THE UNIVERSITY OF ILLINOIS LIBRARY REVENTION 517 FIG. 4. ADVANCED STAGE OF EROSION IN ADAMS COUNTY, DUE TO A SUBSTRATUM OF INCOHERENT SAND RAINFALL IN ILLINOIS Illinois lies in the belt of prevailing westerly winds. Much of the rainfall comes in moderate or gentle rains, during which a large proportion of the water enters the soil, but in the summer particu- larly there are very heavy rains, and as the soil is unable to absorb so much water in such a short time, much of it runs off the sloping land. From Table 2, which shows the average rainfall by seasons in the various sections of the state, it will be seen that the greatest rainfall is in the spring and summer months, when the soil is in the best condition to absorb water ; but in spite of this fact there is an enor- mous run-off from the rolling land of the state. TABLE 2. AVERAGE SEASONAL RAINFALL IN ILLINOIS District Winter Spring Summer Autumn Extreme northern 1 . . . '. ^Central-northern 2 .... inches 5.44 5-. 80 6.82 8.80 10.66 percent 16.0 16.8 18.0 21.2 24.8 inches 9.34 9.61 10.43 11.75 12.38 percent 27.4 27.9 27.9 28.3 28.5 inches 11.22 10.75 11.04 11.75 10.70 percent 33.0 31.6 30.7 28.3 24.7 inches 7.99 8.11 8.60 9.18 9.54 percent 23.6 23.7 23.4 22.2 22.0 Central Central-southern^ . Extreme southern 1 4866 to 1915. =1850 to 1915. 518 BULLETIN No. 207 [April, RUN-OFF The extent to which washing occurs depends upon the amount of surface run-off. The amount of run-off and the effect which it has depends to a large extent upon the character of the soil and subsoil, the length and steepness of the slope, the tillage practiced, and the vegetation growing upon it. Because of these many varying condi- tions, it is difficult to compute the amount of run-off. Considerable work has been done, however, which may form the basis for a fair estimate. Table 3 gives the results of the work of Mr. F. H. Newell, formerly Chief Hydrographer of the U. S. Geological Survey. TABLE 3. PERCENTAGE OF RUN-OFF FROM THE SAVANNAH, CONNECTICUT, AND POTOMAC RIVER BASINS Basin Time Percentage of rainfall carried off in drainage Savannah river ... 1884 to 1891 48.9 Connecticut river : 13 years 56.5 Potomac river 1886 to 1891 53.0 It has been estimated that for broad valleys and gentle slopes in open country, a mean annual rainfall of 50 inches gives an annual run-off of about 25 inches, or 50 percent of the total rainfall. Where the rainfall is 40 inches, the run-off is about 15 inches, or 37.5 percent ; and where the rainfall is 30 inches, the run-off is about 8 inches, or 26.6 percent. Greenleaf estimates the average run-off for the Illinois river basin at about 24 percent of the total rainfall of the catchment area. Leverett estimates the run-off for the entire state of Illinois at about 21 percent of the rainfall. The work of the Illinois State Geological Survey shows that the run-off for the Spoon river basin is 21.5 percent of the total rainfall ; for the Embarrass river basin, 25 percent ; and for the Kaskaskia, 37.9 percent. Table 4 will be of interest as showing the run-off in the Kaskaskia river basin for the years 1907 to 1909. The very high TABLE 4. RAINFALL AND RUN-OFF IN THE KASKASKIA RIVER BASIN, 1907-1909 1907 1 gorges started. One of these is now 30 rods long, from 50 to 70 feet wide, and from 23 to 35 feet deep. A concrete dam has been placed near its head to stop further encroachment (Fig. 26). The other gorge has extended about 40 rods and is from 30 to 50 feet wide and from 20 to 30 feet deep. Near the end of this gorge the tile again branches, and two gorges are starting; these have advanced 4 to 6 rods along the tiles. At a depth of 4 to 8 feet there is a stratum of fine, incoherent sand, which washes out very readily, allowing the unsupported surface to cave in (Fig. 5). 522 BULLETIN No. 207 [April, EFFECTS OF EROSION Loss OF ORGANIC MATTER, NITROGEN, AND PHOSPHORUS Nothing will completely ruin land more quickly than erosion, especially gullying. A great many fields have already been abandoned from this cause. A single season or even a single rain may produce gullies that cannot be crossed with ordinary farm implements. Unless erosion is practically stopped, the land soon becomes almost worthless (see Fig. 9). While sheet washing may not ruin land so quickly and so com- pletely as gullying, yet much more damage is done by it because it occurs over a much greater area. This type of erosion takes place to a damaging extent on the undulating land, and to a greater extent upon the more rolling and hilly lands. Prairie soils are not subject to so much erosion as timber soils, since their higher organic-matter content protects them to a considerable degree. The first effect of erosion is to remove the surface soil. Since this commonly contains a larger supply of organic matter, nitrogen, and phosphorus than any other stratum, its removal naturally lowers the plant-food content in the type of soil most subject to erosion, and increases it in the one receiving the wash. Hilly timber land is naturally deficient in organic matter, and after it has been cleared and cultivated the run-off soon removes a very large part of the surface soil and along with it the organic matter and the two most important elements of plant food, nitrogen and phosphorus. It should be noted, however, that soils naturally subject to erosion, such as yellow silt loam, may contain as much or even FIG. 7. A WELL-PROTECTED TILE OUTLET. 1918} WASHING OF SOILS AND METHODS OF PREVENTION 523 FIG. 8. WATERFALL EROSION ON PASTURE LAND IN OGLE COUNTY FIG. 9. EFFECTS OF SHEET WASHING, PIKE COUNTY more phosphorus in the subsoil or the subsurface than in the surface, even when equal weights are considered. Table 5 shows the amount of organic matter, nitrogen, and phos- phorus in the surface stratum of each of the two representative timber soils in the state and 'of the bottom land receiving their wash. Yel- low-gray silt loam has not suffered much from washing, but yellow silt loam is generally badly eroded. The abandoned land is usually of this latter type. The bottom land receives much sediment from the yellow-gray silt loam areas and some from other less rolling types, but it receives perhaps even more from the yellow silt loam. 524 BULLETIN NO. 207 [April, TABLE 5. ORGANIC MATTER, NITROGEN, AND PHOSPHORUS IN THE SURFACE M OP REPRESENTATIVE TIMBER SOILS AND THE BOTTOM LAND RECEIVING THEIR WASH 2 million pounds of surface soil per acre (0-6% inches) County Yellow-gray silt loam (undulating) Yellow silt loam (hilly) Bottom land (small streams) OM N P OM N P OM N P Bond tons 22.8 16.9 13.4 26.9 22.4 27.8 28.1 26.7 29.0 24.3 22.6 22.6 20.1 19.6 /6s. 2530 1 650 1 520 2710 2440 2720 2527 2620 2940 2310 2 120 2300 2020 2 200 /6s. 470 550 870 810 860 750 1033 880 1 050 680 780 1 010 850 870 tons 19.1 14.7 11.0 20.7 21.9 18.1 20.7 18.4 15.3 16.6 14.8 8.8 15.3 24.8 /6s. 2068 1 540 1 250 2040 2330 1 880 2093 2 140 1 650 1 580 1 590 920 1 710 2480 /6s. 696 510 840 720 820 720 773 830 750 480 730 820 840 910 tons 25.4 25.1 11.6 97.1 52.4 77.1 36.7 40.5 62.8 28.6 34.8 44.0 35.9 63.1 /6s. 2605 2805 1 195 9020 4910 8 190 4440 4580 6300 3390 3230 4450 3820 6770 /6s. 1 370 1 050 615 1 560 1 790 1 490 1 260 1 740 1 940 940 1 150 1 630 1 255 1860 Clay. . Hardin . . . Kankakee Knox Lake. ... LaSalle McDonough . . . McLean Moultrie Pike Sangamon .... Tazewell Winnebago . . . Average 23.1 2330 819 17.1 1 805 746 45.3; 4693 1403 This table shows that in the surface 6% inches yellow-gray silt loam contains an average of 23.1 tons of organic matter per acre; yellow silt loam, 17.1 tons ; and the bottom land, 45.3 tons. The nitro- gen and phosphorus content in the surface soil of these three types varies in this same order, the types containing respectively 2,330, 1,805, and 4,693 pounds of nitrogen; and 819, 746, and 1,403 pounds of phosphorus per acre. A nitrogen content of only 1,805 pounds per TABLE 6. ORGANIC MATTER, NITROGEN, AND PHOSPHORUS IN THE STRATUM OF REPRESENTATIVE TIMBER SOILS 4 million pounds of subsurface soil per acre (6% - 20 