drawn until further data are secured, 12 Soil Eeport No. 10 \May, nd highest the first 2-ton application* having been completed only for 1914. However, all comparisons by rotation riods show some increase for limestone, varying from 82 cents on three acre- Plot 4) during the first rotation, to $8.75 on five acres (Plot j) as an avera',e of the last four years; and the need of limestone for best 'rofits seems well established. of duplicate trials (Plots 6 and 7), phosphorus in bone meal alued at $1.92 per acre per annum for the first three years n 'xt three; and the corresponding subsequent average in- 1 and raw phosphate (one-half plot of each) were $5.12 for d $5.36 for the last four years, 1911 to 1914. The annual phosphorus is $2.80 in bone meal at $28 a ton, or $2.10 for ton. ed at an estimated cost of $2.50 an acre a year, seemed to ses, as an average, during the first and second rotations; se increases have been slightly more than lost in reduced et result to date being an average loss of $2.53 per acre g the cost of the potassium. hs nearly paid its cost during the first rotation, and has sub- nnual cost and about 100 percent net profit ; while potassium, a general average, has produced no effect, and money spent for its applica- Plate 3. — Clover on Urbana Field, South Farm Crop Eesidues Plowed Under 1915 ] McLean County 13 tion has been lost. These field results are in harmony with what might well be expected on land naturally containing in the plowed soil of an acre only about 1,200 pounds of phosphorus and more than 36,000 pounds of potassium. The total value of five average crops harvested from the untreated land dur- ing the last four years is $65. Where limestone and phosphorus have been used together with organic manures (either crop residues or farm manure), the cor- responding value exceeds $98. Thus 200 acres of the properly treated land would produce as much in crops and in value as 300 acres of the untreated land. The excessive applications on Plot 10 have usually produced rank growth of straw and stalk, with the result that oats have often lodged badly and corn has frequently suffered from drouth and eared poorly. Wheat, however, has as an average yielded best on this plot. The largest yield of corn on Plot 10 was 118 bushels per acre in 1907. As an average of the results secured during the twelve years 1903 to 1914, on the University South Farm where fine-ground raw rock phosphate is applied at the rate of 500 pounds per acre per annum on the typical brown silt loam prairie soil, the return for each ton of phosphate 1 used has been $13.57 on Series Plate 4. — Clover on Urbana Field, South Farm Fine-Ground Book Phosphate Plowed Under with Crop ‘During the first four years, Series 100 received only 1,500 pounds per acre of phos- phate, and both series received also % ton per acre of limestone, the effect of which probably would be slight, as may be judged from the data secured later and reported herein. 14 Soil Report No. 10 [May, 100 and $12.07 on Series 200, with the “lower prices” allowed for produce, the rotation being wheat, corn, oats, and clover (or soybeans). This gives an average return of $12.82 for each ton of phosphate applied. Averages for each rotation period show the following value of increase per ton of phosphate used : Lower Higher prices prices First rotation, 1903 to 1906 $ 8.26 $11.80 Second rotation, 1907 to 1910 11.33 16.19 Third rotation, 1911 to 1914 18.88 26.97 Thus the rock phosphate paid back more than its cost during the first rota- tion, more than iy 2 times its cost during the second rotation, and more than 21/2 times its cost during the third rotation period. One ton of fine-ground rock phosphate costs about the same as 500 pounds of steamed bone meal. Altho in less readily available form, the rock phosphate con- tains as much phosphorus, ton for ton, as the bone meal ; and, when equal money values are applied in connection with liberal amounts of decaying organic matter, the natural rock may soon give as good results as the bone, — and, by supplying about four times as much phosphorus, the rock provides for greater durability. The results just given represent averages covering the residue system and the live-stock system, both of which are represented in this crop rotation on the South Farm. Ground limestone at the rate of 8 tons per acre was applied to the east half of these series of plots (excepting the check plots, which receive only residues or manure), beginning in 1910 on Series 200 and in 1911 on Series 100. Subsequent applications are made of 2 tons per acre each four years, beginning in 1914 on Series 200 and in 1915 on Series 100. As an average of results from both series, the crop values were increased during the third rotation, 1911-1914, as follows: Residue System Live-Stock System Lower Higher Lower Higher prices prices prices prices Gain for phosphate $18.80 $26.86 $18.96 $27.09 Gain for limestone 2.31 3.30 2.55 3.64 Detailed records of these investigations are given in Tables 5 and 6, the data being reported by half-plots after 1910-1911. (Series 300 and 400, which are also used in this rotation, are located in part upon black clay loam and a heavy phase of brown silt loam. See discussion under “Black Clay Loam,” page 26.) Results of Experiments on Sibley Field Table 7 gives the results obtained during twelve years from the Sibley soil experiment field located in Ford county on the typical brown silt loam prairie of the Illinois corn belt. Previous to 1902 this land had been cropped with corn and oats for many years under a system of tenant farming, and the soil had become somewhat defi- cient in active organic matter. While phosphorus was the limiting element of plant food, the supply of nitrogen becoming available annually was but little in excess of the phosphorus, as is well shown by the corn yields for 1903, when the addition of phosphorus produced an increase of 8 bushels, nitrogen produced no increase, but nitrogen and phosphorus increased the yield by 15 bushels. After six years of additional cropping, however, nitrogen appeared to be- 1915] McLean County 15 is .3 O fH 1-5 P M * £.2 O Fh iJ P £3 O 05 jgg > ^ 05 O O ' : ^ ^ rH . c i O CO rji < t> GO CO CO OO 00 CD CD tJH 03 IO Ni^oeoco co 03 co co ■ 00 05 IO CO 05 CO 03 CM H 03 03 < IO O H IO IO CO i t- 00 CD o CD CO l>CDCDNl- CO O O CD IO CO CO 03 CM CO CO IO 05 CO 03 CD 05 I - o 05 03* rH IO CD ^ IO IO CD I 00 b- CO tH CO i CO 03* rH id 05 l tH rfH CO CO 03 IO O IO CD © rH CO © GO 03 CO* l>»* 05* 05* O § ^ s ~ 03 00 O O O 05 " CD W 03* 03* O 03 rH 03 03 0 * ^ m P Pi 03 ,Q 5 bo o fl 42 o 45 a. pc w « PuPh ►4 H SS ~ S o o * CD I- b- b- 16 Soil Report No. 10 [May, Eh *| I _P> 1 h i H ft I mm S 5; « S3 ® £ gss's'ss It 53S33I ss 5000 ^; ' ggggg iss's'ss IL 4 .^3.58 MORONI ^SSS! SSS“2” If Is C5 N 05 CO ^ O "ESSSS !§ss i in h o o N 6 LO CO CO 00 LO iO CO ^ CO CO rH CO ©3 L- CO g^SSS 1 5 ca CO co oa in II . lO O LO Cl co ca co to cj I Ill'll sssssrg ’i f0 . °°. °. °°. l ". II iSIHS mm mM miss msss 1915 ] McLean County 17 come the most limiting element, the increase in the corn in 1907 being 9 bushels from nitrogen and only 5 bushels from phosphorus, while both together pro- duced an increase of 33 bushels. By comparing the corn yields for the four years 1902, 1903, 1906, and 1907, it will be seen that the untreated land appar- ently grew less productive, whereas, on land receiving both phosphorus and nitrogen, the yield appreciably increased, so that in 1907, when the untreated rotated land produced only 34 bushels of corn per acre, a yield of 72 bushels (more than twice as much) was produced where lime, nitrogen, and phosphorus had been applied, altho the two plots produced exactly the same yield (57.3 bushels) in 1902. Table 7. — Crop Yields in Soil Experiments, Sibley Field Brown silt loam prairie ; 1 early Wisconsin glaciation Corn Corn 1902 ( 1903 Oats 1904 ! Wheat Corn 1905 1906 1 Corn 1907 Oats 1908 Wheat 1 Corn 1909 1910 Corn 1911 Oats 1912 Wheat 1913 Plot Soil treatment applied Bushels per acre 101 None 57.3 50.4 74.4 29.5 36.7 33.9 25.9 25.3 26.6 20.7 84.4 5.5 102 Lime 60.0 54.0 74.7 31.7 39.2 38.9 24.7 28.8 34.0 22.2 85.6 6.8 103 Lime, nitro 60.0 54.3 ~77\5 32.8 4L7 48.1 "36(3 19(0 297) "22(4 25.3 18.3 104 Lime, phos 61.3 62.3 92.5 36.3 44.8 43.5 25.6 32.2 52.0 31.6 92.3 10.7 105 Lime, potas 56.0 49.9 74.4 30.2 37.5 34.9 22.2 23.2 34.2 21.6 83.1 7.5 106 Lime, nitro., phos. . . 57.3 "69Y 88.4 45.2 "68(5 72.3 "4576 “33X" "5576 "35(3 42.2 24.7 107 Lime, nitro., potas.. 53.3 51.4 75.9 37.7 39.7 51.1 42.2 25.8 46.2 20.1 55.6 19.2 108 Lime, phos., potas.. . 58.7 60.9 80.0 39.8 41.5 39.8 27.2 28.5 43.0 31.8 79.7 11.8 109 Lime, nitro., phos., potas 58.7' 65.9 82.5 48.0 69.5 80.1 52.8 35.0 58.0 35.7 57.2 24.5 110 Nitro., phos., potas.. 60.0, 60.1 85.0 48.5 63.3 72.3 44.1 30.8 64.4 31.5 54.1 18.0 Increase : Bushels per Acre For nitrogen .0 .3 2.8 1.1 2.5 9.2; 11.6 -9.8 -5.0, .2 -60.3 11.5 For phosphorus 1.3 8.3 17.8 4.6 5.6 4.6 .9 3.4 18.0, 9.4 6.7 3.9 For potassium -4.0, -4.1 -.3 -1.5 -1.7 -4.0 ! -2.5 -5.6 .2, -.6 -2.5 .7 For nitro., phos. over phos -4.o : 6.8 -4.1 8.9 23.7 28.8 20.0 1.1 3.6, 3.7 -50.1 14.0 For phos., nitro. over nitro -2.7 14.8 10.9 12.4 24.8 24.2 9.3 14.3 20.6 12.9 10.9 6.4 For potas., nitro., phos. over nitro., phos 1.4 -3.2 -5.9 2.8 1.0 7.8 7.2 1.7 | 2.4 .4 15.0 -.2 Value of Crops per Acre in Twelve Years Plot Soil treatment applied Total value of twelve crops Lower Higher prices prices 101 $172.89 186.51 $246.98 266.45 102 103 Lime, nitrogen ""177.44 253.49 104 Lime, phosphorus 217.78 311.11 105 Lime, potassium 167.32 239.03 106 Lime, nitrogen, phosphorus 246.91 352.73 107 Lime, nitrogen, potassium 198.16 283.08 108 Lime, phosphorus, potassium 204.90 292.71 109 Lime, nitrogen, phosphorus, potassium 257.91 368.45 110 Nitrogen, phosphorus, potassium 242.47 346.38 Value of Increase per Acre in Twelve Years For nitrogen For phosphorus For nitrogen and phosphorus over phosphorus $ 9.07 31.27 29.13 $12.96 44.66 41.62 For ‘phosphorus and nitrogen over nitrogen 69.47 99.24 For potassium, nitrogen, and phosphorus over nitrogen and phosphorus 11.00 15.72 18 Soil Report No. 10 [May, Even in the unfavorable season of 1910 the yield of the highest producing plot exceeded the yield of the same plot in 1902, while the untreated land pro- duced less than half as much as it produced in 1902. The prolonged drouth of 1911 resulted in almost a failure of the corn crop, but nevertheless the effect of soil treatment was seen. Phosphorus appeared to be the first limiting element again in 1909, 1910. and 1911 ; while the lodging of oats, especially on the nitro- gen plots, in the exceptionally favorable season of 1912, produced very irregular results. In 1913, wheat averaged 6.6 bushels without nitrogen or phosphorus (Plots 101, 102, 105) and 22.4 bushels where both nitrogen and phosphorus were added (Plots 106, 109, 110). In the lower part of Table 7 are shown the total values per acre of the twelve crops from each of the ten different plots, the amounts varying from $167.32 to $257.91, with corn valued at 35 cents a bushel, oats at 28 cents, and wheat at 70 cents. Phosphorus without nitrogen has produced $31.27 in addition to the increase by lime, but with nitrogen it has produced $69.47 above the crop values where only lime and nitrogen have been used. The results show that in 26 cases out of 48 the addition of potassium has decreased the crop yields. Even when applied in addition to phosphorus, and with no effort to liberate potassium from the soil by adding organic matter, potassium has produced no increase in crop values as an average of the results from Plots 108 and 109. By comparing Plots 101 and 102, and also 109 and 110, it is seen that lime has produced an average increase of $14.53, or $1.21 an acre a year. This in- crease on these plots is practically the same as at Urbana, and it suggests that the time is here when limestone must be applied to some of these brown silt loam soils. While nitrogen, on the whole, has produced an appreciable increase, espe- cially on those plots to which phosphorus has also been added, it has cost, in com- mercial form, so much above the value of the increase produced that the only conclusion to be drawn, if we are to utilize this fact to advantage, is that the nitrogen must be secured from the air. Results of Experiments on Bloomington Field Space is taken to insert Tables 8 and 9, giving all results thus far obtained from the Bloomington soil experiment field, which is also located on the brown silt loam prairie soil of the Illinois corn belt. This field is a part of the S. Noble King farm. The general results of the thirteen years’ work tell much the same story as those from the Sibley field. The rotations have differed since 1905 by the use of clover and the discontinuing of the use of commercial nitrogen, — in conse- quence of which phosphorus without commercial nitrogen, on the Bloomington field, has produced an even larger increase ($99.85) than has been produced by phosphorus and nitrogen over nitrogen on the Sibley field ($69.47). It should be stated that a draw runs near Plot 110 on the Bloomington field, that the crops on that plot are sometimes damaged by overflow or imperfect drainage, and that Plot 101, occupies the lowest ground on the opposite side of the field. In part because of these irregularities and in part because only one small application has been made, no conclusions can be drawn in regard to lime. Otherwise all results reported in Table 8 are considered reliable. They not only 1915] McLean County 19 furnish much information in themselves, but they also offer instructive com- parison with the Sibley field. Wherever nitrogen has been provided, either by direct application or by the use of legume crops, the addition of the element phosphorus has produced very marked increases, the average yearly increase for the Bloomington field being worth $7.02 an acre. This is $4.52 above the cost of the phosphorus in 200 pounds of steamed bone meal, the form in which it is applied on the Sibley and the Bloomington fields. On the other hand, the use of phosphorus without nitrogen will not maintain the fertility of the soil (see Plots 104 and 106, Sibley field). As the only practical and profitable method of supplying nitrogen, a liberal use of clover or other legumes is suggested, the legume to be plowed under either directly or as manure, preferably in connection with the phosphorus applied, especially if raw rock phosphate is used. Prom the soil of the best treated plots on the Bloomington field, 180 pounds per acre of phosphorus, as an average, has been removed in the thirteen crops. This is equal to 15 percent of the total phosphorus contained in the surface soil of an acre of the untreated land. In other words, if such crops could be grown for eight;, years, they would require as much phosphorus as the total supply in the ordinary plowed soil. The results plainly show, however, that without the addition of phosphorus such crops cannot be grown year after year. Where no phosphorus has been applied, the crops have removed only 120 pounds of phosphorus in the thirteen years, which is equivalent to only 10 percent of the total amount (1,200 pounds) present in the surface soil at the beginning of the experiment in 1902. The total phosphorus applied from 1902 to 1914, as an average of all plots where it has been used, has amounted to 325 pounds per acre and has cost $32.50. 