Q.630.7 U 6sr no, 70 cop, 5 WARREN COUNTY SOILS I ■ NOTICE: Return or renew all Library Materials! The Minimum Fee (or each Lost Book Is $50.00. The person charging this material is responsible for its return to the library from which it was withdrawn on or before the Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for discipli- nary action and may result in dismissal from the University. To renew call Telephone Center, 333-8400 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN SEP 3 19» L16I — O-I096 I Digitized by the Internet Archive in 2011 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/warrencountysoil70wasc +**& ,„.-,.... WARREN COUNTY SOILS By HERMAN WASCHER and R. S. SMITH Soil Report No. 70 UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Urbana, Illinois October, 1941 STATE ADVISORY COMMITTEE ON SOIL INVESTIGATIONS 1940-1941 C. W. Holmes, Edelstein G. A. Lazier, Rochelle W. W. McLaughlin, Decatur W. E. Riegel, Tolono RESEARCH AND TEACHING STAFF IN SOILS 1940-1941 H. P. Rusk, Director of the Experiment Station W. L. Burlison, Head of Agronomy Department Soil Physics and Mapping R. S. Smith, Chief D. C. Wimer, Associate Chief Herman Wascher, Assistant Chief J. E. Gieseking, Assistant Chief R. S. Stauffer, Assistant Chief G. D. Smith, Associate F. F. Riecken, Associate E. P. Whiteside, Associate R. T. Odell, First Assistant T. G. Pearse, Assistant J. B. Fehrenbacher, Assistant J. S. McVickar, Assistant Soil Fertility and Analysis E. E. DeTurk, Chief F. H. Crane, Associate Chief R. H. Bray, Assistant Chief J. C. Anderson, First Assistant I. R. Hoener, First Assistant S. R. Dickman, First Assistant L. T. Kurtz, Assistant S. W. Melsted, Assistant Soil Experiment Fields F. C. Bauer, Chief H. J. Snider, Assistant Chief A. L. Lang, Assistant Chief C. J. Badger, Associate L. B. Miller, Associate C. H. Farnham, First Assistant P. E. Johnson, First Assistant L. F. Marriott, Assistant M. H. Nelson, Assistant Soil Biology O. H. Sears, Chief M. D. Appleman, First Assistant Soils Extension C. M. Linsley, Assistant Professor E. D. Walker, Associate Soil Survey Publications R. S. Smith, Chief Julia A. Franklin, Assistant C. H. Simonson, Assistant "It must be remembered that the productive power of the soil is the basic support of all prosperity." — C. G. HOPKINS "It is the duty of every landowner to see that his land when he leaves it is as good or better than when he received it."— j. G. mosier INTRODUCTORY NOTE IT IS A MATTER of common observation that soils vary tre- mendously in their productive power, depending upon their physi- cal condition, their chemical composition, and their biological activities. For an) comprehensive plan of soil improvement looking toward the permanent maintenance of our agricultural lands, a definite knowledge ■ it the various existing kinds or types of soil is a first essential. It is the purpose of a soil survey to classif) the various kinds of soil of a given area in such a manner as to permit definite characterization for description and for mapping. With the information that Mich a survey affords, every farmer or landowner of the surveyed area has at hand the basis for a rational system for the improvement of his land. At the same time the Experiment Station is furnished a scientific inventory ■ if the soils of the state; and with such an inventory as a basis it can proceed intelligently to plan those fundamental investigations so neces- sary for the solution of problems of practical soil improvement. This county soil report is one of a series reporting the results ol the sod sur\e\ which, when completed, will cover the stale of Illinois. Each county report is intended to he as nearly complete in itself as it is practicable to make it, even at the expense of some repetition. While the authors must assume the responsibility for the presenta tion of this report, it should he understood that the material for it represents the contribution of a considerable number of the present and former members of the Agronomy Department working in their respective lines of soil mapping, soil analysis, and experiment field investigation. hT i CONTENTS PAGE GEOGRAPHICAL AND HISTORICAL FEATURES 3 Agricultural Production 4 Climate 5 Topography and Drainage 6 FORMATION OF WARREN COUNTY SOILS 7 Origin of Soil Material 7 How the Soils Were Developed 8 SOIL CLASSIFICATION AND MAPPING 10 GENERAL SUGGESTIONS FOR SOIL IMPROVEMENT 11 SOIL TYPES OF WARREN COUNTY: THEIR USE, CARE AND MANAGEMENT 14 Hickory gravelly loam, eroded 14 Berwick silt loam 15 Clinton silt loam 16 Tama silt loam 18 Muscatine silt loam 19 Grundy silt loam 21 Monmouth silt loam 22 Denny silt loam 22 Kern silt loam, terrace 23 Grundy clay loam 23 Harpster clay loam 24 Huntsville loam, bottom 25 Alexis silt loam, terrace 26 Littleton silt loam, terrace 26 Swan clay loam, bottom 26 Camden silt loam, terrace 26 Hersman silt loam, terrace «. 27 Hersman clay loam, terrace 27 PRODUCTIVITY OF WARREN COUNTY SOILS 27 SUMMARY OF CHARACTERISTICS OF WARREN COUNTY SOILS 28 ALPHABETICAL INDEX TO SOIL TYPES 30 WARREN COUNTY SOILS l!> Herman Wascheh and R. S. Smith 1 GEOGRAPHICAL AND HISTORICAL FEATURES ARREN O >UNTY lies in the western pari of Illinois on the drain- age divide between the Mississippi and Illinois rivers, li is rectangu- lar in shape about 18 miles from east to west and 30 miles from north to south and occupies an area of approximately 535 square miles. It was established by legislative act January 13, 1825, and was named in honor of Joseph K. Warren, a general in the Revolutionary War. The first permanent settlements in the county were made in the spring of 1828 along Henderson creek in Kelly township. Within two years the population had increased to 308, which was sufficient for a commission to he appointed to choose a 28 24 20 ie — / WARREN COUNTY POPULATION 1830 184.0 1850 1860 1870 1880 1900 1910 1920 1930 1940 Fic, 1. Popui \iin\ Trend i\ Warren County The rapid increase in population in Warren county from 1830 to 1870 is typical <>i many Illinois counties, but the decline during the later decades lias not been so marked as in many i .tin t counties. site for the county courthouse. This commission chose a portion of Section 29, Monmouth township, because it seemed to he nearest the center of population; and Monmouth, now the principal city as well as the count}- seat, was built around this site. In later years Monmouth was often called the "Maple City" because of the large number of maple trees lining its streets. When first established, Warren count)- also included the territory that is now Henderson county. But when a difference of opinion arose over the permanent location of the courthouse, the settlers in the western half of the county organized ■Herman Wascher, Assistant Chief in Soil Survey; and R. S. smith. Chief in Soil Physics and Soil Survey. Soil Report No. 70 October, a separate government. This was recognized by the state in 1841, when Hender- son county was formed. According to the U. S. Census, the population of Warren county increased rapidly following the close of the Black Hawk War, until by 1870 there was a total of 23,200 inhabitants. Since that time the number has remained relatively constant, fluctuating between 21,300 and 23,300 (Fig. 1). Facilities for the marketing of agricultural products are well established in this part of the state. Direct routes by railroad are available to Kansas City and Chicago and to other important points in Missouri, Iowa, and Illinois. No farm 150 120 < z < O90 M O Z < o I f- 30 DAIRY CATTLE OTHER CATTLE SHEEP HORSES AND MULES I . I SWINE WARREN COUNTY LIVESTOCK 1880 1890 1900 1910 1920 1930 1940 Fig. 2. — Production of Principal Classes of Livestock in Warren County For the past sixty years the production of livestock has fluctuated within rather narrow limits. Two exceptions are a notable increase in the number of sheep in 1940 and a con- sistent decline since 1910 in the number of horses and mules. in the county is more than 8 miles from a paved highway. 