inches) County Yellow-gray silt loam (undulating) Yellow silt loam (hilly) OM N P OM N P Bond tons 18.2 11.8 11.7 20.7 14.5 22.6 20.7 15.0 19.3 15.1 24.5 14.5 12.9 14 /6s. 2600 1 520 1 500 2710 2210 2630 2280 2 150 2710 2040 2 140 2 150 2090 2220 Ibs. 1340 860 1820 1280 1420 1 300 1 907 1 420 1 490 1 100 1 370 1 760 1 580 1 820 tons 14.7 13.6 8.2 17.4 14.7 20.7 15.5 11.5 13.1 14.8 12.6 11.5 11.7 25.9 /6s. 2 120 1 830 1390 2 160 1 870 2720 2280 1960 2020 1 720 1 600 1540 1 650 2980 /6s. 1 270 790 1 930 1 400 1 610 1 620 1 387 1 700 1 540 1 200 1 560 1880 1 670 2 180 Clay Hardin Kankakee Knox Lake LaSalle McDonough McLean Moultrie Pike Sangamon Tazewell Winnebago Average 16.8 2210 1462 14.7 1 990 1553 Idl8\ WASHING OP SOILS AND METHODS OP PREVENTION 525 acre is not sufficient to produce profitable crops. If that amount is not a sufficient reserve from which to grow fair and profitable crops, what can be expected from a soil whose nitrogen content has been re- duced by washing to one-half the above amount, a condition which is produced when the surface soil is removed by erosion (see Table 6). In comparing the figures in Table 5 and Table 6, it will be well to remember that the subsurface stratum is twice the thickness of the surface layer ; so that in the subsurface of yellow silt loam, for example, there are but 995 pounds of nitrogen in a stratum of the same thick- ness as the surface stratum. CHANGES IN THE PHYSICAL CHARACTER OF THE SOIL Two distinct changes in the physical character of the soil are produced by erosion: first, a change in color; and second, a change in the physical composition, or texture. The surface soil of the rolling timber types has a brownish yellow color, owing to the mixture of organic matter and iron oxid. When erosion takes place, the yellow or. reddish yellow subsurface or subsoil is exposed. The effect is to slightly reduce the temperature of the soil, since yellow soils do not absorb heat so readily as the darker colored soils. The most important change in physical character is that of tex- ture. The surface soil is usually a mealy, friable, silt loam, easy to work. The subsoil is often a somewhat tenacious, yellow clayey silt or silty clay, and when this is exposed by erosion it forms a soil that is very difficult to plow and still more difficult to reduce to a condition of good tilth for a seed bed. The physical condition of this subsoil renders it a slow absorbent of water, so that the run-off is actually increased by erosion. 526 BULLETIN No. 207 '[April, METHODS OF REDUCING EROSION It would commonly be taken for granted that the thing of first importance in reducing erosion is the preventing of the formation of gullies in cultivated fields, but this is not the case. The beginning of the trouble is usually due to sheet washing, and as a rule gullying occurs in the later stages of the general process of land ruin. If we can prevent sheet washing, we shall very largely lessen gullying in cultivated fields. REDUCING SHEET WASHING Five general methods are employed for the prevention of sheet washing: (1) growing cover crops, in order to decrease the move- ment of water and soil; (2) increasing the organic-matter content, in order to bind the soil particles together; (3) using methods of tillage which will check the velocity of- the run-off and cause greater absorp- tion; (4) tiling in order to increase the porosity of the soil and con- duct the water thru safe channels; and (5) constructing terraces and embankments which encourage the absorption of the rainfall or so modify the slope of the land as to conduct the surplus water off at a grade that will cause little or no washing. 1. Cover Crops. In the management of rolling land, a rota- tion should be adopted that will keep the land in pasture and meadow during a large part of the time, or that will at least keep a covering of vegetation on the soil as much of the time as possible. Before these rolling and hilly lands were brought under cultivation, they were largely covered with vegetation of some form. The leaves of trees and fallen branches, together with the smaller plants, formed a cov- ering that did much to prevent the soil from washing. The rainfall was held by the layer of leaves and mold, and the water was allowed to pass off slowly to the streams. But as soon as the protecting forest was removed, the water ran off in a flood almost as soon as it fell. The upland timber soils of the state were usually in poor physical condition when first put under cultivation, or became so after a few years of cropping, and consequently percolation is comparatively slow. If a cultivated crop is grown, such as corn, a cover crop should be put in just before or after the last cultivation, to protect the soil from washing during the fall, winter, and spring. Rye is one of the best cover crops for this purpose because it lives thru the winter and makes a fair growth of top and an abundance of fine, fibrous roots that hold the soil particles in place. It may be left for green manure or pasture in the spring. A mixture of lye and sweet clover may prove better than rye alone. WASHING OF SOILS AND METHODS OF PREVENTION 527 Cowpeas may be used as a cover crop with fair success, especially in the southern part of the state, but they do not have the binding power of rye and are killed by frost. The clovers, either sweet, red, or alsike, may make sufficient growth during favorable seasons to protect the soil during the winter and spring, but they are not so sure as rye unless the soil is treated or especially adapted to them. Besides, much of this rolling land in southern Illinois is sour and must be sweetened with ground limestone before clover will do its best. As already stated, thesa legumes, aside from their value as cover crops, are also very beneficial to the soil for the nitrogen they supply. The clover may be left and turned under as a green manure in time to plant another crop, such as corn, or it may be harvested or pastured, or, what is better still from the standpoint of soil improvement, the entire crop may be turned under. It must always be borne in mind, however, that a large growth of clover removes a very large amount of moisture from the soil, and when turned under as green manure in dry seasons it may leave the soil so dry that the succeeding crop will suffer. In general, any crop may be grown as a cover crop that will furnish sufficient material both of top and roots to hold the soil in place. The seeding of rye and timothy in the fall, with red clover and alsike in the spring, followed by pasturing, is one of the very best methods of treatment. Crab grass in corn may make a good cover also. Much of the rolling and hilly land of the state should be kept in permanent blue-grass pasture (see Fig. 10). If sweet, alsike, or white clover can be grown along with the blue grass, much better results will be obtained. The binding power of blue-grass roots is very great, and gullying is almost entirely prevented except when waterfalls start FIG. 10. A GOOD WAY TO MANAGE HILLY LAND is TO KEEP IT IN PERMANENT BLUE-GRASS PASTURE 528 BULLETIN No. 207 [April, (see Fig. 8) and gullies advance by head-water erosion. If blue grass only is grown, the soil becomes very compact, so that comparatively little rainfall will be absorbed. At most, the amount absorbed is small. Clovers, and particularly sweet clover, with its deep roots, loosen the soil, keeping it in good condition. Besides, the clovers furnish nitrogen for the grass. 