1 This has paid back $97.20, or 300 percent on the invest- Plate 5. — Corn in 1912 on Bloomington Field On Left, Residues, Lime, and Potassium: Yield, 58.9 Bushels On Right, Residues, Lime, and Phosphorus: Yield, 86.1 Bushels 1 This is based on $25 a ton for steamed bone meal, but in recent years the price has been advanced generally to nearly $30. 20 Soil Report No. 10 [May, It II I1|S1S|333|S3 31 37.5 44.1 32.1 ~50A~ 34.5 J9^ is 55.2 47.9 ass|ass S3 33 Ife 53 131 rtH O §3 1.56 | 1.09 ga g5 ?§ 3l|31i 111 si S3' 131 m is iass|sss ^ O S3| cc 30.8 , 28.8 io oq cq Snn 05 WOO taa io 10 Si SSI Mi S3 05 CO 8§ lOO^ m 13 (50 O m 31 23333^ CO CO Oi CO CO h- ag^g* 2 s - !f ar^a ■ 1.2 19.0 1.0 -3.2 14.6 9.5 -.12 1.07 -.07 -1.65 -.46 | .00 10.4 4.4 11.7 20.4 l 1.0 O C5 N CO W N ' -.8 12.7 -3.9 4.6 18.1 3.3 ^■aaa 1915 ] McLean County 21 Table 9. — Value op Crops per Acre in Thirteen Years, Bloomington Field Plot Soil treatment applied Total \ thirtee: Lower prices ralue of n crops Higher prices 101 102 $186.83 186.76 $266.90 266.80 103 104 105 193.83 286.61 190.53 276.90 409.45 272.19 Lime, phosphorus Lime, potassium 106 107 108 Lime, residues, phosphorus 285.03 191.10 294.91 407.19 273.00 421.31 Lime, residues, potassium Lime, phosphorus, potassium 109 110 Lime, residues, phosphorus, potassium Residues, phosphorus, potassium 284.47 259.10 406.39 370.15 Value of Increase per Acre in Thirteen Years For re For pi For re For pi For pi $ 7.07 99.85 -1.58 91.20 -.56 $ 10.10 142.65 -2.26 130.29 -.80 losphorus sidues and phosphorus over phosphorus vosphorus and residues over residues itassium, residues, and phosphorus over residues and phosphorus. . . . ment ; whereas potassium, used in the same number of tests and at the same cost, has paid back only $2.20 per acre in the thirteen years, or less than 7 percent of its cost. Are not these results to be expected from the composition of such soil and the requirements of crops? (See Table 2 ; also Table A in the Appendix.) Nitrogen was applied to this field, in commercial form only, from 1902 to 1905 ; but clover was grown in 1906 and 1910, and a cover crop of cowpeas after the clover in 1906. The cowpeas were plowed under on all plots, and the 1910 clover (except the seed) was plowed under on five plots (103, 106, 107, 109, and 110). Straw and corn stalks have also been returned to these plots in recent years. The effect of returning these residues to the soil has been appreciable since 1910 (an average increase on Plots 106 and 109 of 4.5 bushels of wheat, 5.4 bushels of corn, and 4.3 bushels of oats) and probably will be more marked on subse- quent crops. Indeed, the large crops of corn, oats, and wheat grown on Plots 104 and 108 during the thirteen years have drawn their nitrogen very largely , from the natural supply in the organic matter of the soil. The roots and stubble of clover contain no more nitrogen than the entire plant takes from the soil alone, but they decay rapidly in contact with the soil and probably hasten the decomposition of the soil humus and the consequent liberation of the soil nitro- gen. But of course there is a limit to the reserve stock of humus and nitrogen remaining in the soil, and the future years will undoubtedly witness a gradually increasing difference between Plots 104 and 106, and between Plots 108 and 109, in the yields of grain crops. Plate 6 shows graphically the relative values of the thirteen crops for the eight comparable plots, Nos. 102 to 109. The cost of the phosphorus is indicated by that part of the diagram above the short crossbars. It should be kept in mind that no value is assigned to clover plowed under except as it reappears in the increase of subsequent crops. Plots 106 and 109 are heavily handicapped because of the clover failure on those plots in 1906 and the poor yield of clover seed in 1910, whereas Plots 104 and 108 produced a fair crop in 1906 and a very Soil Report No. 10 [May, 22 large crop in 1910. Plot 106, which receives the most practical treatment for permanent agriculture (RLP), has produced a total value in thirteen years only $1.58 below that from Plot 104 (LP). (See also table on last page of cover.) The Subsurface and Subsoil In Tables 10 and 11 are recorded the amounts of plant food in the subsur- face and the subsoil of the different types of soil in McLean county, but it should be remembered that these supplies are of little value unless the top soil is kept rich. Probably the most important information contained in these tables is that the most common prairie soil and the upland timber soils are from slightly to strongly acid in the subsurface and sometimes contain no limestone in the subsoil. This fact emphasizes the importance of having plenty of limestone in the surface soil to neutralize the acid moisture which rises from the lower strata by capillary action during times of partial drouth, which are critical periods in the life of such plants as clover. While the common brown silt loam prairie is usually slightly acid, the upland timber soils are, as a rule, more distinctly in need of $186.76 $193.83 $286.61 $190.53 $285.03 $191.10 $294.91 $284.47 Plate 6. — Crop Values for Thirteen Years, Bloomington Experiment Field (R=residues; P=phosphorus ; K=potassium, or kalium) 1915 J McLean County 23 limestone, and as already explained, they are also more deficient in organic mat- ter and nitrogen than the prairie soils, and thus more in need of growing clover. Table 10. — Fertility in the Soils of McLean County, Illinois Average pounds per acre in 4 million pounds of subsurface soil (about 6% to 20 inches) Soil Total Total Total Total Total Total Lime- Soil type Soil type organic nitro- phos- potas- magne- cal- stone acid- No. carbon gen phorus sium sium cium present ity Upland Prairie Soils 1126 Brown silt loam 74 530 6 660 1 870 73 230 19 520 17 850 110 1120 Black clay loam 91 ISO 8 130 3 150 70 760 33 150 57 190 Often Barely 1120.2 Gravelly black clay loam 65 200 6 240 2 600 67 880 46 640 106 200 252 200 1128 Brown-gray silt loam oe tight clay 27 720 3 200 2 160 78 960 17 640 12 040 880 1190 Gravelly loam ... 58 160 5 600 2 000 75 840 20 400 15 080 40 Upland Timber Soils 1134 Yellow-gray silt loam . . . 24 490 2 710 1 490 74 230 16 390 13 980 2 350 1135 Yellow silt loam ...... 15 280 2 020 1 540 |72 000 24 620 14 620 | 3 660 Terrace Soils Brown silt loam over gravel 68 200 6 320; 2 160 75 880 18 960 12 840 80 Brown silt loam on gravel 55 320 5 160 1 640 83 780 22 600 14 340 100 Yellow-gray silt loam on gravel 26 800 3 000 1 560 73 800 19 440 17 240 80 Swamp and Bottom-Land Soils 1401 Deep peat 608 090 52 420 4 610 14 160 11 080 63 270 Barely Often 1426 Deep brown silt loam . . . 144 760 11 520 3 320 69 280 22 080 34 920 1 300 1454 Mixed loam 112 560 11 080 3 080 83 320 28 960 37 000 3 160 Table 11. — Fertility in the Soils of McLean County, Illinois Average pounds per acre in 6 million pounds of subsoil (about 20 to 40 inches) Soil l'otal Total Total Total Total Total Lime- Soil type Soil type organic nitro- phos- potas- magne- cal- stone acid- No. carbon gen phorus sium sium cium present ity Upland Prairie Soils 1126 Brown silt loam 32 310 3 620 2 350 114 870 48 600 46 360 Barely Often 1120 Black clay loam 35 480 3 450 3 410 111 560 58 820 80 450 Often Barely 1120.2 Gravelly black clay loam 47 760 4 140 3 120 104 220 54 540 119 520 279 300 1128 Brown-gray silt loam on tight clay 21 900 3 120 3 540 120 600 36 240 19 500 840 1190 Gravelly loam 57 060 5 460 2 040 110 040 32 100 19 560 60 Upland Timber Soils 1134 Yellow-gray silt loam... 21 380 2 840 4 040 114 270142 060 31 590 1 1 Often 1135 Yellow silt loam 20 250 2 580 3 000 110 82o| 58 650 60 510 1 | Often Terrace Soils 1527 Brown silt loam over gravel 36 120 3 840 2 520 106 800 39 540 22 320 420 1526.2 Brown silt loam on gravel 42 690 4 470 2 130 113 040 37 380 24 300 Often 1534.4 Yellow-gray silt loam on gravel 28 800 3 180 2 700 103 620 30 360 27 180 420 Swamp and Bottom-Land Soils 1401 Deep peat 752 400 55 050 4 650 38 010 20 490 71 910 30 1426 Deep brown silt loam .... 86 880 5 640 3 180 108 600 27 720 47 220 120 1454 Mixed loam 101 280 9 900 3 120 123 900 43 320 49 200 60 24 Soil Report No. 10 [May, INDIVIDUAL SOIL TYPES (a) Upland Prairie Soils The upland prairie soils of McLean county occupy 1,022.68 square miles, or 87.64 percent of the entire area of the county. They are black or brown in color, owing to their large content of organic matter. The accumulation of organic matter in the prairie soils is due to the growth of prairie grasses whose network of roots was protected from complete decay by imperfect aeration due to the covering of fine soil material and the moisture it contained. On the native prairies, the tops of these grasses were usually burned or became almost completely decayed. From a sample of virgin sod of “blue stem,” one of the most common prairie grasses, it has been determined that an acre of this soil to a depth of seven inches contained 13.5 tons of roots. Many of these roots died each year and by partial decay formed the humus of these dark prairie soils. Brown Silt Loam (1126, or 926 on moraines ) Brown silt loam is the most important as well as the most extensive soil type in the county. It covers an area of 847.38 square miles (542,323 acres), or 72.6 percent of the entire county. This type occupies the slightly undulating to rolling areas of the prairie land, much of which is well surface-drained, while many areas need artificial drainage. The morainal areas are sometimes sufficiently rolling to require con- siderable care in preventing erosion. Altho brown silt loam is normally a prairie soil, yet in some limited areas forests have recently invaded the dark soil. These forests consist quite largely of black walnut, wild cherry, hackberry, ash, hard maple, and elm. A black-walnut soil is recognized generally by farmers as being one of the best timber soils because of the fact that it still contains a large amount of organic matter, characteristic of prairie soils. After the growth of several generations of trees, the organic matter would become so reduced that the soil would then be classed as a timber type. The surface soil, 0 to 6% inches, is a brown silt loam, varying on the one hand to black as it grades into black clay loam (1120), and on the other hand to grayish brown or yellowish brown as it grades into the timber type, yellow-gray silt loam (1134 or 934). The physical composition varies to some extent, but it is normally a silt loam, containing from 65 to 80 percent of silt, together with some sand, and from 10 to 15 percent of clay. The amount of clay increases as the type approaches the black clay loam (1120), and becomes greatest in the level, poorly drained areas. The amount of sand varies from 10 to 20 percent. The organic-matter content varies from 3.5 to 6.6 percent, with an average of 4.9 percent, or 49 tons per acre. The amount is less in the more rolling areas than in the low and poorly drained parts, owing to the fact not only that less vegetation grows on the drier, rolling areas, but that when incorporated with the soil much of it is removed by erosion and undergoes greater decomposition be- cause of better aeration and less moisture. Where the type passes into the yel- low-gray silt loam (1134 or 934), the organic-matter content becomes less, while in the low, swampy tracts where the grasses grew more luxuriantly and their 1915] McLean Count? 25 roots were more abundant, the large moisture content furnished conditions more favorable for the preservation of organic matter. The natural subsurface is represented by a stratum varying from 6 to 16 inches in thickness, being thinner on the more rolling areas, while decidedly thicker and darker on the more level areas. Its physical composition varies in the same way as that of the surface soil, but it usually contains a slightly larger amount of clay, especially as it approaches the black clay loam type (1120). Both color and depth vary with the topography, the stratum being lighter in color as well as shallower on the more rolling areas and where the type grades into yellow-gray and yellow silt loam (1134 or 1135). The amount of organic matter varies with depth, but the average for this stratum (which is twice the thickness of the surface soil as it is sampled) is 3.2 percent, or 64 tons per acre. The natural subsoil begins at 12 to 23 inches, and extends to an indefinite depth, but is sampled to 40 inches. It varies with the topography both in color and texture, and becomes slightly coarser with depth. It consists of a yellow or drabbish mottled yellow, clayey silt or silty clay, plastic when wet. Where the drainage has been good, it is of a bright to a pale yellow color. With poor drain- age it approaches a drab or olive color with pale yellow mottlings or a yellow color with mottlings of drab. Each of the above strata is pervious to water, so that drainage takes place with little difficulty. A phase of brown silt loam has been recognized in this county where, be- cause of the removal of part of the fine loessial material by erosion, the glacial drift is encountered less than 30 inches from the surface. If the drift is quite compact, as is occasionally the case, this gives rise to a somewhat inferior subsoil, owing to its less pervious character. This condition, however, does not occur very generally nor over large areas, since most of the drift is pervious and some is quite gravelly. This phase is found mostly in Township 23 North, Range 6 East. In the northeastern part of the county a slightly sandy phase of the type is found, but it is not sufficiently sandy to be classed as a loam. Small areas of sandy and gravelly loam, too small to be shown on the map, are common in the most rolling part of the morainal regions. An