1 Considerable progress has been made since 1932 in the improvement of tributary country roads, so that at the present time most of the county is fairly well supplied by some form of all-weather road. Agricultural Production- Agriculture is the chief source of economic wealth in Warren count)'. The principal crops grown and the principal livestock products marketed are those 'Subsequent to the printing of the soil map for Warren county, Route 94A was changed to 164; Nos. 94B and 3 were changed to 135; and No. 124 was changed to 116. 2 A11 crop and livestock statistics are from either the U. S. Census or Illinois Crop and Livestock Statistics, Illinois Crop Reporting Service, Illinois Department of Agriculture co- operating with the U. S. Department of Agriculture. 1941 1 Warn n Counts 5 common to the corn belt. Corn is the major crop both in acreage and in value, hut wheat, oats, soybeans, and hay are also important. For the fifteen- year period 1924 1938 inclusive the average yearly acreage of the important crops was as follows: corn 126,800 acres; oats 44,000 acres; hay 27,700 acres; soybeans 8,200 acres; wheat 7,900 acres; sweet clover 2,700 acres, and alfalfa 1,500 acres. The acreages of all crops except wheat and soybeans have remained relatively stable thruout this fifteen-year period. Wheat, however, declined from 21,200 acres in 1 ( >24 to 7.100 aires in 1938, while the soybean acreage increased from less than 1.000 acres in 1927 to 14,200 acres in 1938. According to the U. S. Census, there were 271,171 acres of land in Warren county available for crops in 1030. ( )f this amount 199,646 acres were harvested, of which 107,601 acres, or 53. S percent, were harvested by tenant farmers. There were- 68,600 acres of original forest area in Warren county, but only 9,905 acres remained as woodland in 1934. Some idea of the trend in livestock production may be gained from Fig. 2, in which the numbers of cattle, sheep, horses and mules, and swine are graphically presented by ten-year intervals beginning with 1880. Altho the number of dairy cattle decreased about 13 percent from 1020 to 1939, milk production remained nearly constant at about 4 million gallons a year. Poultry and egg production have also brcii an important source of farm income, as indicated by the fact that nearly a million dozen eggs were produced in 1030. Fruit and vegetable production is of minor importance in Warren count}-. Climate The climate of Warren county is representative of that prevailing in the north- central United States. It is characterized by a wide range in temperature between the extremes of winter and summer and by an irregularly distributed but rela- tively abundant rainfall. In the following paragraphs certain temperature, frost, and rainfall data are presented which are based on records of the Monmouth Weather Station for the twenty-five years, 1915 to 1939, inclusive. The mean summer temperature during this period was 73.2° F., the mean winter temperature was 29.6° F., and the average mean yearly temperature was 51.1' F. The highest temperature recorded was 110 F. in July, 1936, and the lowest -22° F. in January and December, 1924. The average date of the last killing frost in the spring, according to these records, is April 27. the date of the first killing frost in the fall October 13. This gives an average frost-free season of 100 days, which ordinarily provides ample time for the corn crop to reach maturity. The latest recorded killing frost in the spring was on May 2?, 1025, and the earliest in the fall was on September 20, 1918. The shortest growing season, 138 days, occurred in 1925. The longest growing season, 108 days, was in 1938. The average annual precipitation at Monmouth for this same twenty-five-year period was 35.83 inches. This includes the water melted from an average annual snow tall of 25 inches, about 10 inches of snow being equivalent to an inch of rainfall. The driest year in this period was 1030, when the total precipitation was 25.0 inches: 1929 was the wettest year, with 40.9 inches. The driest month, on the average, was February, with precipitation of only 1.38 inches. June and Sep- 6 Soil Report No. 70 [October, tember were the wettest months, with an average of 5.16 inches and 4.11 inches respectively ; while April, May, July, and August all averaged 3 inches or more. The above average figures would seem to indicate adequate rainfall thruout the growing season, April thru September ; but the fact is that rainless periods of sufficient length to be harmful occur at rather frequent intervals. During the above-mentioned twenty-five-year period there were 51 rainless periods of 21 days or more during the growing season, according to data from the Monmouth Weather Station. A rainless period, as the term is used in this report, is one in which no rain totaling more than 1/2 inch falls during any 24 hours. Of these 51 rainless periods 25 exceeded 30 clays, while one in 1920 lasted 86 days and another in 1936 lasted 83 days. When 30 days or more elapse without rain during a critical period of crop growth, some injury is likely to result. This is especially true on soils low in organic matter and having a low water-holding capacity. Rainless periods of less than 21 days probably do little permanent harm, especially on the more pro- ductive soils, tho corn and even oat crops are known to have been damaged by rainless periods of as short duration as three weeks when accompanied by several days of dry hot winds. Thus neither the total monthly nor total yearly precipitation is a good index to the amount of available moisture that may be present in the soil at any specific time — departures from the average are too frequent and too wide. Furthermore the rate of precipitation, rate of evaporation, absorptive and retentive capacity of the soil, as well as other soil characteristics and certain plant characteristics, are important factors influencing the amount of moisture available. Topography and Drainage The prevailing topography of Warren county is essentially that of a flat plain which has been fairly well dissected by the headwater erosion of numerous streams and small drainage lines. It is only in the northern and the extreme southern parts of the county that remnants of a few distinct ridges occur which are not directly related to stream erosion. Those in the northern end of the county are already partially obliterated by the uneven topography along Henderson and Cedar creeks. Much of the northwestern and southeastern portions of Warren county are so strongly dissected that little of the original flat plain remains. Here surface drainage is fairly rapid, for the most part, and artificial drainage plays a minor role in the removal of excess water. Thru the central part of the county, however, and particularly in the southwestern portion, many areas of flat land remain which must be provided with artificial drainage if farming operations are to be carried on successfully. The lowest points in Warren county are the Henderson creek and Cedar creek bottoms at the Henderson county border, which are 579 feet above sea level. The highest point is an elevation of 801 feet near Colfax school in Point Pleasant township. Thus the maximum range in relief for the county is 222 feet. In the dissected areas, however, the general range is from about 600 feet in the bottomlands to about 720 feet at the margins of the flat tablelands, while the height of the tablelands varies from about 730 to 780 feet. V'll\ WARRI \ < "ur\ n 7 FORMATION OF WARREN COUNTY SOILS Origin of Soil Material The nature of Warren county soils can be more readily understood it' some- thing is known of the formation