2. Increasing the Organic-Matter Content. In the management of the soils of rolling land, it is important to. add organic matter, not only because of the effect it has in preventing washing and in pro- ducing good tilth, but also because it increases the moisture capacity, conserves the moisture, aids ventilation, and furnishes a supply of nitrogen for the plant (see Fig. 11). One of the effects of organic FIG. 11. WHEAT AFTER CLOVER Farm of A. P. Schroeder, Pulaski county. Showing possibilities of production on rolling land. matter on a soil is to keep it loose and porous by forming granules. In this condition the soil will readily absorb water and the run-off will be greatly reduced. A granular soil will not erode to any considerable extent, not only because there is less run-off, but also because the gran- ules are too large to be moved readily by water. The organic matter also prevents to a large extent the formation of impervious crusts by beating rains. The amount of organic matter naturally present in the soil varies quite widely with the type of soil. In general, the upland timber soils of the state have much less organic matter than the prairie types. The chief reason for this is the fact that in the prairie soils the roots of the grasses which once covered them, being protected by the moist 1H18] WASHING OF SOILS AND METHODS OP PREVENTION 529 soil, underwent only partial decay, while in the forest the leaves of the trees falling upon the surface of the ground were exposed to com- plete decay or to destruction by forest fires. Table 7 gives the amount of organic matter in the surface and subsurface strata of the principal types of timber and prairie soils of the state at the present time, calculated from the total amount of organic carbon found. TABLE 7. AMOUNT OP ORGANIC MATTER IN THE PRINCIPAL TIMBER AND PRAIRIE SOILS OF ILLINOIS (Surface 2 million pounds, subsurface 4 million pounds per acre) Area and county ^Tim bcr&~Jjf _^jTPr iirie^*2'l a (M ^p* *.'[ U|J| flllll o f d i, e rauriUiCC sunacc Unglaciated : Hardin tons 12.6 tons 10 4 tons tons Johnson 17.1 13.1 Average 14.8 11.8 Lower Illinoisan: Bond 19.9 12.4 26.0 26.6 Clay ' 15.4 10.9 22.9 29.8 Average 17.6 11.6 24.5 28.2 Middle Illinoisan: Sangamon 15.7 16.8 44.0 52.2 Upper Illinoisan ' Knox 22.3 15.5 58.1 66 McDonough 27.2 11.7 50.0 59.2 Pike 18.9 17.9 31.5 46.2 Average 22.8 . 15.0 46.5 57.1 Early Wisconsin: LaSalle 24.4 18.0 52.0 47.7 McLean 22 2 17.1 50.7 54.6 Moultrie . 19 3 14.8 50.9 48.4 Tazewell 17.5 12.1 57.9 62.7 Average 20.8 15.5 52.9 53.4 Late Wisconsin : DuPage . . 22 4 18.7 65.3 47.6 Lake 19.8 17.0 77.5 78.5 Average 21.1 17.8 71.4 63.1 To show the value of legumes on soils subject to erosion, the results obtained in some pot-culture experiments at the University of Illinois are presented. A soil taken from the washed hill land in Pulaski county was placed in pots, and different elements of plant food were added to all except one pot, which served as a check. Fig. 12 shows the difference in growth due to the different methods of treat- ment. Wheat was grown the first four years, after which wheat and oats were grown in alternate years. In Pots A2, All, and A12, after 530 BULLETIN No. 207 [April, FIG. 12. EFFECT OF NITROGEN AS SUPPLIED BY LEGUMES OB IN COMMERCIAL FORM the wheat and oats had been harvested, cowpeas were seeded and turned under for the crop following. The yields obtained under the various treatments are shown in Table 8. It must be remembered that these yields were obtained in the greenhouse under conditions much more 'favorable than are ordinarily found in the field. It is interesting to note that the average yields without treatment were 9.0 bushels of wheat and 41.5 bushels of oats TABLE 8. CROP YIELDS IN POT-CULTURE EXPERIMENT WITH YELLOW SILT LOAM OP WORN HILL LAND AND NITROGEN-FIXING GREEN-MANURE CROPS (Grams per pot) Pot No. Al A2 All A12 A3 A6 A9 A8 Treatment None LLe ' LLeP LLe PK LN LNP LNPK LPK I90;i Wheat 5.0 10.0 14.0 10.0 17.0 2(3.0 31.0 3.0 1904 Wheat 4.0 17.0 19.0 20.0 14.0 20.0 34.0 3.0 1905 Wheat 4.0 26.0 20.0 21.0 15.0 18.0 21.0 5.0 1906 Wheat 4.0 19.0 18.0 19.0 9.0 18.0 20.0 3.0 1907 Oats 6.0 37.0 27.0 30.0 28.0 30.0 26.0 7.0 1908 Wheat 4.0 16.3 10.2 16.0 13.0 3.6 7.7 3.5 1909 Oats 10.2 27.2 24.2 34.6 27.4 66.8 51.8 10.2 1910 Wheat 2.1 15.3 20.0 32.8 21.0 37.4 31.4 4.1 1911 Oats 6.4 11.1 20.6 24.2 32.8 38.4 39.5 6.1 1912 Wheat 0.1 19. a 18.4 25.9 25.9 25.9 23.8 4.1 1913 Oats 6.2 26.2 22.2 24.5 27.6 30.8 21.6 7.0 1914 Wheat 0.3 19.9 15.6 21.6 12.2 13.1 9.7 5.2 1915 Oats 12.7 24.0 25.1 22.9 21.3 16.6 17.3 15.5 1916 Wheat 7.0 14.2 10.2 17.5 13.7 7.2 11.4 4.3 Average of 9 years Wheat 3.4 17.4 16.2 21.1 15.6 18.8 21.1 3.9 Average of 5 years Oats 8.3 25.1 23.8 27.2 27.4 36.5 31.2 9.2 Yield Calculated to Acre Basis (Bushels) Wheat 9 46 4 43 2 56 3 41 6 50 1 56 3 10 4 Oats 41.5 125.5 191.1 136.2 137.1 182.6 156.2 45.8 NOTE. L=limestone; L3=legume; P= phosphorus; K potassium (kalium) N=nitrogen. 1918} WASHING OF SOILS AND METHODS OF PREVENTION 531 .per acre, and with lime, phosphorus, and potassium added they were 10.4 and 45.8 bushels respectively ; that with lime and legumes added, the yields were 46.4 bushels of wheat and 125.5 of oats; while with lime and nitrogen (dried blood), they were 41.6 bushels of wheat and 137.1 bushels- of oats ; and that the average of all pots receiving nitro- gen and other plant food was 49.0 bushels of wheat and 154.8 bushels of oats. The experiment certainly demonstrates the fact that soils sub- ject to erosion need nitrogen; and one of the great problems of the farmer on this kind of land is not only to maintain but to increase the supply of nitrogen in the soil. The most practical way of doing this on an extensive scale is to add organic matter by turning under legumes and manure, ground limestone being used as needed to cor- rect acidity (see Bulletin 115 of this station). To increase the organic matter in soils, it is necessary to utilize all the vegetable matter produced. Farm manure should be turned back into the soil as soon as possible. Too often it is left piled up against the barn, where it rots the boards and where much of the most valuable part of it leaches away. Weeds, stubble, and corn stalks should be plowed under instead of being burned, as is so frequently done. Crops of rye, or preferably legumes, should be grown and turned under ; they will not only increase the organic-matter content, but at the same time augment the scanty supply of nitrogen in these FIG. 13. COWPEAS ON SERIES C, UNIVERSITY OF ILLINOIS EXPERIMENT FIELD AT VIENNA When turned, under, the cowpeas materially increase the nitrogen and organic- matter content of the soil. 532 BULLETIN No. 207 [April, soils (see Fig. 13). A crop of cowpeas or clover is not wasted if plowed under; the increased yield of the succeeding crops may more than pay for it. The turning under of cover crops will help to increase the supply of organic matter, but this is too slow a process on land that is washing badly; one or two entire crops in a four-year rotation should be plowed under until the supply is materially increased. Sweet clover is one of the best crops to grow for the improvement of eroded land (see Fig. 14) for the following reasons: (1) a surer and better catch may be obtained with it than with red clover; (2) its very deep-rooting nature and large growth makes it most valuable for soil renovation; (3) it will grow on almost any kind of soil, whether badly eroded, good, or stony, the only necessary conditions being the presence of limestone and the proper bacteria; (4) it will furnish a large amount of excellent feed in the form of pasture or hay; (5) it possesses a feeding value as high as that of red clover; (6) it is one of our best honey-producing plants ; (7) it will likely be a money crop because of the amount of seed it produces and the price the seed brings. All forms of organic matter are about equally important to the soil from a physical standpoint, yet legumes are much more valuable than other plants because of the large amount of nitrogen which they contain. A ton of corn stalks contains 16 pounds of nitrogen; oat straw, 12 pounds; wheat straw, 10 pounds; clover, 40 pounds; cow- peas, 43 pounds ; and sweet clover, about 40 pounds. A 50-bushel crop FIG. 14. SWEET CLOVER ON THE VIENNA EXPERIMENT FIELD Growth during the first season (seeded in March), WASHING OF SOILS AND METHODS on 1 PREVENTION 533 of corn requires for its production 75 pounds of nitrogen. To provide this nitrogen, about 1,500 pounds of average soil humus must be de- composed and lost to the soil. If the average amount of humus in the surface seven inches is 2 percent, or 20 tons per acre, it would require only twenty-seven 50-bushcl crops of corn to completely exhaust the supply of soil humus ; from which it may be seen that even if a soil has a good store of organic matter to begin with, it does not require a great many years of cropping to reduce the supply below what it should be. This rapid depletion of organic matter is hastened mate- rially by washing, and it soon reduces the soil to a condition of unpro- ductiveness. The more a soil is ' ' run down, ' ' the more difficult it is to grow clovers or other soil-renovating crops. (See Bulletin 115.) 