abnormal phase of brown silt loam about 30 acres in extent is found in the northeast forty of Section 11, Township 22 North, Range 5 East. In spots this varies a great deal from the true type, being a sandy peat in some places, a marly peat in others, and in still others containing large amounts of brown iron oxid. While the common brown silt loam is in fair physical condition, yet continu- ous cropping to corn, or corn and oats, with the burning of the stalks, is de- stroying the tilth ; the soil is becoming more difficult to work ; it runs together more ; and aeration, granulation, and absorption of moisture do not take place as readily as formerly. This condition of poor tilth may become serious if the pres- ent methods of management continue ; it is already one of the factors that limit the crop yields. The remedy is to increase the organic-matter content by plow- ing under farm manure and crop residues, such as corn stalks, straw, and clover. The addition of fresh organic matter is not only of great value in improving the physical condition of this type of soil, but it is of even greater importance because of its nitrogen content and because of its power, as it decays, to liberate potassium from the inexhaustible supply in the soil, and phosphorus from the phosphate contained in or applied to the soil. Soil Reiokt No. 10 [May, 26 For permanent, profitable systems of farming on brown silt loam, phos- phorus should be applied liberally, and sufficient organic matter should be pro- vided to furnish the necessary amount of nitrogen. On the ordinary type, lime- stone is already becoming deficient. An application of two tons of limestone and one-half ton of fine-ground rock phosphate per acre every four years, with the return to the soil of all manure made from a rotation of corn, corn, oats, and clover, will maintain the fertility of this type, altho heavier applications of phos- phate may well be made during the first two or three rotations. If grain farming is practiced, the rotation may be wheat, corn, oats, and clover, with an extra seed- ing of clover as a cover crop in the wheat, to be plowed under late in the fall or in the following spring for corn ; and most of the crop residues, with all clover except the seed, should also be plowed under. In either system, alfalfa may be grown on a fifth field and moved every five years, the hay being fed or sold. In live-stock farming the regular rotation may be extended to five or six years by seeding both timothy and clover with the oats, and pasturing one or two years. Alsike and sweet clover may well replace red clover at times, in order to avoid clover sickness. (For results of field experiments on the brown silt loam prairie, see Tables 3 to 9.) Black Clay Loam (1120) Black clay loam represents the flat prairie and is sometimes called “gumbo” because of its sticky character. Its formation in flatter, poorly drained areas is due to the accumulation of organic matter and to the washing in of clay and fine silt from the slightly higher adjoining lands. This type occupies 168.69 square miles (17,961 acres) , or 14.47 percent of the entire area of the county. It is so flat that proper drainage is one of the most difficult problems in its management. The surface soil, 0 to 6% inches, is a black granular clay loam, varying lo- cally to a black clayey silt loam on the large flat areas. It contains, on an aver- age, 7.6 percent of organic matter, or 76 tons per acre, varying from 65 to 98 tons. In physical composition it varies somewhat as it grades into other types. As it passes toward the brown silt loam, which nearly always surrounds it, it be- comes more silty. Where it merges into the gravelly black clay loam (1120.2), it sometimes contains considerable quantities of sand and fine or medium gravel. The subsurface stratum has a thickness of 10 to 16 inches and varies from a black to a brownish gray clay loam, usually somewhat heavier than the surface soil. The average amount of organic matter is 4 percent, or 80 tons per acre. The lower part of this stratum frequently is a drab or yellowish drab silty clay. The stratum is quite pervious to water, owing to jointing or checking from shrinkage in times of drouth. The subsoil to a depth of 40 inches varies from a drab to a yellowish drab silty clay. As a rule, the iron is not highly oxidized, because of poor drainage and lack of aeration. Concretions of carbonate of lime are frequently found. The perviousness of the subsoil is about the same as the subsurface and is due to the same cause. When thrown out on the surface where wetting and drying may take place, it soon breaks into small cubical masses. Gravel is frequently present. Black clay loam presents many variations. Here, as elsewhere, the boun- dary lines between it and the brown silt loam are not always distinct. In some cases topography is a great help in locating the boundary, but in other cases there may be an intermediate zone of greater or less width. The washing in of silty 1915 ] McLean County 27 material from the surrounding higher lands, especially near the edges of the areas, modifies the character of the soil, giving the surface a silty character. This change is taking place more rapidly now, with the annual cultivation of the soil, than formerly, when washing was largely prevented by prairie grasses. Drainage is the first requirement in the management of this type ; altho it usually has but little slope, yet because of its perviousness it is easily tile-drained. Keeping the soil in good physical condition is very essential, and thoro drainage helps to do this to a great extent. As the organic matter is destroyed by cultiva- tion and nitrification, and as the limestone is removed by cropping and leaching, the physical condition of the soil becomes poorer, and as a consequence it becomes more difficult to work. Both organic matter and limestone tend to develop granu- lation. The former should be maintained by turning under manure or such crop residues as corn stalks and straw, and by the use of clover and pasture in rotations. Ground limestone should be applied when needed to keep the soil sweet. It should be remembered that the difficulty of working clay soils is in pro- portion to their deficiency in organic matter. While black clay loam is one of the best soils in the state, yet the clay and humus which it contains give it the property of shrinkage and expansion to such a degree as to be somewhat objectionable at times, especially during drouth. When the soil is wet, these constituents expand, and when the moisture evaporates or is. used by crops, they shrink. This results in the formation of cracks, sometimes as much as two or more inches in width and extending with lessening width to two or three feet in depth. During the drouth of 1914, the cracks were so large and deep that in many cases a one-inch auger. could be forced into them, without turn- ing, to a depth of more than two feet. These cracks allow the soil strata to dry out rapidly, and as a result the crop is injured thru lack of moisture. They may do considerable damage by “blocking out” hills of corn and severing the roots. While cracking may not be prevented entirely, good tilth with a soil mulch will do much toward that end. Both for aeration and for producing a mulch for conserving moisture, cultivation is more essential on this type than on the brown silt loam. It must be remembered, however, that cultivation should be as shallow as possible, in order to prevent injury to the roots of the corn. This type is fairly well supplied with plant food, which is usually liberated with sufficient rapidity by a good rotation and by the addition of moderate amounts of organic matter. The amount of organic matter added must be in- creased, of course, with continued farming, until the nitrogen supplied is equal to that removed. Altho the addition of phosphorus is not expected to produce marked profit, it is likely to pay its cost in the second or third rotation ; and even by main- taining the productive power of the land, the capital invested is protected. At Urbana, on the South Farm of the University of Illinois, a series of plots devoted chiefly to variety tests and other crop-production experiments ex- tends across an area of black clay loam. Where rock phosphate has been applied at the rate of 500 pounds an acre a year in connection with crop residues, in a four-year rotation of wheat, corn, oats, and clover (or soybeans), the value of the increase produced per ton of phosphate used in three successive rotation periods, has been $2.13, $4.70, and $6.48, respectively, at the “lower prices,” or $3.04, $6.71, and $9.26, respectively, at the “higher prices” for produce. In the live-stock system, the phosphorus naturally supplied in the manure, supple- 28 Soil Report No. 10 [May, merited by that liberated from this fertile soil, has thus far been nearly suffi- cient to meet the crop requirements ; the increase in crop values per ton of phos- phate applied having been, as an average for the twelve years, only $2.26 at the ‘ ‘ lower prices, ’ ’ or $3.26 at the ‘ ‘ higher prices. ’ ’ These returns are less than half the cost of the phosphorus applied, and some seasons no benefit appears. This type is rich in magnesium and calcium, and in the Wisconsin glacia- tion it usually contains plenty of carbonates. With continued cropping and leaching, applications of limestone will ultimately be needed. Gravelly Black Clay Loam (1120.2) Gravelly black clay loam occurs in the poorly drained areas in the eastern and northeastern part of the county in the large sloughs that, during parts of the year, were once covered with streams whose currents were sufficiently strong to carry and deposit considerable quantities of sand and small gravel. These materials have become mixed with the fine material and form a distinct phase of black clay loam. The surface soil, 0 to 6% inches, varies from 15 to 40 percent in the amount of gravel it contains, the gravel itself being mostly fine. The organic-matter content is not quite so high as in the black clay loam, being about 6.4 percent, or 64 tons per acre. The subsurface, extending from 6% to 18 or 20 inches, is a brown gravelly clay loam, containing about 3.2 percent of organic matter and passing at the lower limit into a less gravelly and much lighter colored clay loam. The subsoil varies from a drab to a pale yellowish drab, indicating poor oxidation. It does not usually contain as much gravel as either the surface or subsurface. Limestone concretions are frequently found. The management of this type is not different from that of the black clay loam, altho there may be a greater necessity for maintaining the supply of or- ganic matter because of the lower content of this constituent naturally in the soil. The presence of gravel affects the working of the soil only to a slight ex- tent, since clay possesses such distinctive properties that it takes a large amount of gravel and sand to overcome its effects. Hence this type works very little differently from the ordinary black clay loam. Brown-Gray Silt Loam on Tight Clay (1128) Brown-gray silt loam on tight clay occurs in numerous small areas thruout the county, principally in Township 23 North, Ranges 1 West and 1 East; also in the southwestern part of Township 24 North, Range 1 West. The total area occu- pied by this type is 2.42 square miles (1,549 acres), or .2 percent of the area of the county. While not of great importance from the standpoint of area, yet it is interesting to note that the tight clay soils, or so-called hardpan, have devel- oped under certain conditions even in the early Wisconsin glaciation. The top- ography is flat and naturally poorly drained. The surface soil, 0 to 6% inches, consists of a brown or grayish brown silt loam, containing some fine sand and coarse silt, which give it a peculiar, mealy feel but excellent texture. It contains about 4 percent of organic matter, or 40 tons per acre, and is somewhat richer in this constituent than the corresponding 1915 ] McLean County 29 type in southern Illinois. The organic-matter content varies with its relation to other types, being greater where it approaches brown silt loam (1126) and less where it passes into yellow-gray silt loam (1134). As a rule, the surface soil is not so granular as the ordinary brown silt loam. The subsurface is represented by a stratum 10 to 12 inches thick. The color varies from a brown to a gray or grayish brown, the upper part of the stratum usually being brown, while the lower part is decidedly gray or grayish brown. It differs from the surface soil principally in the amount of organic matter it contains, having 1.2 percent as compared with 4 percent in the top stratum. The natural subsoil begins at a depth of 16 to 18 inches, as a yellowish, almost impervious, silty clay, and has a thickness of 10 to 15 inches. It is usually underlain by a rather pervious silt. This tight clay layer obstructs drainage to such an extent that percolation is not very rapid, hence the soil dries very slowly. The land should be tiled thoroly, unless surface drainage is sufficient. In order to do this, the lines of tile should be placed not over four rods apart. Care should be taken, on this type, to maintain or increase the amount of or- ganic matter by the proper rotation of crops and the turning under of crop resi- dues and farm manures. Deep-rooting crops, such as red, mammoth, and sweet clover, should be grown so as to render the tight clay more permeable to air and water. From Table 2 it will be seen that the surface soil contains only 4,200 pounds of nitrogen and 1,380 pounds of phosphorus per acre. To increase these amounts, liberal applications of fine-ground rock phosphate should be made in connection with decaying organic matter, as on the brown silt loam. This type is distinctly acid in surface, subsurface, and subsoil. Limestone should be applied at the rate of 2 to 3 tons per acre every four to six years. The initial applications may well be 1 ton of phosphate and 4 tons of limestone. Gravelly Loam (1190 or 990) Gravelly loam occupies many areas on the upland but covers a total of only 96 acres. These areas are small and isolated, representing small gravel ridges re- cently covered by fine wind-blown material. The organic matter of the soil should be maintained, and in other respects the treatment should be the same as for the brown silt loam, except that phos- phorus need not be added, because of the deep feeding range afforded plant roots. (b) Upland Timber Soils The upland timber soils occur along streams, or, in some cases, on or near somewhat steep morainal ridges. They are characterized by a yellow, yellowish gray, or gray color, due to their low organic-matter content. This lack of or- ganic matter has been caused by the long-continued growth of forest trees. As the forests invaded the prairies, two effects were produced: (1) the shading of the trees prevented the growth of prairie grasses, the roots of which are mainly responsible for the large amount of organic matter in prairie soils; (2) the trees themselves added very little organic matter to the soil, for the leaves and branches either decayed completely or were burned by forest fires. As a result the or- ganic-matter content of the upland timber soils has been reduced until in some parts of the state a low condition of apparent equilibrium has been reached. 