and composition of the materials from which they have been derived. The upland and terrace soils have developed from ma- terials deposited during and immediately following glacial times, while the bottom- land sediments have been reworked and more or less assorted, and deposited by the streams during recent times. The Glacial Epoch was marked by several changes in climate. During the colder intervals snow and ice accumulated in the northern parts of the conti- nent in such vast quantities that pressure developed in the masses caused them to push outward from their centers of accumulation, forming glaciers. The glaciers, aided by further accumulations of snow and ice at their margins, moved south ward until the temperature was such that the ice melted rapidly enough to stop further progress. The tremendous force exerted by the advancing ice gouged out basins, leveled oil hills, and tilled in valleys, and thus often completely obliterated the former features of the surface over which the glacier passed. The mixed rock debris, part of which existed before the advance of the glacier and part of which was formed by its advance, was gathered up and sometimes carried for hundreds ol miles. When a warmer period occurred, the ice melted, and the rock frag- ments and other debris, much of which had been ground very line, were deposited over the areas which the ice occupied. This rock debris is called "glacial till" or simply "till." There were four great periods during which ice sheets moved down from the north. These movements were separated by long intervals (hiring which the climate was warm enough for the country to become clothed with vegetation. The third advance n\ the ice, called the Illinoian, covered all the area that is now Warren count)-, and upon melting back, left a broad and relatively level till plain which, together with subsequent erosion, was largely responsible for the present surface topography. During the succeeding warm interval the till was leached of its lime to a depth of several feet, and the upper portion was weathered into soil. This old soil and leached till may be readily identified in man}- of the deep cuts made by road and railroad workers and by streams. The ice of the fourth and last movement, called the Wisconsin, did not touch any pari of Warren county, yet its presence in the near northern regions was of tremendous importance, as it was the source of the material from which the soils of the county were formed. As the ice of the Wisconsin glacier melted, immense quantities of water, carrying clay, silt, sand, and often gravel, poured out over the flat lands jusl beyond the glacier front and down the stream channels. Where- ever the velocity of the water was checked, the load of sand and gravel was dropped, and the resulting deposits formed the present outwash plains and stream terraces. Much of the silt was deposited on the broad bottomland tlats of the Illinois and Mississippi rivers, while most of the clay was carried to the lower Mississippi valley and into the Gulf of Mexico. It was these silt tlats, particularly those along the Mississippi river in the neighborhood of Mercer and Henderson 8 Soil Report No. 70 [October, counties, that became the source of the material from which the present soils of Warren county were derived. Presumably each winter when low temperatures checked the melting of the ice sheet, the Hoodwaters receded, exposing the large silt flats. As soon as these flats were dry, the wind picked up the silty sediment and carried it onto the upland, burying the weathered till and its old soils and forming new deposits of uniformly textured material called "loess." No doubt other sources have con- tributed small quantities of material to these loess deposits, as the dust storms of 1934 suggest (Fig. 3). On the nearly level areas in Warren county, where erosion has been negli- gible, the loessial material averages about 10 feet thick, varying from about 12 Fig. 3. — Loess in the Making The upland soils of Warren county owe their productivity largely to the silty wind- blown material called loess, which was deposited near the close of the ice age by dust storms similar to the one pictured above. In this county the Mississippi river bottom was the source of most of the dust. This picture was taken in Texas in the spring of 1935. (Courtesy U. S. Soil Conservation Service) feet in the northwestern part of the county to about 9 feet in the southeastern part. On slopes where erosion has been active, however, the loess is considerably thinner and in some places is entirely absent, so that the leached Illinoian till is exposed. From the weathered loess, including the small areas of exposed till, and the terrace and bottomland sediments, the present soils of Warren county have been developed, and these materials are known as the "parent materials" of the soils of Warren county. How the Soils Were Developed When first deposited, the unweathered loess was grayish or pale yellowish in color, silty in texture, of an open porous nature, high in lime content, and amply supplied with the mineral elements of plant food. As weathering forces ( oxidation, solution, decomposition, and others) attacked the minerals of the loess, /W/| \\ vrri m Counts 9 plant-food compounds were liberated and vegetation spread over the land. With the passage of time this weathering action gradually leached away the free lime, or calcium carbonate, and reduced portions of the sill particles to clay. Thus the process of soil development was begun. The weathering forces acted differently from place to place because of dif- ferences in the slope of the land surface, drainage, type of incoming vegetation, and other factors. As a result, the products formed, which we call soils, began to show differences. As the weathering continued, these differences became more and more pronounced until finally soils with distinctly unlike characteristics were evolved. These dissimilar soils are called "soil types." In their early stages of development, soil types are strongly under the influence of their parent materials; their distinguishing features are not clearly defined and they are said to he young. As weathering progresses, the characteristics of the different soil types become more clearly defined and the soils are said to he pro- gressing toward maturity and eventually to old age. Most of the soils in Warren count}- probably would he classed as youthful or in early maturity. If there were any types derived from the leached Illinoian till, they would ordinarily be classified as well advanced or rather old. but the exposed areas of this material are all subject to severe erosion and so do not show an}' definable soil features. Three types of vegetation— deciduous forest, prairie, and marsh or swamp- exerted important influence on the soils of Warren county during the time they were developing. Forest vegetation produces a thin accumulation of leaf and twig litter on the surface of the soil; this litter is exposed to the air and therefore decays rather rapidly and completely, supplying little organic matter to the soil. Moreover the roots of trees are coarse, penetrate deeply, and are relatively few in number. As compared with grass roots, the\' add little to the supply of organic matter when they decay. The soils in this county that have developed under a forest cover are therefore low in organic matter; and their surfaces are usually grayish or yellowish in color. The grass vegetation of the prairies, on the other hand, produces enormous quantities of fibrous roots which are mostly concentrated in the upper 12 to 18 inches of the soil. Because air does not move freely thru the soil, these roots decay slowly, and when the\' are decomposed, portions of the residue tend to be pre- served for a long period. Since the incorporation of organic matter