3. Tillage. Probably nothing that can be done to rolling land damages it more seriously than faulty methods of tillage. This is a fact which the farmers of Illinois have not yet learned. The direction of plowing, planting, and cultivation is usually determined by~~cbn- venience alone, regardless of consequences. Plowing is more frequently done up and down the hill than any other way, and the making of dead furrows in this direction affords the best possible beginning for a gully. The work of one season's run-off may be sufficient to produce a gully that the next season's tillage operations will not fill, and the slight draw soon increases and becomes a source of constant trouble. On land subject to serious washing, plowing should always be done along contour lines, or across slopes, the slopes being kept as uniform as possible in order to prevent any accumulation of water in draws. When done in this way, the water in running across the furrows meets with more obstructions and greater resistance than in running with the furrows, as in up-and-down-hill plowing, and more absorption takes place. While the direction of plowing is important, the dep_th is of equal importance, for a deep layer of loose soil will absorb a heavy rainfall without run-off. The soil should be plowed to a depth of six to eight inches. Planting also should be done across the slope. The authors have observed ditches six inches or more in depth in the track of a planter a week after seeding, where the rows had been run up and down hill. All the corn had been washed out by the water which had accumulated in and followed the planter track. If the corn rows had been run on the contour of the slope, this could not have taken place. Cultivating up and down the hill allows the accumulation of water between rows, and this results in the formation of a large number of small gullies, in the making of which much soil material is removed (see Fig. 15 and 16) . In contour planting, each row retards the move- ment of water down the slope, thus permitting greater absorption. 534 BULLETIN No. 207 [April, FIG. 15. GULLIES PRODUCED IN A SINGLE SEASON (1916) The corn was cultivated up and down the slope. FIG. 16. ADVANCED STAGE OF GULLYING STARTED IN THE SAME WAY AS IN FIG, 15 1918] WASHING OF SOILS AND METHODS OF PREVENTION 535 Such crops as wheat and cowpeas should also be drilled along contour lines. 4. Tiling. The placing of lines of tile on slopes is a very effect- ive way of reducing erosion. The soil is made more porous, and conse- quently a large part of the water is removed thru the tile, instead of collecting and running off in draws. Slopes frequently have places where the seepage water comes to the surface, producing cold, wet spots. This condition may be entirely remedied by tiling. The expense involved is the most serious objection to the use of tile in preventing erosion. 5. Terraces. In the southern states it is a common practice to terrace cultivated slopes. The type of terrace depends on the steep- ness of the slope and the character of the surface soil and the subsoil. The "level bench," "guide row," and "mangum" are all in use. The level bench is used on the steeper slopes. Contours are es- tablished at a difference in elevation of three to five feet. Each terrace is then plowed downward with a hillside plow. In a few years enough soil is moved to make a fairly level bench. Each bench must be cul- tivated separately, and cuts or tracks across the edge of the bench must be avoided in order to prevent destruction by erosion. The guide row is developed by throwing several furrows together on contour lines. Crops are seeded along or parallel to these rows. In time, with the use of the hillside plow, these may easily be devel- oped into the level bench. In both of these types there is a strip of uncultivated land on the edge of the terrace. This should have a good sod upon it to hold the soil. This uncultivated strip is undesir- able, as it is a waste of land and considerable time is required to keep down the weeds, which aside from their encroachment upon the crop, serve also as a home for mice and moles and as a breeding place for injurious insects. The mangum terrace (Fig. 17) differs from the terraces just described in that it has some fall from the back to the front of the terrace as well as a grade of about one inch in ten feet from one end of the terrace to the other. The width of the terrace depends on the general slope of the area. In order to build up an embankment, sev- eral furrows are thrown together along a line of proper fall established by means of a level, and, to increase its height, soil is drawn to it from the upper side, making a low, broad dyke. When the field is plowed again, the ridge may be raised by back-furrowing along the grade line. This process may be continued from year to year until the desired height is reached. The steeper slopes require a higher embankment. About six feet of fall is allowed between embankments, so that the terraces on very steep land will be 40 to 80 feet wide, and on more gently sloping land 100 to 150 feet wide. By this method the run-off 536 BULLETIN No. 207 [April, FIG. 17. MANGUM TERRACE (Courtesy, Bureau of Plant Industry, U. S. D. A.) is conducted slowly around the slope in a broad-bottomed ditch to a natural outlet, without much washing. It is essential that the water be given no opportunity to get over the embankment, as it would cut a gully across it, drain the ditch, and ruin this and possibly several embankments below. Crops may be planted in any direction, with little reference to the terraces, but it is most desirable to have the rows run obliquely across them, so that there will be a slight fall along the rows toward the ditch. This should aid the soil in absorbing more of the rainfall. The mangum terrace has a distinct advantage over the other types in that there is no waste land. This form of terrace has attracted much attention, and of the various types, is the one best adapted to extensive farming. If cover crops and organic matter are used to the best advantage, and if deep contour plowing and contour seeding are practiced, there will not be much need for any terracing in this state. However, the mangum terrace, properly constructed, may in some places be used to advantage. FILLING AND PREVENTING GULLIES The owner of rolling or hilly land must be constantly on the lookout for new gullies and must use every means for preventing their enlargement. No attempt should be made to crop the very badly gullied areas. It would be best to reforest these as rapidly as possible. 