30 Soil Report No. 10 [May, Yellow-Gray Silt Loam (1134 or 934) Yellow-gray silt loam occurs in the outer timber belts along streams and in the less rolling of the timbered morainal areas. The type covers 73.42 square miles (46,989 acres), or 6.23 percent of the entire area of the county. In top- ography it is sufficiently rolling for good surface drainage, without much ten- dency to wash if proper care is taken. The surface soil, 0 to 6% inches, is a yellow, yellowish gray, gray, or brown- ish gray silt loam, incoherent but not granular. The more nearly level areas are gray in color, while the more rolling phase of the type has a yellow or brownish yellow color. As the type approaches the brown silt loam, it becomes decidedly darker. The organic-matter content averages 2.9 percent, or 29 tons per acre, but it varies considerably with topography. As the type approaches the brown silt loam, the organic matter amounts to as much as 3.8 percent, while as it ap- proaches the yellow silt loam, it diminishes to as low as 2.3 percent. In some cases it is extremely difficult to draw the line between the long-cultivated brown silt loam and the yellow-gray silt loam, because of the gradation between the types. The subsurface stratum varies from 3 to 10 inches in thickness, erosion hav- ing reduced its thickness on the more rolling areas. It is usually a gray, grayish yellow, or yellow silt loam, somewhat pulverulent, but becoming more coherent and plastic with depth. The amount of organic matter is about 1 percent, or 20 tons per acre in the four million pounds of soil. The subsoil is a yellow or mottled grayish yellow, clayey silt or silty clay, somewhat plastic when wet, but friable when only moist, and pervious to water. Glacial drift is sometimes encountered at a depth of less than 40 inches. This is due to the removal by erosion of part of the loessial material. The glacial drift may be locally a very gravelly deposit, but usually it is a slightly gravelly clay and in some places is lacking in permeability. Otherwise, each stratum of this type is quite pervious to water, except in the level gray areas, where the tight and more or less compact clayey layer has been formed at a depth of 18 to 24 inches. Small areas of light gray silt loam on tight clay are found in the county, but none large enough to be shown on the map. In the management of this type one of the most essential things is the main- taining or the increasing of organic matter. This is necessary in order to supply nitrogen and liberate mineral plant food, to give better tilth, to prevent ‘ ‘ running together, ’ ’ and on some of the more rolling phases, to prevent washing. Another essential is the neutralization of the acidity of the soil by the appli- cation of ground limestone, so that clover, alfalfa, and other legumes may be grown more successfully. The initial application may well be 4 or 5 tons per acre, after which 2 tons per acre every four or five years will be sufficient. Since the soil is poor in phosphorus, this element should be applied, preferably in con- nection with farm manure or clover plowed under. In permanent systems of farming, fine-ground natural rock phosphate will be found the most economical form in which to supply the phosphorus, altho steamed bone meal or acid phos- phate may well be used temporarily until plenty of decaying organic matter can be provided. For definite results from the most practical field experiments upon typical yellow-gray silt loam, we must go down into ‘ ‘ Egypt, ’ ’ where the people of Saline county, especially those in the vicinity of Raleigh and Galatia, have provided 1915 ] McLean County 31 the University with a very suitable tract of this type of soil for a permanent experiment field. There, as an average of duplicate trials each year for the four years 1911 to 1914, the crop values from four acres were $16.44 from untreated land, $18.22 where organic manures were applied in proportion to the amount of crops produced, and $33.58 where 6 tons per acre of limestone and the organic manures were applied, — the wheat, corn, oats, and clover (or cowpeas or soy- beans) grown in the rotation being valued at the “lower prices” heretofore men- tioned. Owing to the low supply of organic matter, phosphorus produced almost no benefit, as an average, during the first two years ; but with increasing applica- tions of organic matter, the effect of phosphorus is becoming more apparent in subsequent crops. Of course the full benefit of a four-year rotation cannot be realized during the first four years. The farm manure was applied to one field each year, and the fourth field received no manure until the fourth year. Like- wise, crop residues plowed under during the first rotation may not be fully recov- ered in subsequent increased yields until the second or third rotation period. While limestone is the material first needed for the economic improvement of the more acid soils of southern Illinois, with organic manures and phosphorus to follow in order, the less acid soils of the central part of the state are first in need of phosphorus, altho limestone and organic matter must also be provided for permanent and best results. Table 12 shows in detail thirteen years’ results secured from the Antioch soil experiment field located in Lake county on the yellow-gray silt loam of the late Wisconsin glaciation. In acidity this type in McLean county is intermediate between the similar soils in Saline and Lake counties, but no experiment field has been conducted on this important soil type in the early Wisconsin glaciation, in which McLean county is situated. The Antioch field was started in order to learn as quickly as possible what effect would be produced by the addition to this type of soil, of nitrogen, phos- phorus, and potassium, singly and in combination. These elements were all added in commercial form until 1911, after which the use of commercial nitrogen was discontinued and crop residues were substituted in its place. (See report of Urbana field for further explanations, page 7.) Only a small amount of lime was applied at the beginning, in harmony with the teaching which was common at that time; furthermore, Plot 101 proved to be abnormal, so that no conclu- sions can be drawn regarding the effect of lime. In order to ascertain the effect produced by additions of the different elements singly, Plot 102 must be re- garded as the check plot. Three other comparisons are also possible to deter- mine the effect of each element under different conditions. As an average of 40 tests (4 each year for ten years), liberal applications of commercial nitrogen produced a slight decrease in crop values; but as an average of thirteen years each dollar invested in phosphorus paid back $2.54 (Plot 104), while potassium applied in addition to phosphorus (Plot 108) pro- duced no increase, the crops being valued at the lower prices used in the tabular statement. Thus, while the detailed data show great variation, owing both to some irregularity of soil and to some very abnormal seasons, with three almost complete crop failures (1904, 1907, and 1910), yet the general summary strongly confirms the analytical data in showing the need of applying phosphorus and the profit from its use, and the loss in adding potassium. In most cases com- Soil Keport No. 10 ■** .. c3 ^ © 'Z* |s Bushels or tons per acre 30.8 30.0 40.8 54.2 34.0 41.3 43.2 46.0 41.0 37.8 Clover 1913’ O O IO CD C) 1.32 .72 C) C> 1.60 CC Oats 1912 21.3 17.5 24.4 49.1 18.8 46.9 16.9 35.9 31.9 38.1 Corn 1911 34.4 24.6 10.4 37.4 20.4 37.0 7.0 42.2 44.2 49.0 Corn 1910 CM O ^ OO CD rH CD' © CD CM CD rH CO* o o CO* TtH Wheat 1909 1 12.2 11.7 © CO iq CO go CO 00 © CM CO rH CD CO CM CM 30.5 34.5 Oats 1908 65.6 61.6 60.3 70.9 62.5 49.1 52.6 59.4 51.9 55.9 Corn 1907 12.4 9.5 6.4 13.4 12.9 20.9 11.1 18.3 31.4 28.8 Corn 1906 1 35.9 31.5 CO ^ 05 rji CO ID CO CO © H 05 05* 05* IO CO io 65.9 I 66.3 Wheat 1905 18.5 10.3 17.8 35.8 21.7 15.2 11.8 28.7 18.0 16.3 Oats 1904 17.8 1 12.8 loo iq o. ©d CM* 05 1 M 05 CO IO* © 05 31.9 37.2 Corn 1903 CD 05 c 6 oo CO CO 40.8 53.6 50.2 62.7 54.9 66.0 69.1 71.8 Corn 1902 TtH LO 46.3 50.1 48.2 OHS CD -‘ IO* tH © cm CM CM H CM | S © w O. bo ? a 5 §D &© [May, ’Crop residues in place of commercial nitrogen after 1911. ’Figures in parentheses indicate bushels of seed; the others, tons of hay. a No seed produced: clover plowed under on these plots. 1915] McLean County 33 Table 13. — Value of Crops per Acre in Thirteen Years, Antioch Field Plot Soil treatment applied Total value of thirteen crops Lower prices 1 Higher prices 2 101 None $135.12 $193.03 102 119.74 171.06 103 Lime, nitrogen 124.70 178.15 104 Lime, phosphorus 202.20 288.85 105 Lime, potassium 138.88 198.40 106 Lime, nitrogen, phosphorus T79.41 256.31 107 Lime, nitrogen, potassium 133.54 190.77 108 Nitrogen, phosphorus, potassium 201.35 287.65 109 Lime, nitrogen, phosphorus, potassium 191.22 273.18 110 Nitrogen, phosphorus, potassium 181.18 258.83 Value of Increase per Acre in Thirteen Years For nitrogen 1 $ 4.96 $ 7.09 For phosphorus 82.46 117.79 For nitrogen and phosphorus over phosphorus -22.79 -32.54 For phosphorus and nitrogen over nitrogen 54.71 78.16 For potassium, nitrogen, and phosphorus over nitrogen and phosphorus . . . 11.81 16.87 'Wheat at 70 cents a bushel, corn at 35 cents, oats at 28 cents, hay at $7 a ton. “Wheat at $1 a bushel, corn at 50 cents, oats at 40 cents, hay at $10 a ton. mercial nitrogen damaged the small grains by causing the crop to lodge ; but in those years when a corn yield of 40 bushels or more was secured by the appli- cation of phosphorus either alone or with potassium, then the addition of nitro- gen produced an increase. From a comparison of the results from the Urbana, Sibley, and Blooming- ton fields, we must conclude that better yields are to be secured by providing nitrogen by means of farm manure or legume crops grown in the rotation than by the use of commercial nitrogen, which is evidently too readily available, caus- ing too rapid growth and consequent weakness of straw ; and of course the at- mosphere is the most economic source of nitrogen where that element is needed for soil improvement in general farming. ( See Appendix for detailed discussion of “Permanent Soil Improvement.”) Yellow Silt Loam (1135 or 935) Yellow silt loam covers 27.43 square miles (17,555 acres) and constitutes 2.36 percent of the entire area of the county. It occurs as the hilly and badly eroded land on the inner timber belts adjacent to the streams, usually only in narrow, irregular strips with arms extending up the small valleys. In topog- raphy it is very rolling, and in most places so badly broken that it should not be cultivated because of the danger of injury from washing. The surface soil, 0 to 6% inches, is a yellow or grayish yellow, pulverulent silt loam. It varies greatly in color and texture, owing to recent washing. In places the natural subsoil may be exposed. This exposure gives it a decidedly yellow color. The soil freshly plowed appears yellow or brownish yellow, but when it becomes dry after a rain, it is of a grayish color. In some places the surface soil is formed from glacial drift, but this is only on very limited areas and on the steepest slopes. The organic-matter content is the lowest of any type in the county, being only 1.5 percent, or 15 tons per acre. It varies, however, from 1.2 to 1.8 percent. 34 Soil Repoet No. 10 [May, The subsurface varies from a yellow silt loam to a yellow clayey silt loam, and on the steepest slopes may consist of weathered glacial drift. The thickness of the stratum varies from 5 to 12 inches, depending on the amount of recent erosion. The organic-matter content amounts to only 12 tons per acre. The subsoil consists normally of a yellow clayey silt, but in some areas may be composed entirely of glacial drift. The first and most important thing in the management of this type is to pre- vent general surface washing and gullying. If the land is cropped at all, a rota- tion should be practiced that will require a cultivated crop as little as possible, and allow pasture and meadow most of the time. If tilled, the land should be plowed deeply and contours should be followed as nearly as possible in plowing, planting, and cultivating. Furrows should not be made up and down the slopes. Every means should be employed to maintain and increase the organic-matter content. This will help hold the soil and keep it in good physical condition so that it will absorb a large amount of water and thus diminish the run-off. (See Circular 119, “Washing of Soils and Methods of Prevention.”) Additional treatment recommended for this yellow silt loam is the liberal use of limestone wherever cropping is practiced. This type is quite acid and very deficient in nitrogen; and the limestone, by correcting the acidity of the soil, is especially beneficial to the clover grown to increase the supply of nitro- gen. Where this soil has been long cultivated and thus exposed to surface wash- ing, it is particularly deficient in nitrogen ; indeed, on such lands the low supply of nitrogen is the factor that first limits the growth of grain crops. This fact is very strikingly illustrated by the results from two pot-culture experiments re- ported in Tables 14 and 15, and shown photographically in Plates 7 and 8. In one experiment, a large quantity of the typical worn hill soil was col- lected from two different places. 