in the soil produces a dark color, the grassland soils have brownish surface strata. Marsh vegetation also produces large quantities of fibrous roots. The low- lying pondlike nature of marsh areas is conducive to a more or less permanently high water table which greatly retards the entrance of oxygen, thus slowing up or preventing complete decomposition of the organic matter, dims immense ac- cumulations of organic matter were preserved in the wet areas of the flat prairies, and the surface strata of these soils became dark brown to black. Differences in drainage are also responsible for the development of certain features peculiar to each soil type. Soil material in a depression where the water table remains at the surface much of the year develops characteristics distinctly different from those developed from the same material on a hill or in any oilier place where the water table remains several feet below the surface. Idle most obvious difference is in color. The poorly drained soil in the depression is gray 10 Soil Report No. 70 [October, because of lack of oxidation of the iron compounds, tho under marsh vegetation the gray color in the surface is sometimes completely hidden by the heavy ac- cumulation of organic matter. The soil developed under good drainage, on the other hand, is yellowish or reddish, tho again the color of the surface horizon is often modified by organic matter. For simplicity and ease of description, natural drainage is divided into surface drainage, which refers to surface runoff, and under drainage, which refers to the passage of water down thru the profile. Underdrainage is determined by the per- meability of the subsoil and underlying material. The relative conditions of surface drainage and underdrainage are designated by the terms excessive, rapid, moderate, and slow. In each case moderate stands for the best condition. Moder- ate surface drainage indicates satisfactory runoff, with little or no erosion ; moderate underdrainage indicates relatively free movement of excess ground water to tile but good retention of moisture for plant growth. In the humid, temperate climate of Illinois a pronounced effect of the weather- ing of soil material is the production of layers, or horizons, in the soil, each horizon having more or less definite characteristics. From a practical standpoint these various horizons can be described as surface, subsurface, and subsoil. The surface is usually the layer of greatest organic-matter accumulation and ordinarily is about plow depth in thickness, tho it varies considerably according to soil type. The subsurface in young soils is generally a zone of gradation between the surface and the subsoil ; but in old soils it may be a bleached, highly weathered layer, en- tirely different from either the overlying surface or the underlying subsoil. The subsoil is usually the zone of clay accumulation and consequently is more plastic or sticky than the surface or subsurface horizon above or the parent material below. This condition generally becomes more pronounced as the soils grow older. All these zones or horizons taken together constitute the "soil profile," and differences in arrangement, color, thickness, or any other of the various physical and chemical features of the respective horizons constitute the basis upon which soil types are differentiated and the soil map constructed. SOIL CLASSIFICATION AND MAPPING In the soil survey the "soil type" is recognized as the unit of classification. Each type has definite characteristics upon which its separation from other types is based. These characteristics are inherent in the strata or horizons which taken together constitute the soil profile. Failure to appreciate the fact that soil types are differentiated on the basis of the character of the entire profile and not on the surface alone often makes it difficult to understand exactly what is meant by the term "soil type." It frequently happens that the surface stratum of one type is no different from that of another, and yet the two types may differ widely in character as well as in agricultural value. It is of utmost importance, therefore, in studying descriptions of soil types to get a clear mental picture of all the outstanding features of each type. It is likewise important to understand that a given type must of necessity include a range in properties. The boundaries between soil types are seldom sharp, there frequently being a transitional area or zone which includes some of 1941] Warren ( !ouni v 11 the properties of each type. ( )ne of the most difficult problems of the soil sur- veyor is to determine the limits of variability in a given soil type. Besides the natural range in properties that is found within a given soil type, there are other variations that have been brought about by differences in the management of tin- soil since it has been under cultivation. For example, the pro- ductive capacity of a soil developed on rolling topography may be easily and permanently impaired by management practices which permit soil erosion to go unchecked. Differences of a temporary nature may be induced by poor rotations Tabu-: 1.— WARREN COUNTY SOILS: Areas of the Different Soil Types Type No. 8 17 18 36 41 43 44 45 51 65 67 73 80 81 107 134 139 195 Type name Hickory gravelly loam, eroded Berwick silt loam Clinton silt loam Tama silt loam Muscatine silt loam Grundy silt loam Monmouth silt loam Denny silt loam Kern silt loam, terrace Grundy clay loam Harpster clay loam Huntsville loam, bottom Alexis silt loam, terrace Littleton silt loam, terrace. . . . Swan clay loam, bottom Camden silt loam, terrace. . . . Hersman silt loam, terrace. . . . Hersman clay loam, terrace. . . Pond Total Area in square miles 10.75 10.12 83.85 152.27 165.96 41.05 3.60 .26 .38 21.87 .50 39 . 40 .63 1.31 .39 2.08 .25 .06 .06 534.79 Area in acres 6 880 6 480 53 660 97 450 106 220 26 270 2 300 170 240 14 000 320 25 220 400 840 250 1 330 160 40 40 342 270 Percent of total area 01 89 68 28.48 31.03 7.65 .67 .05 .07 4.09 .09 .38 .13 .25 .07 .39 .05 .01 .01 100.00 and other poor farming practices which lower the present productivity of the soil without necessarily impairing the potential or inherent productivity. A list of the soil types occurring in Warren county is given in Table 1, which shows also the area of each in square miles and in acres and the percentage that each constitutes of the total area of the county. There were 18 types mapped, of which six cover more than 94 percent of the area of the county. For the location and boundary of each soil type see the accompanying soil map. GENERAL SUGGESTIONS FOR SOIL IMPROVEMENT The following brief discussion of soil-improvement principles is intended to decrease the necessity for repetition in the Use and Management section under each soil type, since the basic principles of soil improvement are similar for many soils. These suggestions for soil improvement, together with the discus- sion of the productivity of Warren count}' soils (page 27), it is hoped will help every farmer in the county to maintain and improve the productivity of the soils 12 Soil Report No. 70 October, on his farm. The discussion is based on the assumption that adequate drainage has been established and that the principal cash crop is corn. Each soil type has a "productive level" for each crop. This level represents the average yield of a crop over a period oi years and under a specific set of conditions and will vary as management practices vary. Low crop yields do not in themselves necessarily indicate the need for a change in management practices, because some soils have physical limitations which hold the productivity low. Table 2.