1918} WASHING OF SOILS AND METHODS OF PREVENTION 537 This will effectually prevent further erosion, and after a few years will be a source of profit as well. Fig. 18 shows a grove of black locust grown on gullied rolling hill land on the farm of J. C. B. Heaton, in Johnson county. Care must be taken to prevent shallow draws from becoming deep, untillable gullies. A somewhat common method is to scatter straw in them, or to build dams of straw across them at frequent intervals. This is often done in wheat fields after seeding in the fall. Such a method may serve to check the velocity of the water and to catch the sediment, but frequently the run-off is so great that the water 1 washes around the ends of the dams or carries the straw down the draw and deposits it at the base. These dams are sometimes held in place by rows of stakes driven across the draw. FIG. 18. BLACK LOCUSTS GROWING ON BADLY ERODED LAND Farm of J. C. B. Heaton, Johnson county. A better plan, used a great deal in some parts of the state, is to keep these draws well sodded, at least until they are so well filled that there is little danger of gullies forming (Fig. 19). The sod binds the soil particles together, while the top growth checks the velocity of the water, causing the suspended sediment to be deposited. In time the draw becomes filled so that it may be cropped, but it should be seeded down again if there is danger of a gully forming. Almost any grass 538 BULLETIN No. 207 [April, FIG. 19. SODDED DRAW IN MERCER COUNTY FIG. 20. DAMS OP STRAW HELD BY WOVEN WIRE FENCING, MASON COUNTY that forms a tough sod will answer the purpose, timothy, red-top, and blue grass being quite satisfactory. This method is practiced very suc- cessfully in some parts of the state. 1 The grass may be mowed for hay. 'Some owners in renting their land insert a clause in the lease forbidding the plowing up of these draws. 1918] WASHING OF SOILS AND METHODS OF PREVENTION Where the gullies are small, the matter of filling them is a simple one, altho care and perseverance are required to keep them filled. If it is desirable to crop the field soon, and the gullies< are not too deep, they may be filled with the plow and scraper in a comparatively short time and at little expense. A depression, or draw, must not be left where the gully formerly was, or it will be a constant source of trouble. Dams of earth, stone, concrete, or straw held by woven wire (Fig. 20 ) are sometimes constructed across a gully in order to catch the sedi- ment and thus fill the gully and prevent its later formation in the same draw. In many cases this method has been very satisfactory. It may be used for draws as well as for gullies. FIG. 21. A GULLY IN CENTRAL ILLINOIS This gully started less than forty years ago, and is now from 100 ta 150 feet wide and from 25 to 65 feet deep. The construction of these dams should vary with the size of the gully and the amount of water flowing thru it. If the gully is small, an earth dam constructed as shown in Fig. 22, may be all that is necessary to prevent its enlargement (see Fig. 23). If the gully is large, and the volume of water considerable, a concrete dam should be used which, in addition to the tile, has a spillway over which the excess water may flow. An apron of concrete should be placed under the spillway to prevent the undermining of the dam. Fig. 24 shows a detailed plan that may be used as a guide in the construction of a concrete dam. The concrete should be well rein- forced and anchored on each side. The tile may be placed so as to run either under the dam or thru it. Care must be taken to build the dam 540 BULLETIN No. 207 [April, with sufficient strength to resist the pressure of the water. The con- crete should extend at least two feet below the bed of the stream, or below the frost line. Figs. 25 and 26 show concrete dams in place. FIG. 22. DAM OF EARTH The tile, both vertical and horizontal, must be large enough to allow the water to flow away without any of it going over the dam, as that will ruin it. The gully produced by a waterfall is one of the hardest to fill, since the fall of the water gives it great eroding power, making it very difficult to stop its undermining action. As such gullies generally occur where the field is in grass, there is a comparatively small amount of sediment carried, and consequently the filling goes on but slowly. The problem is to stop the recession. Straw and brush should be placed under the fall and weighted down with stones or sod, or held in place with stakes to prevent their being washed away. Dams of straw or brush should be placed at intervals below the fall, and even a solid dam of concrete where the gully passes into another field may be of much service in completely filling it in time. FIG. 23. DITCH IN CHAMPAIGN COUNTY FILLED BY MEANS OF EARTH DAM The gully was six feet deep and sufficiently wide at the bottom for a team and wagon to stand crosswise. It was filled in less than ten years. 1918] WASHING OF SOILS AND METHODS OF PREVENTION 541 2.0'. TV (3) FIG. 24. DETAILED PLAN FOR A CONCRETE DAM (1) View from above; (2) Looking upstream; (3) Section. C Upstream apron for preventing under wash ing. D Spillway apron of concrete. E-E Con- crete abutments for bracing the main dam. F Steel reenforcing rods, horizontal and vertical. G Permanent tile for draining ditch when filled with sediment (the size of the tile will vary with the needs, and may run under the spillway if the ditch is not deep). II An opening may be left in the dam to take care of the water under ordinary conditions and reduce the size of the pond above the dam; this opening should be closed when the ditch is filled with sediment to that level. S42 BULLETIN No. 207 [April, rt 5 O bJD i-* >^ . . "o a r 01 2 ' &, '1918] WASHING OF SOILS AND METHODS OF PREVENTION ^ ' 543 RECLAMATION EXPERIMENTS JOHNSON COUNTY EXPERIMENT FIELD AT VIENNA, ILLINOIS In the spring of 1906 the Agricultural Experiment Station of the University of Illinois purchased sixteen acres of land in Johnson county near Vienna. The whole area, with the exception of about three acres, had been abandoned because so much of the surface soil had been washed away, and there were so many gullies that further cultivation was unprofitable (Fig. 27). The land was bought for the purpose of reclaiming it and studying different methods of reducing erosion. HIM I I w FIG. 27. VIEW OF LAND IMMEDIATELY ADJOINING THE VIENNA EXPERIMENT FIELD When the land was purchased, gullying had not gone very far. (See Fig. 28.) Part of the land was occupied by scrub trees, persimmon, elm, and sassafras, and by blackberry and other brush. This was removed and used in making brash dams in the ditch running north and south across the middle of the field. Some of the gullies were from four to five feet deep, so that the first step in reclaiming the land was to fill them and make the slopes more uniform. This was accomplished with plows and scrapers. The soil was extremely low in organic matter, the subsoil being exposed on about one-fourth of the field. These conditions were responsible for a large part of the run-off, the low productiveness of the soil, and the injury to crops by drouth. In two places, about a square rod of the underlying rock was exposed. 544 BULLETIN No. 207 [April, The field was divided into five series, A, B, C, D, and E, as shown in Fig. 29. The division, it will be noticed by the contour lines, was more or less natural to the lay of the land. Series A, B, C, and D, together with divisions and borders, occupy about thirteen acres, and Series E about three acres. A, B, and C were divided into four plots each ; D, into three plots. For each series a somewhat different system of reclamation was planned in order not only to study the prob- lems of reducing erosion, but also to determine which system of reclam- ation was best under these conditions, as indicated by the crop yields. Series A includes the steepest part of the area and contained many gullies. These were filled and the area was terraced at vertical inter- vals of five feet. Near the edge of each terrace, which had a slight slope, a small ditch was placed, so that the water could be carried to a natural outlet at the side of the field without doing much washing. Each terrace was cropped as a separate area. In two places in Series B were several small gullies, none of which was more than eighteen inches deep. On this series the embankment method was used, except at the steepest part, where two hillside ditches were made for carrying away the run-off. Series C was washed badly but contained only small gullies. On this series an attempt was made to prevent, washing by incorporating organic matter in practicable amounts. In the spring of each year, with the exception of two years, manure