1 Each lot of soil was thoroly mixed and put in ten four- gallon jars. Ground limestone was added to all the jars except the first and last in each set, those two being retained as control or check pots. The elements nitrogen, phosphorus, and potassium were added singly and in com- bination, as shown in Table 14. As an average, the nitrogen applied produced a yield about eight times as large as that secured without the addition of nitrogen. While some variations in yield are to be expected, because of differences in the individuality of seed or other uncontrolled causes, yet there is no doubting the plain lesson taught by these actual trials with growing plants. The question arises next, Where is the farmer to secure this much-needed nitrogen ? To purchase it in commercial fertilizers would cost too much ; indeed, under average conditions the cost of the nitrogen in such fertilizers is greater than the value of the increase in crop yields. But there is no need whatever to purchase nitrogen, for the air contains an inexhaustible supply of it, which, under suitable conditions, the farmer can draw upon, not only without cost, but with profit in the getting. Clover, alfalfa, cow- peas, and soybeans are not only worth raising for their own sake, but they have the power to secure nitrogen from the atmosphere if the soil contains limestone- and the proper nitrogen-fixing bacteria. 1 Soil for wheat pots from loess-covered unglaciated area, and that for oat pots from/ upper Illinois glaciation. 1915] McLean County * 35 To secure further information along this line, another experiment with pot cultures was conducted for several years with the same type of worn hill soil as that used for wheat in the former experiment. The results are reported in Table 15. To three pots (Nos. 3, 6, and 9) nitrogen was applied in commercial form, at an expense amounting to more than the total value of the crops produced. In three other pots (Nos. 2, 11, and 12) a crop of cowpeas was grown during the late summer and fall and turned under before the wheat or oats were planted. Pots 1 and 8 served for important comparisons. After the second cover crop of cowpeas had been turned under, the yield from Pot 2 exceeded that from Pot 3 ; and in the subsequent years the legume green manures produced, as an average, rather better results than the commercial nitrogen. This experiment confirms that reported in Table 14, in showing the very great need of nitrogen for the improvement of this type of soil, and it also shows that nitrogen need not be purchased but that it can be obtained from the air by growing legume crops and plowing them under as green manure. Of course the soil can be very markedly improved by feeding the legume crops to live stock and returning the resulting Plate 7. — Wheat in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (See Table 14) Table 14. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land (Grams per pot) Pot No. Soil treatment applied Wheat Oats 1 None 3 5 2 Limestone 4 4 3~ Limestone, nitrogen 26 45 4 Limestone, phosphorus 3 6 5 Limestone, potassium 3 5 6 Limestone, nitrogen, phosphorus 34 38 7 Limestone, nitrogen, potassium 33 46 8 Limestone, phosphorus, potassium 2 5 9 Limestone, nitrogen, phosphorus, potassium 34 38 10 3 5 Average yield with nitrogen 32 42 Average yield without nitrogen 3 5 Average train for nitrocron 29 37 36 Soil Report No. 10 [May, farm manure to the land, if legumes are grown frequently enough and if the farm manure produced is sufficiently abundant and is saved and applied with care. As a rule, it is not advisable to try to enrich this type of soil in phosphorus, for with the erosion that is sure to occur to some extent the phosphorus supply will be renewed from the subsoil. Probably the best legumes for this type of soil are sweet clover and alfalfa. On soil deficient in organic matter sweet clover grows better than almost any other legume, and the fact that it is a very deep-rooting plant makes it of value in increasing organic matter and preventing washing. Worthless slopes that have been ruined by washing may be made profitable as pasture by growing sweet clover. The blue grass of pastures may well be supplemented by sweet clover and alfalfa, and a larger growth obtained, because the legumes provide the neces- sary nitrogen for the blue grass. To get alfalfa well started requires the liberal use of limestone, thoro inocu- lation with nitrogen-fixing bacteria, and a moderate application of farm manure. If manure is not available, it is well to apply abodt 500 pounds per acre of acid phosphate, or steamed bone meal, mix it with the soil, by disking if possible, and then plow it under. The limestone (about 5 tons) should be applied after plow- ing and should be mixed with the surface soil in the preparation of the seed bed. The special purpose of this treatment is to give the alfalfa a quick start in order that it may grow rapidly and thus protect the soil from washing. Plate 8. — Wheat in Pot-Culture Experiment with Yellow Silt Loam op Worn Hill Land (See Table 15) Table 15. — Crop Yields in Pot-Culture Experiment with Yellow Silt Loam of Worn Hill Land and Nitrogen-Fixing Green Manure Crops (Grains per pot) Pot No. Soil treatment 1903 Wheat 1904 Wheat 1905 Wheat 1906 | Wheat 1907 Oats 1 None 5 4 4 4 6 2 Limestone, legume 10 17 26 19 37 11 Limestone, legume, phosphorus 14 19 20 18 27 12 Limestone, legume, phosphorus, potassium. . 16 20 21 19 30 3 Limestone, nitrogen 17 14 15 9 28 6 Limestone, nitrogen, phosphorus 26 20 18 18 30 9 Limestone, nitrogen, phosphorus, potassium 31 34 21 20 26 8 Limestone, phosphorus, potassium 3 3 5 3 7 1915 ] McLean County 37 (c) Terrace Soils Terrace soils were formed on terraces or old fills in valleys. The terraces owe their formation generally to the deposition of material from an overloaded and flooded stream during the melting of the glaciers. The material varied from fine to coarse. These valleys were sometimes filled almost to the height of the upland. Later the streams cut down thru these fills and developed new bottom lands, or flood plains, at a lower level, leaving part of the old fill as a terrace. The lowest and most recently formed bottom land is called first bottom. The higher land no longer flooded (or very rarely, at most) is generally designated as second bottom. Finer material later deposited on this sand and gravel of the fill now constitutes the soil. The terraces occur along the Mackinaw and Sangamon rivers. Brown Silt Loam over Gravel (1527) Brown silt loam over gravel occurs along the Sangamon river in very limi- ted areas. The total area is only 166 acres. The surface soil, 0 to 6% inches, is a brown to a dark brown silt loam, con- taining some sand and 5.7 percent of organic matter, or 57 tons per acre. The topography is slightly undulating. The subsurface soil varies from a brown to a yellowish brown or yellowish drab silt loam, and the lower part of the stratum at a depth of 16 to 18 inches contains fragments of sand and gravel. The subsoil is a yellowish or drab-colored silt or clayey silt, which becomes quite gravelly at 35 to 48 inches and passes into rather a pure gravel. This type, as a rule, is well drained, because of the pervious character of the subsoil. The treatment should be the same as for brown silt loam, except that the addition of phosphorus is not likely to be profitable, because of the deep feeding range afforded plant roots. < Brown Silt Loam on Gravel (1526.2) Brown silt loam on gravel covers an area of 1.77 square miles (1,132 acres) , or only .15 percent of the total area of the county. It differs from the brown silt loam over gravel only in the fact that gravel is within 30 inches of the surface. Because of the nearness of the gravel the type is more susceptible to drouth than if this stratum were deeper. The treatment for this type should be practically the same as for the preced- ing. There is, however, a greater necessity for increasing the organic matter, because the soil contains less of that constituent. Yellow-Gray Silt Loam on Gravel (1534.2) Yellow-gray silt loam on gravel is found along both the Mackinaw and San- gamon rivers. It represents the terrace soil that has been covered by a growth of trees and is consequently low in organic matter. The total area is 621 acres. The surface soil, 0 to 6% inches, is a yellow or yellowish gray silt loam with an organic-matter content of 3.1 percent, or 31 tons per acre. The subsurface is a yellow silt loam containing a perceptible amount of sand. The subsoil is a yellow silt or clayey silt, passing into the gravel at a depth of 12 to 30 inches. Local borings are obtained where the gravel layer may be slightly below 30 inches. 38 Soil Report No. 10 [May, This soil needs nitrogen and organic matter as the most essential things in its improvement. (d) Swamp and Bottom-Land Soils Deep Peat (1401) A few small areas of deep peat, aggregating 83 acres, are mapped in this county. They occur in low, poorly drained places in bottom land or swamps. The surface soil, 0 to 6% inches, is black, generally well decomposed, and contains about 55 percent of organic matter. The subsurface is very similar to the surface, but the organic-matter content is not so high, being about 50 percent. The subsoil is quite variable ; in some places it passes into a drab silty clay and in others it is peaty to a depth of 40 inches. It frequently contains shells mingling with the organic matter. Drainage is of course the first essential for this type. If it does not produce well when drained, trials should be made with potassium. (See Bulletin 157.) Deep Brown Silt Loam ( Bottom Land) (1426) Deep brown silt loam occurs along the streams, chiefly in the southwestern part of the county. It aggregates 23.88 square miles, or 2 percent of the county. The surface soil, 0 to 6% inches, is a brown silt loam containing from 5 to 8 percent of organic matter. It varies somewhat in physical composition from a heavy phase to one containing sand in sufficient amounts to be called a sandy loam. This latter, however, does not occur in areas large enough to be mapped. The subsurface soil is similar to the surface except that the organic-matter content is slightly lower, varying from 4 to 7 percent, and consequently the soil is a little lighter in color. The subsoil is not so dark as the surface and contains local areas of coarse material. Where proper drainage is secured, this type is very productive. As a rule, where it is subject to frequent overflow nothing else is needed except good farm- ing. Even the systematic rotation of crops is not so important where the land is subject to occasional overflow; but where it lies high or is protected from over- flow by dikes, a rotation including legume crops should be practiced, and ulti- mately provision should be made for the enrichment of such protected land in both phosphorus and organic matter, and, if acid, in limestone. Mixed Loam ( Bottom Land) (1454) Mixed loam occurs chiefly north of the Bloomington moraine. It aggregates 18 square miles, or 1.5 percent of the county. It varies quite widely in its physi- cal composition, including sand, sandy loam, silt loam, and possibly some clay loam. Its character changes more or less with each flood ; hence it is impracti- cable to attempt to separate it into distinct types. The amount of organic matter in the surface soil is about 5.5 percent, which is equivalent to 55 tons per acre. The subsurface is a dark soil, varying in physical composition from a sandy loam to a clay loam. The organic-matter content is about 4.6 percent. The subsoil is slightly lighter in color than the subsurface, with a variable composition similar to that of the other strata. This type is fertile, and no treatment is suggested beyond that mentioned for the preceding type, deep brown silt loam. 1915] McLean County 39 APPENDIX A study of the soil map and the tabular statements concerning crop require- ments, the plant-food content of the different soil types, and the actual results secured from definite field trials with different methods or systems of soil im- provement, and a careful study of the discussion of general principles and of the descriptions of individual soil types, will furnish the most necessary and use- ful information for the practical improvement and permanent preservation of the productive power of every kind of soil on every farm in the county. More complete information concerning the most extensive and important soil types in the great soil areas in all parts of Illinois is contained in Bulletin 123, “The Fertility in Illinois Soils,” which contains a colored general soil-survey map of the entire state. Other publications of general interest are : Bulletin No. 76, “Alfalfa on Illinois Soils” Bulletin No. 94, ‘ ‘ Nitrogen Bacteria and Legumes ’ ’ Bulletin No. 115, “Soil Improvement for the Worn Hill Lands of Illinois” Bulletin No. 125, “Thirty Years of Crop Botation on the Common Prairie Lands of Illinois” Circular No. 82, ‘ ‘ Physical Improvement of Soils ’ ’ Circular No. 110, “Ground Limestone for Acid Soils” Circular No. 127, “Shall We Use Natural Rock Phosphate or Manufactured Acid Phos- phate for the Permanent Improvement of Illinois Soils?” Circular No. 129, “The Use of Commercial Fertilizers” Circular No. 149, “Results of Scientific Soil Treatment” and “Methods and Results of Ten Years’ Soil Investigation in Illinois” Circular No. 165, “Shall We Use ‘Complete’ Commercial Fertilizers in the Corn Belt?” Circular No. 167, “The Illinois System of Permanent Fertility” Note. — Information as to where to obtain limestone, phosphate, bone meal, and potas- sium salts, methods of application, etc., will also be found in Circulars 110 and 165. Soil Survey Methods The detail soil survey of a county consists essentially of ascertaining, and indicating on a map, the location and extent of the different soil types; and, since the value of the survey depends upon its accuracy, every reasonable means is employed to make it trustworthy. To accomplish this object three things are essential : first, careful, well-trained men to do the work ; second, an accurate base map upon which to show the results of the work; and, third, the means necessary to enable the men to place the soil-type boundaries, streams, etc., accurately upon the map. The men selected for the work must be able to keep their location exactly and to recognize the different soil types, with their principal variations and lim- its, and they must show these upon the maps correctly. A definite system is employed in checking up this work. As an illustration, one soil expert will sur- vey and map a strip 80 rods or 160 rods wide and any convenient length, while his associate will work independently on another strip adjoining this area, and, if the work is correctly done, the soil type boundaries must match up on the line between the two strips. An accurate base map for field use is absolutely necessary for soil mapping. The base maps are made