— WARREN COUNTY SOILS ^Average Yields to Be Expected Over a Period of Years Under Good Management (Figures in bold face are averages from Farm Bureau Farm Management Service records; others are estimated yields.) Type No. 17 18 36 41 43 44 45 51 65 67 73 80 81 107 134 139 195 Type name Hickory gravelly loam, eroded 1 . Berwick silt loam Clinton silt loam Tama silt loam Muscatine silt loam Grundy silt loam 3 Monmouth silt loam 3 . . Denny silt loam Kern silt loam, terrace. Grundy clay loam 3 Harpster clay loam Huntsville loam, bottom. . . Alexis silt loam, terrace. . . . Littleton silt loam, terrace. . Swan clay loam, bottom 3 . . . Camden silt loam, terrace. . Hersman silt loam, terrace. . Hersman clay loam, terrace. Open- polli- nated corn bu. 38 40 48 54 54 54 38 38 54 54 ( 4 ) 48 52 ( 4 ) 40 54 54 Oats bu. 34' 38 38 46 46 46 34 34 46 44 ( 4 ) 38 44 ( 4 ) 38 46 46 Winter wheat bu. 20 22 24 26 26 26 20 20 26 24 ( 4 ) 24 26 ( 4 ) 22 26 26 Soy- beans bu. 20 22 2 24 2 28 28 28 20 20 28 26 ( 4 ) 24 28 ( 4 ) 20 28 28 Alfalfa tons 2H 2% 1V2 W2 ( 4 ) 2H 2% ( 4 ) 2M 2% 2V 2 'Not adapted to cropping. 2 Crop not adapted without use of special erosion-control measures. 3 Soil-type name subsequently changed; see footnote under discussion of type. 4 Crops occasionally damaged by flooding. In normal years yields are about the same as for Grundy clay loam. But a difference between the average yields on a given farm and the productive level of the soil types under cultivation on that farm as shown in Table 2 does indicate need for a change in management practices, including changes in soil treatment. No soil, no matter how productive when first brought under cultivation, will maintain high yields of the grain crops for an indefinite time without the addition of certain materials. Yield records since 1887 on the Morrow plots show that when corn is grown continuously without soil treatment or catch crops, good yields are not maintained. These plots on the campus of the University of Illinois are located on soil similar in appearance and inherent productivity to Muscatine silt loam, a soil type which occurs extensively in Warren count)'. Liming. — If alfalfa, sweet clover, or red clover cannot be grown because of soil acidity, this condition should be corrected as the first step in soil improve- WARREN COUNTY SOIL MAP THE LOCATION of each soil type in Warren county is shown on this map, consisting of two sections, by a distinctive color and number. Where areas are too small to contain a number, the number is placed out- side the area and a line drawn from it to the area. About a mile south of Monmouth there are several small areas of Grundy clay loam that are shown in this way. To help in locating a particular farm or region, various other identifying features such as streams, roads, railroads, towns, and even rural resi- dences, schoolhouses, and churches are also indicated. For a description of each soil type and a statement of its best use and recommended management, see pages 14 to 28, consulting Contents, page 2, for exact page references. LEGEND Li 8 Hickory gravelly 1 17 Berwick silt loam u 18 Clinton silt loam 36 Tama silt loam K 41 Muscatine silt loe n ft K 43 Grundy silt loam 4 1 45 65 67 Monmouth silt loam Denny silt loam Kern silt loam, terrace Grundy clay loam Harpster clay loam 73 Huntsville loam, bottom 80 Alexis silt loam, terrace 81 Littleton silt loam, terrace 107 Swan clay loam 134 Camden silt loam, terrace 139 Hersman silt loam, terrace 195 Hersman clay loam, terrace CONVENTIONAL SIGNS ■ House • School house t Church 1 Store building Elevator , , , , Railroads (steam) , . , . Railroads (electric) ____= Paved Through Routes ^__^_ Metalled (all weather) roads ^ === Improved Dirt Roads .».._._ Secondary Dirt and Private Roads Township boundary lines County boundary lines Streams (flowing) "----" streams (intermittent) Lake or Pond «««* Rock outcrop Scale X X 1 I — I I =1 — 1!).?2 2 Miles 3 MKHCKK R. S Smith, In Charge Soil Survey E. A. Norton, Inspector NORTH SHEET COUNTY |IL SURVEY MAP OF WARREN COUNTY Ef TY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Soils Mapped by Herman Wascher, in Charge Eric Winters 44 LEGEND Hickory gravelly loam, eroded Berwick silt loam Clinton silt loam Tama silt loam Muscatine silt loam Grundy silt loam Monmouth silt loam 45 D enny silt loam Kern silt loam, terrace 67 73 Grundy clay loam Harpster clay loam Huntsville loam, bottom 80 Alexis silt loam, terrace Littleton silt loam, terrace 107 Swan clay loam, bottom 134 Camden silt loam, terrace Hersman silt loam, terrace 195 Hersman clay loam, terrace CONVENTIONAL SIGNS ■ House £ School house t Church I Store building -n — ► Elevator i i i i Railroads (steam) , , , Railroads (electric) , Paved Through Routes === Metalled (all weather) roads ^ ==== Improved Dirt Roads = === = = = Secondary Dirt and Private Roads Township boundary lines _ __ County boundary lines Streams (flowing) >""N..«*" Streams (intermittent) Lake or Pond hh Rock outcrop Scale X 'A 1 I — I I =i 1932 2 Miles R. S. Smith, In Charge Soil Survey E. A. Norton, Inspector COUNTY )IL SURVEY MAP OF WARREN COUNTY EI TY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Soils Mapped by Herman Wascher, in Charge Eric Winters 1941 | Vi \\est yields will be obtained by plowing under a stand of sweet clover at frequent intervals and adding phosphate and potash fertilizers when needed. Erosion Control. — Finally, the long-time effects of soil erosion must be given serious consideration even on moderately sloping land, it is essential in reducing erosion losses to keep a good cover of vegetation on the land as many months of the year as possible, but particularly during the winter and early spring. Since this cannot be done satisfactorily on poor soils, the application of limestone, phos- phate, and potash as needed must be part of any permanent erosion-control pro- gram for such soils. Suggestions for methods to use on specific soil types are given in the Use and Management paragraph under each type needing such pro- tection. More detailed information regarding erosion control will be found in Farmers' Bulletin 1795, "Conserving Corn-Belt Soils," published by the U. S. Department of Agriculture, Washington, D.C., and in Illinois Circular 513, "Save the Soil With Contour Farming and Terracing." SOIL TYPES OF WARREN COUNTY: THEIR USE, CARE AND MANAGEMENT A brief description of the outstanding characteristics of each soil type as mapped in Warren county, together with some general recommendations as to its use, care, and management, is given on the following pages. Some of this infor- mation is summarized in Table 3, page 29. The recommendations made for the management of the respective types are based on their requirements for the efficient production of the crops common to .the region. Such matters as the growing of special crops, the location of the land with respect to markets, and other economic considerations have not been taken into account. In order to outline a complete soil-improvement and management program for a single field or farm, it would be necessary to know not only what soil types are involved but also what cropping and management practices have been followed in the past as well as what type of farming is to be followed in the future. Obviously not all this information is available. The major purpose of this report is, therefore, to furnish such basic information about the various soil types as will enable a farmer to lay out his own program of management and improve- ment for the soils that occur on his farm. Hickory gravelly loam, eroded (8) Hickory gravelly loam, eroded, occurs on steep topography where the slope is greater than 15 percent. Such areas are commonly found along the stream /v// 1 \\ \kki n Counts 15 bluffs and deep gullies leading away from the bottomland. Tho not extensive, this type is important in various parts of the county, occupying a total area oi nearl) 1 1 square miles. In undisturbed foresl areas, where erosion lias remained