at the rate of about eight loads per acre was turned under for corn. Series D lies just across the hollow from Series C, and was washed to about the same extent. As a check against the various methods for reducing erosion, Series D was farmed in the most convenient way, without any special effort being made to prevent washing. -*i;c * ^.TTV***;^ ^" - - FIG. 28. SAME AS FIG. 27, BUT TEN YEARS LATER 1918} WASHING OF SOILS AND METHODS OP PREVENTION 545 These series (A, B, C, and D) were not entirely uniform. As already stated, some parts were washed worse than others, and sections of the lower part of the field had been affected by soil material brought from the higher land. When the field was secured, this higher land had a very low productive capacity, as shown by the yield of 9.7 bushels of corn on Series D, and 11.1 bushels on Series C, in 1906, the first year. Many spots would grow little or nothing. Series E was badly eroded and gullied and was not cropped. An attempt was made to fill the gullies by putting brush into them and seeding to grass, but this was not wholly successful. The area above the gullies was soon covered with vegetation, so that there was little soil material washed into the ditches to aid in filling them. However, the grass and brush prevented the gullies from becoming larger. Limestone was applied to the entire field at the rate of two tons per acre. No other mineral plant food was applied. Corn, cowpeas, wheat, and clover were grown every year in the order named, as a FIG. 29. MAP OF UNIVERSITY OF ILLINOIS SOIL EXPERIMENT FIELD AT VIENNA Showing location of the series and the approximate contour lines (5-foot in- tervals). The sharp bends in contour lines show where largo gullies were located. 546 BULLETIN No. 207 [April, four-year rotation, together with additional cover crops when nec- essary. The corn stalks, the second growth of clover, and the cowpeas were turned back into the soil. When clover failed, soybeans were sub- stituted, but these did not make a large growth (seldom more than an ordinary second growth of clover) , and were turned under. Tables 9, 10, and 11 give the yields of the crops by plots on each series. TABLE 9. YIELDS OF CORN IN SOIL EXPERIMENTS, VIENNA FIELD: 1906-1915 (Bushels per acre) Year Plot A B C D 1906 i 42.1 18.6 11.1 9.7 1907 4 17.8 24.8, 31.0 No plot 1908 3 25.0 44.0 31.5 31.1 1909 2 30.8 41.5 41.2 13.5 1910 1 52.5 36.0 27.7 8.0 1911 4 30.0 31.9 36.5 No plot 1912 3 13.7 37.5 10.8 24.4 1913 9 24.6 36.4 41.8 8.2 1914 1 30.8 13.5 22.6 3.7 1915 4 24.5 14.8 32.1 No plot Average . 29.2 29.9 28.6 14.1 TABLE 10. YIELDS OF WHEAT IN SOIL EXPERIMENTS, VIENNA FIELD: 1906-1915 (Bushels per acre) Year Plot A B C D 1906 1 1907 2 8.9 10.6 9.4 5.6 1908 1 8.9 6.2 8.5 1.5 1909 4 7.3 7.0 12.0 No plot 1910 3 11.5 18.8 16.7 7.8 1911 . 2 13.1 19.6 20.1 3.7 1912 1 3.0 2.8 1913 4 6.9 10.0 12.5 No plot 1914 3 9.3 14.7 11.1 8.4 1915 2 8.5 15.3 14.8 5.1 Average. 8.0 11.6 11.7 4.6 'Oats were sown instead of wheat, but they did not grow high enough to be harvested. TABLE 11. YIELDS OF CLOVER IN SOIL EXPERIMENTS, VIENNA FIELD: 1907-1915 (Tons per acre) Year Plot A B C D 1907 1908 1909 1910 1911 1912 1913 1914 1915 3 2 1 4 3 2 1 4 3 .75 .20 . 1.11 1.04 .29 .30 .40 .10 Clover turned under .46 - 1.08 1.20 No plot Failure Soybeans turned under 1.09 .78 1.81 .14 Soybeans turned under Sweet clover turned under Soybeans turned under Average .62 1.00 .90 .21 1918] WASHING OF SOILS AND METHODS OF PREVENTION 547 It is difficult to compare the results obtained from the various methods of treatment on the different series because of the variation in the soil, but it can be said that any system that conserves the soil will aid in maintaining the crop yields. Table 12 gives by periods the crop yields obtained under the different methods of management. TABLE 12. ANNUAL CROP YIELDS OBTAINED UNDER DIFFERENT METHODS OF MANAGEMENT TO 'REDUCE EROSION: VIENNA FIELD Years Terrace (A) Embankments and hillside ditches (B) Organic matter, deep contour plowing, and contour planting (C) Check (D) Corn (Bushels per acre) 1906-08 1909-11 1912-15 28.3 37.7 23.4 29.1 36.5 25.6 24.5 35.1 26.8 20.41 10.71 12.12 Average 29.2 29.9 28.6 14.1 Wheat (Bushels per acre) 1907-09 1910-12 1913-15 Average 8.3 9.2 7.6 7.9 13.7 13.3 10.0 12.3 12.8 3.51 5.71 6.3 8.6 11.6 11.7 5.3 Clover (Tons per acre) 1907-8-10-13 .62 1.00 .90 .21 a Two-year average. 2 Three-year average. The average yield of corn for 1912 to 1915 was less than for 1906 to 1908 in every case except where the organic matter was increased. This was due in part to the three dry seasons during the 1912 to 1915 period. Series -C and D were on either side of a draw extending north and south, C facing west and D east. Series C received manure in addition to the cowpeas and residues turned under, and every effort was made to prevent washing, tho this was not successful in all cases. Series D, of which no particular care was taken, is now almost worth- less because of gullying (Fig. 30). Table 13 gives the average yields for the four series, based on all comparable yields. TABLE 13. AVERAGE OF COMPARABLE YIELDS, VIENNA FIELD: 1906-1915 Crops Years Series A B C D Corn (bu. per acre) 7 7 3 31.4 9.0 0.68 32.4 12.7 0.97 27.9 11.7 0.80 14.1 4.6 0.21 Wheat (bu. per acre) Clover (tons per acre) The average yield of corn for the protected series (A, B, and C) was 30.6 bushels per acre, as against 14.1 bushels for series D ; wheat yielded 11.1 bushels in comparison with 4.6 bushels, and clover 0.82 ton in comparison with 0.21 ton. 548 BULLETIN No. 207 [April, FIG. 30. VIEW OP PART OF SEKIES D, 1916, VIENNA EXPERIMENT FIELD Note badly eroded condition. The best biennial legume for soil improvement on eroded land is sweet clover, because as already stated, it catches readily and makes a large growth of both top and root. The second season's growth begins sufficiently early so that if desired a considerable amount may be plowed under for corn the same season (see Fig. 31). The comparison between Series C and Series D may be somewhat in favor of C since C received some manure. Series A, however, was washed as badly as D in all except the northeast and southeast parts, and aside from terracing received the same treatment as D. The dif- ference in yields here is almost as striking as between C and D. As an average of the comparable yields, A produced 31.4 bushels of corn per acre and D, 14.1 bushels ; A produced 9.0 bushels of wheat and D, 4.6 bushels ; A produced .68 ton of clover and D, .21 ton. Reclaiming and reducing erosion resulted in an increase of 17.3 bushels of corn per acre, 4.4 bushels of wheat, and .47 ton of clover hay. Figuring corn at 60 cents and wheat at 80 cents per bushel and clover hay at $7 per ton, the value of the increase due to reclamation and control of erosion for one four-year rotation is $17.19. These three crops represent the total yield per acre, as the cowpeas were turned under. The average annual gain per acre is $4.30; which would mean $172 a year from forty acres, and $1,720 in ten years from forty acres. The expense of reclaiming the land, which for series A and B consisted in filling gullies and building terraces and embankments, 1918] WASHING OF SOILS AND METHODS OF PKEVENTION 549 was approximately $18 on 5.8 acres. About two-thirds of this amount was spent on Series A, which had been completely abandoned when the tract was purchased and was badly gullied and more difficult to ter- race. Series C and D required but little work, since they contained only a few small gullies and no terracing was done. The value of the crops removed from Series A during the first rotation was $66.08, or at the rate of $26.43 per acre for four years, or $6.61 per acre per annum. The crops of cowpeas are not included in the above. If $6 per ton is allowed for the cowpea hay, the value of the crops will be increased about $4.50 per acre, making approxi- mately $11.11 per acre on this formerly abandoned land. The approx- imate costj of maintaining the terraces on Series A was not over fifty cents per acre per annum, and much less on Series B. This increase in returns pays for all labor of filling gullies and building terraces and maintaining them, and leaves a fair profit on each field where washing is largely prevented and the soil conserved. Series A is in a condition to be cultivated for years to come if properly cared for, while Series D cannot be cropped profitably in its present condition. FIG. 31. SWEET CLOVER ON VIENNA EXPERIMENT FIELD About 30 inches high, May 31, 1914. 