on a scale of one inch to the mile. The official data of the original or subsequent land survey are used as a basis in the construc- tion of these maps, while the most trustworthy county map available is used in 40 Soil Report No. 10 [May, locating temporarily the streams, roads, and railroads. Since the best of these published maps have some inaccuracies, the location of every road, stream, and railroad must be verified by the soil surveyors, and corrected if wrongly located. In order to make these verifications and corrections, each survey party is pro- vided with an odometer for measuring distances, and a plane table for deter- mining directions of angling roads, railroads, etc. Each surveyor is provided with a base map of the proper scale, which is carried with him in the field ; and the soil-type boundaries, ditches, streams, and necessary corrections are placed in their proper locations upon the map while the mapper is on the area. Each section, or square mile, is divided into 40-acre plots on the map, and the surveyor must inspect every ten acres and determine the type or types of soil composing it. The different types are indicated on the map by different colors, pencils for this purpose being carried in the field. A small auger 40 inches long forms for each man an invaluable tool with which he can quickly secure samples of the different strata for inspection. An extension for making the auger 80 inches long is carried by each party, so that any peculiarity of the deeper subsoil layers may be studied. Each man carries a compass to aid in keeping directions. Distances along roads are measured by an odometer attached to the axle of the vehicle, while distances in the field off the roads are determined by pacing, an art in which the men become expert by practice. The soil boundaries can thus be located with as high a degree of ac- curacy as can be indicated by pencil on the scale of one inch to the mile. The unit in the soil survey is the soil type, and each type possesses more or less definite characteristics. The line of separation between adjoining types is usually distinct, but sometimes one type grades into another so gradually that it is very difficult to draw the line between them. In such exceptional cases, some slight variation in the location of soil-type boundaries is unavoidable. Several factors must be taken into account in establishing soil types. These are (1) the geological origin of the soil, whether residual, glacial, loessial, al- luvial, colluvial, or cumulose; (2) the topography, or lay of the land; (3) the native vegetation, as forest or prairie grasses; (4) the structure, or the depth and character of the surface, subsurface, and subsoil; (5) the physical, or me- chanical, composition of the different strata composing the soil, as the percent- ages of gravel, sand, silt, clay, and organic matter which they contain; (6) the texture, or porosity, granulation, friability, plasticity, etc.; (7) the color of the strata; (8) the natural drainage; (9) the agricultural value, based upon its natural productiveness; (10) the ultimate chemical co ^position and reaction. The common soil constituents are indicated in the following outline : Soil Characteristics Organic matter I Comprising undeeomposed and partially decayed vegetable or organic material Soil constituents Inorganic matter [Clay. Silt. 001 mm. to .03 mm. . .03 mm. to 1. mm. . . . 1. mm. to 32 mm. . . .32. mm. and over ,001 mm. 1 and less Further discussion of these constituents is given in Circular 82. *25 millimeters equal 1 inch. 1915] McLean County 41 Groups op Soil Types The following gives the different general groups of soils: Peats — Consisting of 35 percent or more of organic matter, sometimes mixed with more or less sand or silt. Peaty loams — 15 to 35 percent of organic matter mixed with much sand. Some silt and a little clay may be present. Mucks — 15 to 35 percent of partly decomposed organic matter mixed with much clay and silt. Clays — Soils with more than 25 percent of clay, usually mixed with much silt. Clay loams — Soils with from 15 to 25 percent of clay, usually mixed with much silt and some sand. Silt loams — Soils with more than 50 percent of silt and less than 15 percent of clay, mixed with some sand. Loams — Soils with from 30 to 50 percent of sand mixed with much silt and a little clay. Sandy loams — Soils with from 50 to 75 percent of sand. Fine sandy loams — Soils with from 50 to 75 percent of fine sand mixed with much silt and little clay. Sands — Soils with more than 75 percent of sand. Gravelly loams — Soils with 25 to 50 percent of gravel with much sand and some silt. Gravels — Soils with more than 50 percent of gravel and much sand. Stony loams — Soils containing a considerable number of stones over one inch in diameter. Kock outcrop — Usually ledges of rock having no direct agricultural value. More or less organic matter is found in all the above groups. Supply and Liberation op Plant Food The productive capacity of land in humid sections depends almost wholly upon the power of the soil to feed the crop ; and this, in turn, depends both upon the stock of plant food contained in the soil and upon the rate at which it is liberated, or rendered soluble and available for use in plant growth. Protection from weeds, insects, and fungous diseases, tho exceedingly important, is not a positive but a negative factor in crop production. The chemical analysis of the soil gives the invoice of fertility actually pres- ent in the soil strata sampled and analyzed, but the rate of liberation is gov- erned by many factors, some of which may be controlled by the farmer, while others are largely beyond his control. Chief among the important controllable factors which influence the liberation of plant food are limestone and decaying organic matter, which may be added to the soil by direct application of ground limestone and farm manure. Organic matter may be supplied also by green- manure crops and crop residues, such as clover, cowpeas, straw, and corn stalks. The rate of decay of organic matter depends largely upon its age and origin, and it may be hastened by tillage. The chemical analysis shows correctly the 42 Soil Report No. 10 \May, total organic carbon, which represents, as a rule, but little more than half the organic matter ; so that 20,000 pounds of organic carbon in the plowed soil of an acre correspond to nearly 20 tons of organic matter. But this organic mat- ter consists largely of the old organic residues that have accumulated during the past centuries because they were resistant to decay, and 2 tons of clover or cuwpeas plowed under may have greater power to liberate plant food than the 20 tons of old, inactive organic matter. The recent history of the individual farm or field must be depended upon for information concerning recent addi- tions of active organic matter, whether in applications of farm manure, in legume crops, or in grass-root sods of old pastures. Probably no agricultural fact is more generally known by farmers and land- owners than that soils differ in productive power. Even tho plowed alike and at the same time, prepared the same way, planted the same day with the same kind of seed, and cultivated alike, watered by the same rains and warmed by the same sun, nevertheless the best acre may produce twice as large a crop as the poorest acre on the same farm, if not, indeed, in the same field ; and the fact should be repeated and emphasized that with the normal rainfall of Illi- nois the productive power of the land depends primarily upon the stock of plant food contained in the soil and upon the rate at which it is liberated, just as the success of the merchant depends primarily upon his stock of goods and the rapidity of sales. In both cases the stock of any commodity must be increased or renewed whenever the supply of such commodity becomes so depleted as to limit the success of the business, whether on the farm or in the store. As the organic matter decays, certain decomposition products are formed, including much carbonic acid, some nitric acid, and various organic acids, and these have power to act upon the soil and dissolve the essential mineral plant foods, thus furnishing soluble phosphates, nitrates, and other salts of potassium, magnesium, calcium, etc., for the use of the growing crop. As already explained, fresh organic matter decomposes much more rapidly than old humus, which represents the organic residues most resistant to decay and which consequently has accumulated in the soil during the past centuries. The decay of this old humus can be hastened both by tillage, which maintains a porous condition and thus permits the oxygen of the air to enter the soil more freely and to effect the more rapid oxidation of the organic matter, and also by incorporating with the old, resistant residues some fresh organic matter, such as farm manure, clover roots, etc., which decay rapidly and thus furnish or lib- erate organic matter and inorganic food for bacteria, the bacteria, under such favorable conditions, appearing to have power to attack and decompose the old humus. It is probably for this reason that peat, a very inactive and inefficient fertilizer when used by itself, becomes much more effective when composted with fresh farm manure ; so that two tons of the compost 1 may be worth as much as two tons of manure, but if applied separately, the peat has little value. Bac- terial action is also promoted by the presence of limestone. The condition of the organic matter of the soil is indicated more or less definitely by the ratio of carbon to nitrogen. As an average, the fresh organic 1 In his book, “Fertilizers,” published in 1839, Cuthbert W. Johnson reported such com- post to have been much used in England and to be valued as highly, ‘ ‘ weight for weight, as farm-yard dung.” 1915] McLean County 43 matter incorporated with soils contains about twenty times as much carbon as nitrogen, but the carbohydrates ferment and decompose much more rapidly than the nitrogenous matter ; and the old resistant organic residues, such as are found in normal subsoils, commonly contain only five or six times as much carbon as nitrogen. Soils of normal physical composition, such as loam, clay loam, silt loam, and fine sandy loam, when in good productive condition, contain about twelve to fourteen times as much carbon as nitrogen in the surface soil ; while in old, worn soils that are greatly in need of fresh, active, organic manures, the ratio is narrower, sometimes falling below ten of carbon to one of nitrogen. Soils of cut-over or burnt-over timber lands sometimes contain so much partially decayed wood or charcoal as to destroy the value of the nitrogen-carbon ratio for the purpose indicated. (Except in newly made alluvial soils, the ratio is usually narrower in the subsurface and subsoil than in the surface stratum.) It should be kept in mind that crops are not made out of nothing. They are composed of ten different elements of plant food, every one of which is absolutely essential for the growth and formation of every agricultural plant. Of these ten elements of plant food, only two (carbon and oxygen) are secured from the air by all agricultural plants, only one (hydrogen) from water, and seven from the soil. Nitrogen, one of these seven elements secured from the soil by all plants, may also be secured from the air by one class of plants (legumes), in case the amount liberated from the soil is insufficient; but even these plants (which include only the clovers, peas, beans, and vetches, among our common agricultural plants) secure from the soil alone six elements (phos- phorus, potassium, magnesium, calcium, iron, and sulfur), and also utilize the soil nitrogen so far as it becomes soluble and available during their period of growth. Plants are made of plant-food elements in just the same sense that a build- ing is made of wood and iron, brick, stone, and mortar. Without materials, nothing material can be made. The normal temperature, sunshine, rainfall, and length of season in central Illinois are sufficient to produce 50 bushels of wheat per acre, 100 bushels of corn, 100 bushels of oats, and 4 tons of clover hay ; and, where the land is properly drained and properly tilled, such crops would fre- quently be secured if the plant foods were present in sufficient amounts and liberated at a sufficiently rapid rate to meet the absolute needs of the crops. Crop Requirements The accompanying table shows the requirements of wheat, corn, oats, and clover for the five most important plant-food elements which the soil must fur- nish. (Iron and sulfur are supplied normally in sufficient abundance compared with the amounts needed by plants, so that they are never known to limit the yield of general farm crops grown under normal conditions.) To be sure, these are large yields, but shall we try to make possible the production of yields only half or a quarter as large as these, or shall we set as our ideal this higher mark, and then approach it as nearly as possible with profit? Among the four crops, corn is the largest, with a total yield of more than six tons per acre; and yet the 100-bushel crop of corn is often produced on rich pieces of land in good seasons. In very practical and profitable systems 44 Soil Report No. 10 [May, Table A. — Plant Pood in Wheat, Corn, Oats, and Clover Produce Nitro- Phos- Potas- Magne- Cal- Kind Amount gen phorus sium sium cium lbs. lbs. lbs. lbs. lbs. Wheat, grain 50 bu. 71 12 13 4 1 Wheat straw 2% tons 25 4 45 4 10 Corn, grain 100 bu. 100 17 19 7 1 Corn stover 3 tons 48 6 52 10 21 Corn cobs % ton 2 2 Oats, grain 100 bu. 66 11 16 4 2 Oat straw 2% tons 31 5 52 7 15 Clover seed 4bu. 7 2 3 1 1 Clover hay 4 tons 160 20 120 31 117 Total in grain and seed 244 1 42 51 16 4 Total in four crops. . 