at a minimum, there are sometimes thin soil horizons present. These usually include 2 to 3 inches of brownish-yellow sill loam surface with an occasional scattering of pebbles, 2 to 3 inches of yellowish subsurface, and 5 to 10 inches of reddish-yellow silty clay loam subsoil. Beneath the subsoil may be a layer of loess oi variable thickness, below which 1 it's leached pebbly till. However, any portion or all ol the soil horizons and siltv loess layers may have been removed by erosion and as a con- sequence the leached pebbly till, or in some cases even the underlying bedrock, may be exposed. Use and Management. The best use of Hickory gravelly loam, because it occurs on steep slopes and is easily damaged by erosion, is for timber and pasture. Slopes of less than M) to 40 percent may be used for permanent pasture provided overgrazing is avoided. ( )n areas already badly eroded or on slopes greater than 30 to 40 percent, plantings of hardy native trees such as oak, hickory, red cedar, and perhaps black locust, should be made. Black locust, while being the most suitable for erosion control, may be scriouslv damaged by borers. It should therefore be classed as a temporary vegetative cover, and trees of a more perma- nent nature should be planted as there is opportunity to do so. Interest in the preservation and increase of wildlife will suggest the planting of native shrubs and vines in gullies. This type of planting will not only help to control erosion but will also furnish food and cover for birds and wild animals. Berwick silt loam (17) Berwick sill loam is a light-colored soil that has developed under forest vege- tation on nearly level to undulating topography or where the slopes are not greater than 2 percent. It occurs in association with Clinton silt loam and covers a total area of about 10 square miles in Warren county. The surface is a brownish-gray to yellowish-gray silt loam 6 to 8 inches thick, low in organic matter, and strongly acid in reaction. In some areas the timbering has been rather light, and here the surface is darker, being more nearly a grayish brown. The subsurface is a pale yellowish-gray silt loam 6 to 8 inches thick. The subsoil is a yellowish-gray medium-plastic clay loam 12 to 18 inches thick. It breaks readily into Ji- to '4-inch subangular gray-coated aggregates. Beneath the subsoil the material is a permeable silt that becomes calcareous at a depth of '» to X feet. Small gritty brownish-black iron-manganese pellets occur in abun- dance on the surface and thruout the soil profile. These concretions are frequently called buckshot, and the land over which they are scattered is known locally as "buckshot land." Use (iiid Management. Berwick silt loam is not a highly productive soil tho satisfactory crop yields are often secured after its acidity has been corrected and barnyard or green manure has been applied. Those portions of the type that have slow surface drainage are also likely to have rather slow underdrainage, but for the most part drainage is not a serious problem. 16 Soil Report No. 70 [October, This soil produces good pasture following proper soil treatment. Without such treatment, however, results are often disappointing. Some areas which are now in standing timber may yield larger returns than if cleared. Circular 477, "Forest Planting on Illinois Farms," will be found very helpful in planning a manage- ment program for such areas. Clinton silt loam (18) Clinton silt loam is a light-colored soil that has developed under forest vege- tation on gently rolling to strongly rolling topography. It occurs generally as a Fig. 4. — A Gently Rolling Area of Clinton Silt Loam The good stand of corn on the right shows that this soil, altho not naturally very pro- ductive, can be so managed that it will yield well. Steeper slopes of Clinton should not be cultivated extensively because of the danger of erosion. belt of varying width bordering the eroded stream bluffs. It is one of the important types in the county, occupying a total area of nearly 84 square miles. In undisturbed areas where erosion has not been active, the surface is usually 5 to 7 inches thick and is a grayish-yellow silt loam low in organic matter and strongly acid in reaction. The subsurface is 4 to 7 inches thick and is a grayish- yellow to yellow silt loam. The subsoil is 12 to 18 inches thick and is a grayish- yellow to yellow medium-plastic silty clay loam which breaks into i/J.- to 1/2-inch rounded or nut-like aggregates. Beneath the subsoil the material is a permeable silt which is calcareous at a depth of 6 to 8 feet. Where erosion has been active, a part or all of the upper soil horizons are absent and in some cases the subsoil is exposed. Use and Management. — Surface drainage of Clinton silt loam is moderate to rapid, while underdrainage is moderate. The steeper slopes are subject to con- siderable erosion and should not be cultivated intensively. Many of them should remain in permanent pasture; tho if erosion has progressed to the stage where a stand of grass cannot be established, it may be necessary to plant trees to stop further erosion. This soil is often seriously injured by gully head-cutting. The 1941] Warren Counts 17 «u I Fig. 5. Good Use of a Sloping \k\-.\ of Clinton Silt Loam A thick growth of pasture is preventing erosion on this 10-percent slope. In Fig. 6 note In-,* of soil on a similar field planted to corn. control of this difficulty frequently requires the construction of check dams or diversion terraces in order to establish a sod or, in extreme cases, to get trees started. Clinton silt loam responds well to treatment tho it is not naturally a very productive soil. The first step in an effort to increase yields is to correct acidity by applying limestone as indicated by the test. Following this a rotation should Fig. 6. — Poor Use or a Sloping Area <>f Clinton Silt Loam The erosion on this field was caused by the growing of corn. An area of this kind should he in .urass (Fig. 5), or if the erosion has been too active, it may he necessary to plant trees. 18 Soil Report No. 70 [October, be adopted which includes the frequent growing of clover or alfalfa to be used as pasture or green manure. Barnyard manure gives excellent results on this soil but there is rarely enough available to make it possible to dispense with legume green-manure crops. If the clovers are used without barnyard manure, it frequently becomes necessary to use phosphate and sometimes potash fertilizers to compensate for the increased removal of these nutrients. Tama silt loam (36) Tama silt loam is a dark-colored soil that has developed under grass vege- tation on gently rolling to strongly rolling topography. It occurs thruout the county, generally as a belt around Clinton silt loam or along the drainage ways where Clinton does not occur. It is the second most extensive type in the county, occupying a total area of about 152 square miles. Where erosion has not been active, the surface is 5 to 7 inches thick and is a brown to light-brown silt loam medium high in organic matter and medium acid in reaction. The subsurface is a brownish-yellow silt loam 4 to 7 inches thick. The subsoil is a reddish- or brownish-yellow silty clay loam 12 to 18 inches thick that breaks into 1/4- to 1/2-inch rounded or nut-like aggregates. Beneath the sub- soil is permeable silt, which becomes highly calcareous at a depth of 5 to 7 feet. Where erosion has been active, a portion or all of the upper horizons may be absent. Since most of the slopes found on Tama silt loam were the result of erosion and not of constructional processes, they are generally short and are therefore not separated from Tama and shown as a steep phase on the accom- panying map. This wide range in topography and erodibility which Tama presents as it is mapped in Warren county is a variation that