550 BULLETIN No. 207 [April, 1918 Increasing and maintaining the organic matter, using cover crops, keeping the land in pasture and meadow as much as possible, and prac- ticing deep contour plowing and planting are the most practical means for reducing soil washing in Illinois. If these methods are practiced, much of the badly eroded land can be cultivated with profit. FIG. 32. CORN ON VIENNA EXPERIMENT FIELD Upper Section Series D, 1914; yield 3.7 bushels. Lower Section Series C, 1914; yield 22.6 bushels. AUTHOR INDEX 557 AUTHOR INDEX PAGE Allyn, O. M., ami Burlison, W. L. Soybeans and Cowpeas in Illinois 1-20 Allyn, O. M., and Burlison, W. L. Yields of Winter Grains in Illinois 95-110 Burlison, W. L., and Allyn, O. M. Soybeans and Cowpeas in Illinois 1-20 Burlison, W. L., and Allyn, O. M. Yields of Winter Grains in Illinois 95-110 Bin-rill, Thomas J., and Hansen, Eoy. Is Symbiosis Possible between Legume Bacteria and Non-Legume Plants?. 111-181 Carmichael, W. J., Grindley, H. S., and Newlin, C. I. Diges- tion Experiments with Pigs with Special Reference to the Influence of One Feed upon Another, and to the In- dividuality of Pigs 53-94 Chambers, W. H., Prucha, M. J., and Weeter, H. M. Germ Content of Milk as Influ- enced by the Utensils. . . .215-257 Crandall, Charles S. Seed Pro- duction of Apples 184-213 Grindley, H. S., Carmichael, W. J., and Newlin, C. I. Diges- tion Experiments wifh Pigs with Special Reference to the Influence of One Feed upon Another, and to the Individ- uality of Pigs 53-94 Gunderson, A. J., Pickett, B. S., Watkins, O. S., and Ruth, W. A. Field Experiments in Spraying Apple Orchards in 1913 and 1914 427-509 (Justafson, A. F., and Mosier, J. G. Washing of Soils and Methods of Prevention. .511-550 Hanson, Roy, and Burrill, Thomas J. Is Symbiosis Possible be- PAGE tween Legume Bacteria and Non-Legume Plants! ...111-181 Mother, Edna. The Grasses of Illinois , 259-425 Mosier, J. G., and Gustafson, A. F. Washing of Soils and Methods of Prevention. . .511-550 Newlin, ,C. I., Grindley, H. S., and Carmichael, W. J. Diges- tion Experiments with .Pigs with Special Reference to the Influence of One Feed upon Another, and to the Individ- uality of Pigs 53-94 Pickett, B. S., Watkins, O. S., Ruth, W. A., and Gunderson, A. J. Field Experiments in Spraying Apple Orchards in 1913 and 1914 427-509 Prucha, M. J., and Weeter, H. M. Germ Content of Milk as Influenced by the Factors at the Barn 21-52 Prucha, M. J., Weeter, H. M., and Chambers, W. H. Germ Con- tent of- Milk as Influenced by the Utensils .... . .215-257 Ruth, W. A., Pickett, B. S., Wat- kins, O. S., and Gunderson, A. J. Field Experiments in Spraying Apple Orchards in 1913 and 1914 427-509 Watkins, O. S., Pickett, B. S., Ruth, W. A., and Gunderson, A. J. Field Experiments in Spraying^ Apple Orchards in 1913 and 1914 427-509 Weeter, H. M., and Prucha, M. J. Germ Content of Milk as In- fluenced by the Factors at the Barn 21-52 Weeter, II. M., Prucha, M. J., and Chambers, W. H. Germ Con- tent of Milk as Influenced by the Utensils 215-257 558 VOLUME 14 INDEX (The headings in capitals are subjects of entire 'bulletins) PAGE Acacia 119, 135, 139, 140 armata 129, 131, 136 floribunda. . .123, 129, 131, 134, 136 from California 129, 131, 136 linifolia 129, 131, 136 longi folia 129, 131, 136 melanoxylon 131, 136, 154 semperflora 129, 131, 136 Alfalfa, see Medicago Alnus 145, 149-50, 160 glutmosa 150 Amorpha canescens.131, 134, 135, 137 Amphicarpa 119, 135, 139 monoica 123, 131, 133, 134, 135, 137, 149 Anthyllis 135 vulneraria 133 Apple blotch 452, 454-57,493, 499 Sprays for 506-07 Apple flea- weevil 452, 453 Apple-leaf roller 452, 453 APPLE OECHARDS, FIELD EXPERIMENTS IN SPRAYING, IN 1913 AND 1914 427-509 Index to bulletin 509 Apple scab, on foliage .. 452, 453, 472 on fruit 454-57, 460-71, 488, 490-93, 497-99 Sprays for 50507 APPLES, SEED PRODUCTION IN 183-213 Number of seeds 185 Opinions regarding 185-87 Orchard varieties 189-200 Records 187-89 Under controlled pollination . . 211-13 See also Crab apples Arachis 119, 135, 139 hypogoea 123, 131, 134, 135, 136, 149, 153 Archips rosaceana 452 Bacteroids 121-22 Banding trees for control of cod- ling moth 447, 448, 504 Ba-ptisia 119, 139 tinctoria 123, 131, 134, 135, 136 Barley, Ground, for pigs. .75, 77, 79- 80, 81 Winter, Tests with 99, 106-08 Barns, see Dairy barns Bean, see Phaseolus Bean, wild, see Strophostyles PAGE Bitter rot of apples, Sprays for 507, 508 Blotch, Apple, sec Apple blotch Blue grass as cover crop 527-28 Bordeaux injury, see Russet, Bordeaux Bud moth, Spray for 505 Burn, Lime sulfur. 429, 445, 448, 474- 78, 480-86, 489, 494-98, 501, 504 Canterworm, Spray for 505 Cassia, 119, 135, 139, 140 chamaccrista. . . .123, 127, 131, 134, 135, 136, 137 (note) medsgeri 136 (note) nictitans 136 (note) Ceanothus 115, 145, 152, 160 americanus 145-48 Clover as cover crop 527-28 Nitrogen content of 532 See also Trifolium Clover, Sweet as cover crop 527-28 for improvement of eroded land 532. 548 Nitrogen content of 532 See also Melilotus Codling moth. .429, 432-40, 441, 44o- 48, 452, 454-57, 460, 461, 463- 71, 472-89, 490-93, 495-97, 499, 502-04 Sprays for 477-79, 506-08 Connecticut river basin, Run-off from 518 Corn Ground, for pigs 62-63, 68, 69, 77, 79-80 Inoculation 151 Nitrogen requirements S32-33 Corn stalks, Nitrogen content of. 532 Cover corps to reduce erosion . . 52(5-28 Cowpea as cover crop 527 grown in Illinois 1-20 Nitrogen content of 532 Sec also Viana Crap apples, Seed production iu 200-11, 212, 213 Crab grass as cover crop 527 Cracking of apples 437, 438 Cross-inoculation 125-40, 160 Cowpea X several generic groups 131-33 INDEX 559 PAGE Carman's method 125, 127, 133, 134, 153 Grouping by scrological tests and cultural differences. .137-40 Lens X several generic groups 133 Vigna X Acacia 129-31 Vigna X Cassia 127-29 Ctirculio 460-71, 474, 476, 478-88, 490, 492, 493-97, 499 Sprays for 506-07 Cutler, 111., Tests of winter rye, barley, emmer, and oats.. 106-08 Cycas 115, 145, 150, 152, 160 rcvoluta 148-49 Dairy barns used in experiments on germ content of milk . . . 26-29 Dams, Construction of 539-42 De Kalb, 111., Tests of winter rye and barley 99, 101 De Kalb experiment field 97 Desmodium 119, 135, 139 canescens 123, 131, 134, 135, 136, 149, 154 illinoense 134, 135, 136 Digestion experiments, see Pigs Elaeagnus 115, 145, 149-50, 152, 160 Embarrass river basin, run-off from 518 Erosion 511-50 Cause 519-20 Changes in physical character of soil due to 525 Cover crops to reduce 526-28 Effects 522-25 Filling and preventing gullics.536-42 Increasing organic-matter con- tent to reduce 528-33 Kinds 519-21 Methods of reducing 526-36 Reclamation experiments at Vienna 543-50 Terraces to reduce 535-36 Tiling to reduce 535 Tillage to reduce 533-35 Fail-field, 111., Variety tests of winter wheat 104-06, 107 False indigo, see Baptisia Flora, 111., Spraying experiments 449-57 Fail-field experiment field 97 Fenugreek, see Trigonella FranTcia bruncliorslii 145 ccanothi 145, 148 subtilis 145 Frg*-eye fungus, see Leaf spot Carman's method of cross-inocu- lation 125, 127, 133, 134, 153 PAGE Genista 119, 139 tinctorM 123, 131, 134, 135, 136, 154 Germ content of milk, studies of 21-52, 215-57 Glycine. . .'. 119, 127, 135, 139 hispida 123, 134, 135, 137, 149, 153, 154 GRAINS, YIELD OF WINTER, IN ILLINOIS 95-110 GRASSES OF ILLINOIS, THE 259-425 Bibliography 419 Descriptions and distribution 275-419 Index to common names .... 