510 1 77 322 68 168 3 These amounts include the nitrogen contained in the clover seed or hay, which, how- ever, may be secured from the air. of farming, the Illinois Experiment Station has produced, as an average of the six years 1905 to 1910, a yield of 87 bushels of corn per acre in grain farming (with limestone and phosphorus applied, and with crop residues and legume crops turned under), and 90 bushels per acre in live-stock farming (with lime- stone, phosphorus, and manure) . The importance of maintaining a rich surface soil cannot be too strongly emphasized. This is well illustrated by data from the Rothamsted Experiment Station, the oldest in the world. On Broadbalk field, where wheat has been grown since 1844, the average yields for the ten years 1892 to 1901 were 12.3 bushels per acre on Plot 3 (unfertilized) and 31.8 bushels on Plot 7 (well ferti- lized), but the amounts of both nitrogen and phosphorus in the subsoil (9 to 27 inches) were distinctly greater in Plot 3 than in Plot 7, thus showing that the higher yields from Plot 7 were due to the fact that the plowed soil had been enriched. In 1893 Plot 7 contained per acre in the surface soil (0 to 9 inches) about 600 pounds more nitrogen and 900 pounds more phosphorus than Plot 3. Even a rich subsoil has little value if it lies beneath a worn-out surface. Methods of Liberating Plant Food Limestone and decaying organic matter are the principal materials which the farmer can utilize most profitably to bring about the liberation of plant food. The limestone corrects the acidity of the soil and thus encourages the development not only of the nitrogen-gathering bacteria which live in the nodules on the roots of clover, cowpeas, and other legumes, but also the nitrifying bacteria, which have power to transform the insoluble and unavailable organic nitrogen into soluble and available nitrate nitrogen. At the same time, the products of this decomposition have power to dissolve the minerals contained in the soil, such as potassium and magnesium, and also to dissolve the insoluble phosphate and limestone which may be applied in low-priced forms. Tillage, or cultivation, also hastens the liberation of plant food by permit- ting the air to enter the soil and burn out the organic matter; but it should never be forgotten that tillage is wholly destructive, that it adds nothing what- .1915 J McLean County 45 ever to the soil, but always leaves it poorer. Tillage should be practiced so far as is necessary to prepare a suitable seed bed for root development and also for the purpose of killing weeds, but more than this is unnecessary and unprofitable in seasons of normal rainfall ; and it is much better actually to enrich the soil by proper applications or additions, including limestone and organic matter (both of which have power to improve the physical condition as well as to liberate plant food) than merely to hasten soil depletion by means of excessive cultivation. Permanent Soil Improvement The best and most profitable methods for the permanent improvement of the common soils of Illinois are as follows: (1) If the soil is acid, apply at least two tons per acre of ground lime- stone, preferably at times magnesian limestone (CaC0 3 MgC0 3 ) , which con- tains both calcium and magnesium and has slightly greater power to correct soil acidity, ton for ton, than the ordinary calcium limestone (CaC0 3 ) ; and continue to apply about two tons per acre of ground limestone every four or five years. On strongly acid soils, or on land being prepared for alfalfa, five tons per acre of ground limestone may well be used for the first application. (2) Adopt a good rotation of crops, including a liberal use of legumes, and increase the organic matter of the soil either by plowing under the legume crops and other crop residues (straw and corn stalks), or by using for feed and bed- ding practically all the crops raised and returning the manure to the land with the least possible loss. No one can say in advance what will prove to be the best rotation of crops, because of variation in farms and farmers, and in prices for produce, but the following are suggested to serve as models or outlines: First year, corn. Second year, corn. Third year, wheat or oats (with clover or clover and grass). Fourth year, clover or clover and grass. Fifth year, wheat and clover or grass and clover. Sixth year, clover or clover and grass. Of course there should be as many fields as there are years in the rotation. In grain farming, with small grain grown the third and fifth years, most of the coarse products should be returned to the soil, and the clover may be clipped and left on the land (only the clover seed being sold the fourth and sixth years) ; or, in live-stock farming, the field may be used three years for timothy and clover pasture and meadow if desired. The system may be reduced to a five- year rotation by cutting out either the second or the sixth year, and to a four- year system by omitting the fifth and sixth years. With two years of corn, followed by oats with clover-seeding the third year, and by clover the fourth year, all produce can be used for feed and bedding if other land is available for permanent pasture. Alfalfa may be grown on a fifth field for four or eight years, which is to be alternated with one of the four ; or the alfalfa may be moved every five years, and thus rotated over all five fields every twenty-five years. Other four-year rotations more suitable for grain farming are : Wheat (and clover), corn, oats, and clover; or corn (and clover), cowpeas, wheat, and clover. (Alfalfa may be grown on a fifth field and rotated every five years, the hay being sold.) Soil Report No. 10 [May, 46 Good th ree-year rotations are: Corn, oats, and clover; corn, wheat, and clover; or wheat (and clover), corn (and clover), and cowpeas, in which two cover crops and one regular crop of legumes are grown in three years. A five-year rotation of (1) corn (and clover), (2) cowpeas, (3) wheat, (4) clover, and (5) wheat (and clover) allows legumes to be seeded four times. Alfalfa may be grown on a sixth field for five or six years in the combination, rotation, alternating between two fields every five years, or rotating over all the fields if moved every six years. To avoid clover sickness it may sometimes be necessary to substitute sweet clover or alsike for red clover in about every third rotation, and at the same time to discontinue its use in the cover-crop mixture. If the corn crop is not too rank, cowpeas or soybeans may also be used as a cover crop (seeded at the last cultivation) in the southern part of the state, and, if necessary to avoid disease, these may well alternate in successive rotations. For easy figuring it may well be kept in mind that the following amounts of nitrogen are required for the produce named: 1 bushel of oats (grain and straw) requires 1 pound of nitrogen. 1 bushel of corn (grain and stalks) requires 1% pounds of nitrogen. 1 bushel of wheat (grain and straw) requires 2 pounds of nitrogen. 1 ton of timothy requires 24 pounds of nitrogen. 1 ton of clover contains 40 pounds of nitrogen. 1 ton of cowpeas contains 43 pounds of nitrogen. 1 ton of average manure contains 10 pounds of nitrogen. The roots of clover contain about half as much nitrogen as the tops, and the roots of cowpeas contain about one-tenth as much as the tops. Soils of moderate productive power will furnish as much nitrogen to clover (and two or three times as much to cowpeas) as will be left in the roots and stubble. In grain crops, such as wheat, corn, and oats, about two-thirds of the nitrogen is contained in the grain and one-third in the straw or stalks. (See also discussion of “The Potassium Problem,” on pages following.) (3) On all lands deficient in phosphorus (except on those susceptible to serious erosion by surface washing or gullying) apply that element in consid- erably larger amounts than are required to meet the actual needs of the crops desired to be produced. The abundant information thus far secured shows posi- tively that fine-ground natural rock phosphate can be used successfully and very profitably, and clearly indicates that this material will be the most economical form of phosphorus to use in all ordinary systems of permanent, profitable soil improvement. The first application may well be one ton per acre, and subse- quently about one-half ton per acre every four or five years should be applied, at least until the phosphorus content of the plowed soil reaches 2,000 pounds per acre, which may require a total application of from three to five or six tons per acre of raw phosphate containing 121/2 percent of the element phosphorus. Steamed bone meal and even acid phosphate may be used in emergencies, but it should always be kept in mind that phosphorus delivered in Illinois costs about 3 cents a pound in raw phosphate (direct from the mine in carload lots), but 10 cents a pound in steamed bone meal, and about 12 cents a pound in acid phosphate, both of which cost too much per ton to permit their common purchase by farmers in carload lots, which is not the case with limestone or raw phos- phate- 1915 ] McLean County 47 Phosphorus once applied to the soil remains in it until removed in crops, unless carried away mechanically by soil erosion. (The loss by leaching is only about li /2 pounds per acre per annum, so that more than 150 years would be required to leach away the phosphorus applied in one ton of raw phosphate.) The phosphate and limestone may be applied at any time during the rota- tion, but a good method is to apply the limestone after plowing and work it into the surface soil in preparing the seed bed for wheat, oats, rye, or barley, where clover is to be seeded ; while phosphate is best plowed under with farm manure, clover, or other green manures, which serve to liberate the phosphorus. (4) Until the supply of decaying organic matter has been made adequate, on the poorer types of upland timber and gray prairie soils some temporary benefit may be derived from the use of a soluble salt or a mixture of salts, such as kainit, which contains both potassium and magnesium in soluble form and also some common salt (sodium chlorid). About 600 pounds per acre of kainit applied and turned under with the raw phosphate will help to dissolve the phos- phorus as well as to furnish available potassium and magnesium, and for a few years such use of kainit may be profitable on lands deficient in organic matter, but the evidence thus far secured indicates that its use is not absolutely necessary and that it will not be profitable after adequate provision is made for supplying decaying organic matter, since this will necessitate returning to the soil the potassium contained in the crop residues from grain farming or the manure produced in live-stock farming, and will also provide for the liberating of potas- sium from the soil. (Where hay or straw is sold, manure should be bought.) On soils which are subject to surface washing, including especially the yellow silt loam of the upland timber area, and to some extent the yellow-gray silt loam and other more rolling areas, the supply of minerals in the subsurface and subsoil (which gradually renew the surface soil) tends to provide for a low-grade system of permanent agriculture if some use is made of legume plants, as in long rotations with much pasture, because both the minerals and nitrogen are thus provided in some amount almost permanently; but where such lands are farmed under such a system, not more than two or three grain crops should be grown during a period of ten or twelve years, the land being kept in pasture most of the time; and where the soil is acid a liberal use of limestone, as top- dressings if necessary, and occasional reseeding with clovers will benefit both the pasture and indirectly the grain crops. Advantage of Crop Rotation and Permanent Systems It should be noted that clover is not likely to be well infected with the clover bacteria during the first rotation on a given farm or field where it has not been grown before within recent years ; but even a partial stand of clover the first time will probably provide a thousand times as many bacteria for the next clover crop as one could afford to apply in artificial inoculation, for a single root-tubercle may contain a million bacteria developed from one during the sea- son’s growth. This is only one of several advantages of the second course of the rotation over the first course. Thus the mere practice of crop rotation is an advantage, especially in helping to rid the land of insects and foul grass and weeds. The clover crop is an advantage to subsequent crops because of its deep-rooting char- 48 Soil Report No. 10 L May, actcristic. The larger applications of organic manures (made possible by the larger crops) are a great advantage ; and in systems of permanent soil improve- ment, such as are here advised and illustrated, more limestone and more phos- phorus are provided than are needed for the meager or moderate crops pro- duced during the first rotation, and consequently the crops in the second rota- tion have the advantage of such accumulated residues (well incorporated with the plowed soil) in addition to the regular applications made during the second rotation. Tli is means that these systems tend positively toward the making of richer lands. The ultimate analyses recorded in the tables give the absolute invoice of these Illinois soils. They show that most of them are positively deficient only in limestone, phosphorus, and nitrogenous organic matter ; and the accumulated information from careful and long-continued investigations in different parts of the United States clearly establishes the fact that in general farming these essen- tials can be supplied with greatest economy and profit by the use of ground nat- ural limestone, very finely ground natural rock phosphate, and legume crops to be plowed under directly or in farm manure. On normal soils no other applica- tions are absolutely necessary, but, as already explained, the addition of some soluble salt in the beginning of a system of improvement on some of these soils produces temporary benefit, and if some inexpensive salt, such as kainit, is used, it may produce sufficient increase to more than pay the added cost. The Potassium Problem As reported in Illinois Bulletin 123, where wheat has been grown every year for more than half a century at Rothamsted, England, exactly the same increase was produced (5.6 bushels per acre), as an average of the first 24 years, whether potassium, magnesium, or sodium was applied, the rate of application per annum being 200 pounds of potassium sulfate and molecular equivalents of magnesium sulfate and sodium sulfate. As an average of 60 years (1852 to 1911), the yield of wheat was 12.7 bushels on untreated land and 23.3 bushels where 86 pounds of nitrogen and 29 pounds of phosphorus per acre per annum were applied. As further additions, 85 pounds of potassium raised the yield to 31.3 bushels; 52 pounds of magnesium raised it to 29.2 bushels ; and 50 pounds of sodium raised it to 29.5 bushels. Where potassium was applied, the wheat crop removed an- nually an average of 40 pounds of that element in the grain and straw, or three times as much as would be removed in the grain only for such crops as are suggested in Table A. The Rothamsted soil contained an abundance of