cannot readily be indicated on a map of the scale it was necessary to use in this county. Use and Management. — On the less rolling areas Tama silt loam is a good general farming soil when well handled. Surface drainage is rapid, while under- drainage is moderate and tile drainage is unnecessary. A test should be made for acidity, and limestone applied as indicated by the test. This soil is particularly well adapted to alfalfa, and this legume or one of the clovers should have a regular place in the rotation. The legumes may be so handled as to serve as a cover for the land during the winter and early spring months and thus help to decrease erosion as well as to maintain the supply of organic matter. Phos- phorus and potash may become deficient after legumes have been grown for a time. If the productivity level of this soil is not satisfactorily high after a good rotation has been established, tests should be made for available phosphorus and potassium, as a deficiency of one or both of these nutrients is indicated. Barnyard manure gives good results on Tama silt loam. The more rolling areas of Tama silt loam often require special attention. Fall plowing of these areas should be avoided, as a protective cover of vegetation is needed during the winter and early spring. Under a livestock system no better use can be made of the steeper slopes than to keep them in permanent pasture. Tf cultivation is necessary, unusual precautions should be taken to decrease erosion. Where corn is grown, the stalks should be rolled crossways to the slope. This simple practice is often very effective in helping to reduce erosion. Grass 1941] Warren Coun n I" waterways should be provided and contour farming practiced as far as possible. [f tin- slope is not too steep, terraces may be constructed to good advantage. It, however, erosion has removed so much of the loess as to bring the underlying leached glacial till near the surface, the advisability of terracing is questionable. Fig. 7. — Active Erosion on a Field of Tama Silt Loam Altho Tama silt loam is a good soil and the slope shown here is not particularly steep, the field is being seriously damaged by injudicious cropping. If corn is grown on areas such as this, it should be planted on the contour. Careful study of the yielding capacity of Tama silt loam on a number of Illi- nois farms indicates that under good management (as defined on page 27) open- pollinated corn may be expected to average about 48 bushels an acre; oats, 38 bushels; winter wheat, 24 bushels; and soybeans, 24 bushels. (See Table 2, page 12, where the yields to be expected from the various soil types of Warren county are indicated. ) Muscatine silt loam (41) Muscatine silt loam is a dark-colored soil that has developed under grass vegetation on undulating to gently rolling topography, where the slopes range between about 1 and 3i/£ percent. It occurs thruout the county in association with Tama silt loam and is the most extensive type in the county, covering a total area of 166 square miles. The surface, which varies from 7 to 10 inches in thickness, is a brown to dark-brown silt loam high in organic matter and medium acid in reaction. The subsurface is a yellowish-brown silt loam 7 to 9 inches thick. The subsoil is a yellowish-brown silty clay loam 10 to 16 inches thick, which breaks into 1/+- to i/2-inch faintly dark-gray coated subangular aggregates. Noncalcareous permeable silt, which becomes highly calcareous at a depth of 4 to 6 feet, lies beneath the subsoil. The entire profile absorbs water readily and is readily penetrated by plant roots. Use and Management.- Muscatine silt loam is a productive soil and needs 20 Soil Report No. 70 [October, Fig. 8. — Temporary Pasture on Muscatine Silt Loam Muscatine silt loam is a good soil and yields well under proper treatment. This pasture will probably be plowed for corn next year. only good farming and proper treatment to produce high crop yields. Natural drainage is moderate, and tho harmful erosion may occur on the more rolling portions of the type, it may be satisfactorily controlled by good farming methods. This soil is more durable than Tama silt loam and will stand more abuse without immediately disastrous results. The maintenance of a high productive level, however, cannot be expected without the application of limestone, phos- phate, and potash in amounts indicated by the tests and the use of a good rota- tion. If barnyard manure is available, it will help materially to maintain productivity and decrease the need for phosphate and potash. A stand of red clover often can be obtained on Muscatine in favorable seasons without limestone, but the stand is more certain and a better growth is usually obtained after a limestone application. For alfalfa and sweet clover an application of limestone is usually necessary. Fall plowing should be avoided on slopes greater than 2.5 or 3 percent, while the more nearly level portions should be tile-drained. Results from the Kewanee soil experiment field in Henry county, shown below, indicate the relative effective- Corn Oats Wheat Hay Treatment' 1 (24 crops) (24 crops) (21 crops) (22 crops) bu. bu. bu. tons None 60 53 28 1.6 Manure 75 65 33 2.2 Manure, lime 80 66 36 2.4 Manure, lime, rock phosphate . . 81 66 40 2.6 None 58 55 29 1.7 b Residues 64 54 31 1.4 b Residues, lime 73 58 34 1.6 b Residues, lime, rock phosphate 76 63 40 1 .9 b Residues, lime, rock phosphate, potash 77 63 40 1 .9 b ("Manure, 1 ton for each ton of crops grown; crop residues, stover, straw, legumes; limestone, 510 pounds an acre annually; rock phosphate, 340 pounds an acre annually; muriate of potash, 88 pounds an acre annually. h Average of 14 crops: 2 cuttings removed each year from the check plot and only one from the treated plots.) 1941] \\ u?ren County 21 ness of the fertilizer treatments thai have been used on this field, which is on Muscatine sill 1< iam. Under farm conditions, with good management, the following yields may be expected, as an average, from Muscatine silt loam, judging from studies carried mi 1>\ the Department oi Agronom) with the cooperation oi the Department oi Agricultural Economics: open pollinated corn, 54 bushels; oats, 46 bushels; winter wheat, 26 bushels; and soybeans, 2X bushels (Table 2. page 12). Grundy silt loam (43) Grundy sill loam is a dark-colored soil that has developed under a heavy prairie grass vegetation on gently undulating topography or on slopes between i _> and 1 percent. Il occupies about 41 square miles in Warren county. The surface horizon, which is 8 to 10 inches thick, is a dark-brown faintly granular silt loam to silty clay loam that is high in organic matter and nitrogen and slightly acid to neutral in reaction. The subsurface is a dark grayishd^rown silty clay loam 7 to 9 inches thick. The subsoil is a dark gray silty clay 10 to 16 inches thick, splotched and spotted with yellow, which breaks into 14 - to l/2-inch dark coated subangular aggregates. The loessial material immediately beneath the subsoil is usually noncalcareous for a few inches but almost always is highly calcareous at a depth of 3i/2 to 4 feet. This soil is easily penetrated by plant roots and absorbs and retains moisture readily. Use and Management. — Grundy silt loam, if well drained, is a very productive soil and, like Muscatine, needs only good farming and proper treatment to produce high crop yields. Surface drainage is moderately slow and erosion is negligible. Tile draw well, but it is sometimes difficult to provide a good outlet because of the topographic position of the type and distance to natural drainage ways. All crops common to the region do well on this soil. ( rrundy silt loam is a durable soil but good farming practices must be followed, including a good rotation, if its productivity level is to remain high. A satisfactory stand of red clover usually can be obtained without the use of limestone. In favorable years some alfalfa and even sweet clover will survive; but for best results, especially with sweet clover, a light application of limestone should be made. Results from the Aledo soil experiment held in Mercer county indicate the relative effectiveness of different fertilizers on this soil type. Corn Corn Oats Hay or Treatment* (28 crops) (16 crops) (27 crops) wheat h bit. bu. bu. (T) or bu. None 58 60 56 (2.0) Manure 74 74 64 (2.4) Manure, lime 76 78 66 (3.0) Manure, lime, nick phosphate 76 78 67 (3.0) None 57 61 56 28 Residues 64 67 58 30 Residues, lime 74 73 63 34 Residues, lime, rock phosphate 76 74 64 36 Residues, lime, rock phosphate, potash 78 77 67 37 r'See footnote ■> on opposite page. b Hay, 14 crops; wheat, 25 crops.) 