lime- stone, but no organic matter was provided except the little in the stubble and roots of the wheat plants. On another field at Rothamsted the average yield of barley for 60 years (1852 to 1911) was 14.2 bushels on untreated land, 38.1 bushels where 43 pounds of nitrogen and 29 pounds of phosphorus were applied per acre per annum; while the further addition of 85 pounds of potassium, 19 pounds of magnesium, and 14 pounds of sodium (all in sulfates) raised the average yield to 41.5 bushels. Where only 70 pounds of sodium were applied in addition to the nitrogen and phosphorus, the average was 43.0 bushels. Thus, as an average of 60 years, the use of sodium produced 1.8 bushels less wheat and 1.5 bushels 1915 ] McLean County 49 more barley than the use of potassium, with both grain and straw removed and no organic manures returned. In recent years the effect of potassium is becoming much more marked than that of sodium or magnesium, on the wheat crop ; but this must be expected to occur in time where no potassium is returned in straw or manure, and no pro- vision made for liberating potassium from the supply still remaining in the soil. If the wheat straw, which contains more than three-fourths of the potassium removed in the wheat crop (see Table A), were returned to the soil, the neces- sity of purchasing potassium in a good system of farming on such land would be at least very remote, for the supply would be adequately maintained by the actual amount returned in the straw, together with the additional amount which would be liberated from the soil by the action of decomposition products. While about half the potassium, nitrogen, and organic matter, and about one-fourth the phosphorus contained in manure is lost by three or four months’ exposure in the ordinary pile in the barn yard, there is practically no loss if plenty of absorbent bedding is used on cement floors, and if the manure is hauled to the field and spread within a day or two after it is produced. Again, while in average live-stock farming the animals destroy two-thirds ‘of the or- ganic matter and retain one-fourth of the nitrogen and phosphorus from the food they consume, they retain less than one-tenth of the potassium ; so that the actual loss of potassium in the products sold from the farm, either in grain farming or in live-stock farming, is wholly negligible on land containing 25,000 pounds or more of potassium in the surface 6% inches. The removal of one inch of soil per century by surface washing (which is likely to occur wherever there is satisfactory surface drainage and frequent cul- tivation) will permanently maintain the potassium in grain farming by re- newal from the subsoil, provided one-third of the potassium is removed by crop- ping before the soil is carried away. From all these facts it will be seen that the potassium problem is not one of addition but of liberation ; and the Rothamsted records show that for many years other soluble salts have practically the same power as potassium to increase crop yields ill the absence of sufficient decaying organic matter. Whether this action relates to supplying or liberating potassium for its own sake, or to the power of the soluble salt to increase the availability of phosphorus or other ele- ments, is not known, but where much potassium is removed, as in the entire crops at Rothamsted, with no return of organic residues, probably the soluble salt functions in both ways. As an average of 112 separate tests conducted in 1907, 1908, 1909, and 1910 on the Fairfield experiment field, an application of 200 pounds of potassium sulfate, containing 85 pounds of potassium and costing $5.10, increased the yield of corn by 9.3 bushels per acre ; while 600 pounds of kainit, containing only 60 pounds of potassium and costing $4, gave an increase of 10.7 bushels. Thus, at 40 cents a bushel for corn, the kainit paid for itself ; but these results, like those at Rothamsted, were secured where no adequate provision had been made for decaying organic matter. Additional experiments at Fairfield included an equally complete test with potassium sulfate and kainit on land to which 8 tons per acre of farm manure 50 Soil Report No. 10 [May, were applied. As an average of 112 tests with each material, the 200 pounds of potassium sulfate increased the yield of corn by 1.7 bushels, while the 600 poundc of kainit also gave an increase of 1.7 bushels. Thus, where organic manure was supplied, very little effect was produced by the addition of either 1 potassium sulfate or kainit ; in part perhaps because the potassium removed in the crops is mostly returned in the manure if properly cared for, and perhaps in larger part because the decaying organic matter helps to liberate and hold in solution other plant-food elements, especially phosphorus. In laboratory experiments at the Illinois Experiment Station, it has been shown by chemical analysis that potassium salts and most other soluble salts increase the solubility of the phosphorus in soil and in rock phosphate; also that the addition of glucose with rock phosphate in pot-culture experiments increases the availability of the phosphorus, as measured by plant growth, altho the glucose consists only of carbon, hydrogen, and oxygen, and thus contains no plant food of value. If we remember that, as an average, live stock destroy two-thirds of the or- ganic matter of the food they consume, it it easy to determine from Table A that more organic matter will be supplied in a proper grain system than in a strictly live-stock system ; and the evidence thus far secured from older experiments at the University and at other places in the state indicates that if the corn stalks, straw, clover, etc., are incorporated with the soil as soon as practicable after they are produced (which can usually be done in the late fall or early spring), there is little or no difficulty in securing sufficient decomposition in our humid climate to avoid serious interference with the capillary movement of the soil moisture, a common danger from plowing under too much coarse manure of any kind in the late spring of a dry year. If, however, the entire produce of the land is sold from the farm, as in hay farming or when both grain and straw are sold, of course the draft on potas- sium will then be so great that in time it must be renewed by some sort of appli- cation. As a rule, farmers following this practice ought to secure manure from town, since they furnish the bulk of the material out of which manure is pro- duced. Calcium and Magnesium When measured by the actual crop requirements for plant food, magnesium and calcium are more limited in some Illinois soils than potassium. But with these elements we must also consider the loss by leaching. As an average of 90 analyses 1 of Illinois well-waters drawn chiefly from glacial sands, gravels, or till, 3 million pounds of water (about the average annual drainage per acre for Illinois) contained 11 pounds of potassium, 130 of magnesium, and 330 of cal- cium. These figures are very significant, and it may be stated that if the plowed soil is well supplied with the carbonates of magnesium and calcium, then a very considerable proportion of these amounts will be leached from that stratum. Thus the loss of calcium from the plowed soil of an acre at Rothamsted, England, where the soil contains plenty of limestone, has averaged more than 300 pounds a year as determined by analyzing the soil in 1865 and again in 1905. Prac- tically 'the same amount of calcium was found, by analyses, in the Rothamsted drainage waters. ‘Reported by Doctor Bartow and associates, of the Illinois State Water Survey. 1915 ] McLean County 51 Common limestone, which is calcium carbonate (CaC0 3 ), contains, when pure, 40 percent of calcium, so that 800 pounds of limestone are equivalent to i 320 poupds of calcium. Where 10 tons per acre of ground limestone were K applied at Edgewood, Illinois, the average annual loss during the next ten years amounted to 790 pounds per acre. The definite data from careful investigations seem to be ample to justify the conclusion that where limestone is needed at least 2 tons per acre should be applied every 4 or 5 years. It is of interest to note that thirty crops of clover of four tons each would require 3,510 pounds of calcium, while the most common prairie land of southern Illinois contains only 3,420 pounds of total calcium in the plowed soil of an acre. (See Soil Report No. 1.) Thus limestone has a positive value on some soils for the plant food which it supplies, in addition to its value in correcting soil acidity and in improving the physical condition of the soil. Ordinary lime- stone (abundant in the southern and western parts of the state) contains nearly 800 pounds of calcium per ton; while a good grade of dolomitic limestone (the ’ more common limestone of northern Illinois) contains about 400 pounds of cal- I cium and 300 pounds of magnesium per ton. Both of these elements are fur- | nished in readily available form in ground dolomitic limestone. In the management of most soil types, one very important thing, aside from proper fertilization, tillage, and drainage, is to keep the soil in good physical condition, or good tilth. The constituent most important for this purpose is organic matter. Not only does it impart good tilth to the soil, but it prevents I much loss by washing on rolling land, warms the soil by absorption of heat, re- I tains moisture during drouth and prevents the soil from running together badly ; and, as it decays, it furnishes nitrogen for the crop and aids in the liberation of mineral plant food. This constituent must be supplied to the soil in every prac- tical way, so that the amount may be maintained or even increased. It is being broken down during a large part of the year, and th^ nitrates produced are used for plant growth. This decomposition is necessary, but it is also quite necessary that the supply be maintained. The physical effect of organic matter in the soil is to produce a granulation, or mellowness, very favorable for tillage and the development of plant roots. If continuous cropping takes place, accompanied with the removal or the destruc- tion of the corn stalks and straw, the amount of organic matter is gradually diminished and a condition of poor tilth will ultimately follow. In many cases this already limits the crop yields. The remedy is to increase the organic-matter content by plowing under manure or crop residues, such as corn stalks, straw, and clover. Selling these products from the farm, burning them, or feeding them and not returning the manure, or allowing a very large part of the manure to be lost before it is returned to the land, all represent bad practice. One of the chief sources of loss of organic matter in the corn belt is the practice of burning the corn stalks. Could the farmers be made to realize how great a loss this entails, they would certainly discontinue the practice. Probably 1 no form of organic matter acts more beneficially in producing good tilth than corn stalks. It is true that they decay rather slowly, but it is also true that their Physical Improvement of Soils Soil Report No. 10 [ Man r 52 durability in the soil after partial decomposition is exactly what is needed in the maintenance of an adequate supply of humus. The nitrogen in a ton of corn stalks is iy 2 times that in a ton of manure, and a ton of dry corn stalks incorporated with the soil will ultimately furnish as much humus as 4 tons of average farm manure; but when burned, both the humus-making material and the nitrogen which these stalks contain are de- stroyed and lost to the soil. The objection is often raised that when stalks are plowed under they inter- fere very seriously in the cultivation of corn, and thus indirectly destroy a great deal of corn. If corn stalks are well cut up and then turned under to a depth of 5^2 to 6 inches when the ground is plowed in the spring, very little trouble will result. Where corn follows corn, the stalks, if not needed for feeding purposes, should be thoroly cut up with a sharp disk or stalk cutter and turned under. Likewise, the straw should be returned to the land in some practical way, either directly or as manure. Clover should be one of the crops grown in the rotation, and it should be plowed under directly or as manure instead of being sold as hay, except when manure can be brought back. It must be remembered, however, that in the feeding of hay, or straw, or corn stalks, a great destruction of organic matter takes place, so that even if the fresh manure were returned to the soil, there would still be a loss of 50 to 70 percent owing to the destruction of organic matter by the animal. If manure is allowed to lie in the farmyard for a few weeks or months, there is an additional loss which amounts to from one-third to two-thirds of the manure recovered from the animal. This is well shown by the results of an experiment conducted by the Maryland Experiment Station, where 80 tons of manure were allowed to lie for a year in the farmyard and at the end of that time but 27 tons remained, entailing a loss of about 66 percent of the manure. Most of this loss occurs within the first three or four months, when fermentation, or ‘ ‘ heating, ’ ’ is most active. Two tons of manure were exposed from April 29 to August 29, by the Canadian Experiment Station at Ottawa. During these four months the organic matter was reduced from 1,938 pounds to 655 pounds. To obtain the greatest value from the manure, it should be applied to the soil as soon as possible after it is produced. It is a common practice in the corn belt to pasture the corn stalks during the winter and often rather late in the spring after the frost is out of the ground. This tramping of stock sometimes puts the soil in bad condition for working. It becomes partially puddled and will be cloddy as a result. If tramped too late in the spring, the natural agencies of freezing and thawing, and wetting and drying, with the aid of ordinary tillage, fail to produce good tilth before the crop is to be planted. Whether the crop is corn or oats, it neces- sarily suffers, and if the season is dry, much damage may result. If the field is put in corn, a poor stand is likely to follow, and if put in oats, a compact soil is formed which is unfavorable for their growth. Sometimes the soil is worked when too wet. This also produces a partial puddling which is unfavorable to physical, chemical, and biological processes. The bad effect will be greater if cropping has reduced the organic matter below the amount necessary to maintain good tilth.