'Subsequent to the printing of the Warren county soil map the name Grundy silt loam, as applied t" snil areas in Warren county, was changed t<> Sable silt loam. 22 Soil Report No. 70 [October, Monmouth silt loam (44) : Monmouth silt loam is a dark-colored soil that has developed under slough- grass vegetation on nearly level to undulating topography. It is not an extensive type in Warren county, occupying a total area of slightly less than 4 square miles. Tt occurs west of Monmouth as an irregularly shaped area. The surface, which is 7 to 10 inches in thickness, is a dark-brown faintly granular silt loam to silty clay loam very high in organic matter and, for the most part, neutral in reaction. The subsurface is a dark grayish-black clayey silt loam 6 to 8 inches thick. The subsoil is a brownish-gray yellow-spotted slightly plastic silty clay loam 10 to 16 inches thick. A zone or band of lime concretions frequently exists at a depth of 28 to 32 inches, and the silty material beneath the subsoil is generally calcareous at a depth of 3 feet. Plant roots easily penetrate the entire profile of this type and moisture is readily absorbed. Use and Management. — Monmouth silt loam is similar to Grundy silt loam except that it is calcareous (high in lime) immediately beneath the subsoil and therefore probably also higher in lime in the upper portions of the profile than Grundy. The treatment and management suggestions for Grundy silt loam (page 21) apply to Monmouth also, and the yields to be expected are probably comparable. Denny silt loam (45) Denny silt loam is a medium-dark soil that has developed under scanty grass and weed vegetation on nearly level or slightly depressional topography. It is a very minor type in Warren county, occupying a total area of only about 1/4 square mile. Altho the total area of Denny is small, it is an important soil since it is relatively poor yet occurs in association with two very productive soils, Musca- tine silt loam and Grundy silt loam. It occurs generally as small isolated or dis- connected spots which are often smaller than an acre in size. For this reason many individual spots are not shown on the soil map. Where several spots occur close together, they are shown as one area. The surface is a grayish-brown silt loam 7 to 9 inches thick, medium in organic matter and acid in reaction. The subsurface is a dark-gray or brownish- gray silt loam 5 to 8 inches thick. The subsoil is a gray plastic silty clay 14 to 22 inches thick which in the upper portion breaks into i/j.- to 34 -inch dark- coated subangular aggregates. The aggregates become larger and more irregular in appearance below 2 feet and tend to disappear at about 3 feet. Beneath the subsoil the material is a leached, or noncalcareous, friable silt which becomes calcareous at a depth of 6 to 8 feet. Use and Management. — Plant roots do not easily penetrate the subsoil of Denny silt loam, and water is not readily absorbed. Tho many of these spots occur at the heads of small draws, they are frequently wet and difficult to farm. Also, since the plastic subsoil tends to limit the effectiveness of tile, the response of crops to soil treatment is often disappointing. Sweet clover will grow after soil acidity has been corrected ; and frequent applications of manure will help to 'After the printing of the Warren county soil map, the name Monmouth was changed to Hartsburg. 1941] Warren County 23 raise the productivity level. Special treatment of Denny silt loam is often not practicable because this soil occurs in small areas in association with soils not requiring special treatment. When limestone is applied to a field in which spots of Denny occur, a double application can be made to these spots without much extra Fig. { >. — An Area of Denny Silt Loam in a Field of Muscatine Silt Loam The light-colored soil in the background is Denny silt loam, a relatively poor claypan -oil. It usually occurs, as it - - / J C r h C U 2 _ < _ - - — w s guu"5 •c — - - - -" J O d. U. C E w -. «j - %. ■} a DC *J : — — .22 w w w w - ' "IL U w w ■ a ■ 3 >.— -5 "3 — - - - - ; w V J g -J ~ ■ § - i *s » « i: - - ~ 3 3 ^7? ~7 YYY YY 2>Scn2 SZ2 w b. u j. u > - te 3 ™j : «! 5 O .O « - -r-o-cx — -r s.hi.t g-a-a •C-3 _* it 9 o,S " ^ 3 c c 0053; - " ' - r -- J J J J ."_" — — - — > J J - w w — . 6 , >.T3 •_ '. U 01 ■- •_ CO—'. B B E B c C C v- _._._. : :n : 5 0.3. 5 0, : : E - _:_:_:_ *Z.Y.--Y U! /■:_:_:/' -YY E "m 12 £ - E £ C 3 3 3 3 3 f B ssi"i mmI! sii m^iIm"*. *mw OSOmS _:__x-_ — -w ***• b~ _. £^~f = ^~~ u >. 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E -~ - -3 - 3.w II S&- ■•§:! > u. -w O u ~ c. £ . <- 3 - 3-.1 _x » - |_ 3 c - " *>e b "" * S E •- C = -ww - - '- E i • u ■a Z Ji > S - ii - I ~ ~ r 2 '- =■ -.3— 3 S E Si ■a B U '-■> £ o, - * - ~ ~ ' bo -- _ 1 . . 3 — "- 'S — -^ *- - ' ^> £- w C - ?KS2g(J . ■ 3 - >. : ~ 4. = = i ^- 3 C 3w- = ■7 •- ~ 3 "- O 3 — /: w : =— .' ~ ° £- s I Si i — x 1-— r- -3 - '- - w — - / - _ - 3 - r _ _ >"" : i 3 > 3 E .r-3'-- =-i|'7 e ■/ G « ** a -9 >- a '- ^ ^* - ™ - "- >■ — ;53 3w;-^w b ftg^SoJidi - ■•* O w> o -. r- w C 7. ^ — /. -" 3«-^«=^ ALPHABETICAL INDEX TO SOIL TYPES PAGE Alexis silt loam, terrace 26 Berwick silt loam 15 Camden silt loam, terrace 26 Clinton silt loam 16 Denny silt loam 22 Grundy clay loam 23 Grundy silt loam 21 Harpster clay loam 24 Hersman clay loam, terrace 27 Hersman silt loam, terrace 27 Hickory gravelly loam, eroded 14 Huntsville loam, bottom 25 Kern silt loam, terrace 23 Littleton silt loam, terrace 26 Monmouth silt loam 22 Muscatine silt loam 19 Swan clay loam, bottom 26 Tama silt loam 18 SOIL REPORTS PUBLISHED 1 Clay, 1911 2 Moultrie, 1911 3 Hardin, 1912 4 Sangamon, 1912 5 LaSalle, 1913 6 Knox, 1913 7 McDonough, 1913 8 Bond, 1913 9 Lake, 1915 10 McLean, 1915 11 Pike, 1915 12 Winnebago, 1916 13 Kankakee, 1916 14 Tazewell, 1916 15 Edgar, 1917 16 Du Page, 1917 17 Kane, 1917 18 Champaign, 1918 19 Peoria, 1921 20 Bureau, 1921 21 McHenry, 1921 22 Iroquois, 1922 23 DeKalb, 1922 24 Adams, 1922 *25 Livingston, 1923 26 Grundy, 1924 27 Hancock, 1924 28 Mason, 1924 29 Mercer, 1925 30 Johnson, 1925 31 Rock Island, 1925 32 Randolph, 1925 33 Saline, 1926 34 Marion, 1926 35 Will, 1926 36 Woodford, 1927 37 Lee, 1927 38 Ogle, 1927 39 Logan, 1927 40 Whiteside, 1928 41 Henry, 1928 42 Morgan, 1928 43 Douglas, 1929 44 Coles, 1929 45 Macon, 1929 46 Edwards, 1930 47 Piatt, 1930 48 Effingham, 1931 49 Wayne, 1931 50 Macoupin, 1931 51 Fulton, 1931 52 Fayette, 1932 53 Calhoun, 1932 54 Ford, 1933 55 Jackson, 1933 56 Schuyler, 1934 57 Clinton, 1936 58 Washington, 1937 59 Marshall, 1937 60 Putnam, 1937 61 Wabash, 1937 62 Vermilion, 1938 63 St. Clair, 1938 64 Stark, 1939 65 Boone, 1939 66 Shelby, 1939 67 DeWitt, 1940 68 Jasper, 1940 69 Cumberland, 1940 70 Warren, 1941 ('Withdrawn from general circulation) Requests from libraries and other public agencies desiring to com- plete their files of these reports will be given special consideration. 4000—10-41—21560 UNIVERSITY OF ILLINOIS-URBANA Q630.7IL6SR CBD = ILLINOIS AGRiCULTURALExSvENT STATION 3 0112 019543971