423-25 Index to scientific names. . .420-23 Key to genera of 269-74 Griggsville, 111., Spraying experi- ments 458-89 Gullying, see Erosion Hog peanut, see Amphwarpa Illinois, Area 513 Rainfall 517 Illinois river basin, Run-off from 518, 519 Japan clover, see Lcspedeza Kaskaskia river basin, Run-off from 518 Kidney vetch, see Anthyllis Lathyrus 119, 127, 139 latifolius 133, 136 odoratus 123, 136, 154 Lead plant, see Amorpha canescens Leaf burning 434, 445, 484 of tip and edge 465, 468, 470, 474, 475, 479, 481, 486 Leaf spot 452, 453, 460, 463, 467, 468, 470, 494 Spray for 506 Legume bacteria, see Pseudo- monas radicicola LEGUME BACTERIA AND NON-LEGUMES, POSSI- BLE SYMBIOSIS BE- TWEEN 111-81 Legumes as cover crop 526-28 to improve eroded land 531-32 Lcguminosae, Histology of nod- ules of 141 Lens 119, 135, 139 esculcnta 135, 136 Lentil, .s'ec Lens Lcspedesa 119, 135, 139 striata 123, 131, 134, 135, 136 virf/inica 134, 135, 136 Lupine, see Liipinvs 560 VOLUME 14 PAGE Lupinus 119, 135 perennis 134, 135, 137, 149 Mains, Experiments in seed pro- duction 187-189, 200-213 Mangum terrace 53536 Medicago 119, 127, 135, 139 falcata 136 hispida 136 lupulina 134, 136 sativa 123, 133, 134, 136, 148 Mdilotus 119, 127, 135, 139 alba 123, 133, 134, 136, 148, 152, 153, 154 indica 134, 136 oificinalis 134, 136 Middlings 61-63, 67, 69 Milk as source of bacteria 231-33 Experiments to determine germ content . 21-52, 215-57 at New York Agricultural Experiment Station . 25-26, 217 Barns used 26-29 Conclusions 51, 257 Methods of study. .30-32, 219-20 Kesults 32, 46-48 Germ content Bacteria added by barn factors 48-50 of all milk at different milk- ings 43-46 of individual samples 33-41 of milk of different animals.41-42 Souring of 217 Utensils Bacteria in 219-20, 221-31 Bottle filler, influence on germ content 248-50 Bottles, bacteria in 241-44 Influence at barn 245-47, 250-54, 256 Influence on germ content. 221-44 Previous studies 218-19 Sterilization 30, 226 Wash water as source of bacteria 233-40 Washing 219 MILK, GERM CONTENT OF I. AS INFLUENCED BY THE FACTORS AT THE BARN 21-52 II. AS INFLUENCED BY UTENSILS 215-57 Mimosa 135 pudica 133 Morning glory, Attempted in- fection with sweet-clover bac- teria 157 Hucuna 135, 139 utilis 123, 131, 134, 135, 136 Mustard, Attempts to grow leg- PAGE ume bacteria on 115 Myrica 145, 149-50, 160 gale 145 Neoga, 111., Spraying experi- ments 432-48 New York (Geneva) Agr. Exp. Sta., Investigations of germ content of milk 25-26, 217 Nitrogen Content of different crops. . . 532 Loss from erosion 522-25 Needed by soils subject to erosion 531 Requirements for corn 532-33 Nitrogen fixation 115 Non-legumes concerned in ... 145-50 By legumes, bibliography. .. 161-78 Nodule bacteria, varieties of. ... 125-40, 160 Nodules, Non-legume root, Bibli- ography 179-81 of the Leguminoeae, Histol- ogy 141-44 Non-legume root nodules, Bibliog- raphy 179-81 Nozzles for spraying. .. .445-56, 448, 456-57, 499-501 Oat straw, Nitrogen content of.. 532 Winter 106-08 Onobrychis sativa 149 Orchards, see Spraying experi- ments Orchestes canus 452 Ornithopus 135 sativus 137, 149 Partridge pea, see Cassia Pea, see Pisum Peanut, see Arachis Phcbseolus 119, 127, 135, 139 angustifolia 137 multiflorus 133, 137 milgaris 123, 133, 134, 137, 148-49, 151, 154 Phosphorus, Loss from erosion. 522-25 Phyllosticta solitaria 452 PIGS, DIGESTION EXPERI- MENTS WITH 53-94 Chemical composition of feces 56-57, 60-61, 73, 76-77 of feeds 56-57, 73 Coefficients of digestibility 61-65, 75-80 Average 66, 88 of ground barley 81 of ground barley and ground corn 83 of ground corn 68, 82 of middlings 67 of middlings and ground corn 69 showing individuality of pigs 71, 86 INDEX 561 PAGE Conclusion 89-90 Digestion harness (illus) 94 Digestion stalls 55-56, 91-93 Individuality as to thoroncss of digestion 70-72, 85-87 Influence of one feed upon di- gestibility of another 65-70, 80-85, 89 Objects 55 Plan of experiments 1913-14 55-56 1914-15 72-73 Rations 56,72-73, 88 Weight of feces.. .57, 58-59, 74-75 of feeds 58-59, 74-75 of pigs 58-59, 74-75 of urine 58-59, 74-75 of water 58-59, 74-75 Piitum 119, 127, 135, 139 arvense 123, 133, 135, 148 sativum 133, 134, 135, 136, 152 xatii'iim arvcnsc 136 Podocarpus 145, 160 Potomac river basin, Run-off from 518 Pscudomonas radicicola The organism 116-23 Experiments attempting infec- tion of non-legumes. .155-59, 160 Rainfall in Illinois 517 and run-off 518-19 Robinia pseudo-acacia. .131, 133, 134, 135, 137, 153 Run-off, see Rainfall Russet, Bordeaux. . .429, 432, 437-38, 440, 445, 449-51, 454-57, 460-65, 470-71, 474, 475, 477-84, 486, 489, 494, 499-502 Lime sulfur 435, 460, 467- 70, 474, 480 Rye as cover crop 520 to improve eroded land 531 Winter 99, 101, 106-08 San Jose scale, Spray for 505 Savannah river basin, Run-off from 518 Scab, see Apple scab Sensitive plant, see Mimosa Serradella, see Ornithopus Sheet washing, see Erosion Soil Changes produced by erosion. . 525 Organic-matter content of Illi- nois 529 subject to erosion 522-23 Soil survey of Illinois, Area of broken and hilly land. . . .514-15 Sooty blotch.... 460-71, 472, 474-89, 491, 493, 497, 498 PAGE Sprays for 506-07 SOYBEANS AND COWPEAS IN ILLINOIS , 1-20 Soybean Culture 4 Harvesting of 5, 6 Inoculation 5 Tests with 6-20 See also Glycine Sphaeropsisf malorum .452, 460 Spoon river basin, Run-off from. 518 Spraying experiments in apple orchards 427-509 Amount of spray, Varying. 455, 457 Applications Fourth summer 436-37, 4S1, 483, 484 General effectiveness 490, 493-94 Times of 431, 505-08 Nozzles Effectiveness of standard... 445-46, 448 Varying size of. .456-57, 499-501 Objects of 1913-14 experiments 429 Orchards Flora, 1913 451 Griggsville, 1913 458 1914 472 Neoga, 1913 432 1914 441 Pressure, Varying ....437-39, 445, 454-55, 457, 499-501 Recommendations 505-08 Records 431 Sprays for apple trees Acetate of lead with copper ferrocyanide 487, 488, 489 Arsenate of lead Brands of . . .434-36, 442-45, 484-86, 495 Effectiveness 490-94 Formula 431 Paste and powered compared 464, 465, 471 used alone . . .434-35, 442-44, 447-48, 471 with Bordeaux and lime sul- fur 461, 476 with lime sulfur . .434-36, 442-45, 448, 464, 471 Bordeaux Effectiveness 490-94 Formula 430 with lime sulfur, see Sprays for apple trees, Lime sul- fur Sec also Russet Calcium hyposulfite. . .445, 448, 495 562 VOLUME 14 PAGE Copper ferrocyanide 445, 448, 471, 495 prepared in different ways. . ' 466, 467-68, 498-99 ' with acetate of lead. 487, 488, 489 with arsenate of lead 437 Lime sulfur compared with atomic sulfur and soluble sulfur 468, 469, 486, 487 Effectiveness 490-94 Formula for commercial .... 430 for home-made 430-31 Various strengths 467, 481, 482, 504 Lime sulfur and Bordeaux Interchanged 461, 463, 475-77, 501-02 Light and heavy applications 469, 470, 478, 479-81 Relative values of 459-60, 473-75, 494-95 Special, for codling moth . . . 502-04 Drenching 477-79, 502 . for delayed broods. . .446-47, 503 Fourth summer spray for second brood 436-37 Sulfur, Atomic 445, 448, 468, 469, 471, 486, 487, 498 Soluble 445, 448, 468, 469, 471, 486, 487, 498 Tuber tonic 445, 448, 498 Strawberry plants, Attempted in- fection with sweet-clover bacteria 157, 159 Strophostyles 119, 135, 139 helvola 133, 134, 135, 137, 154 Sweet pea, see Lathyrus Swine, see Pigs Symbiosis between legume bac- teria and non-legumes. .. .111-81 Experiments 152-59 Tankage 63, 80 Tent caterpillar, Spray for 505 Terraces for cultivated slopes. 535-36 PAGE Tick trefoil, see Dcsmodinm Tiling to reduce erosion 535 Tillage for land subject to erosion 533-35 Tomato, Attempted infection with sweet-clover bacteria 155-57 Trifolium 119, 127, 135, 139 alcxandrianum 136 hybridum 136 incarnatum 136 medium 136 pratense 123, 134, 148, 152, 153, 154 pratense perenne 136 repens 136 Trigonella 119, 135, 139 foemim-graecum . 133, 134, 135, 136, 149 Urbana, 111., Variety tests of win- ter wheat 101-04 Urbana experiment field 97 Velvet bean, see Mucuna Vetch, see Vicia Vicia 119, 127, 135, 139 angustifolia 136 daysiecarpa 136 faba 123, 133, 136, 154 sativa . 136 villosa 122, 123, 134, 136, 148 Vienna, 111., Reclamation experi- ment at 543-50 Vigna 119, 127, 135, 139, 140 sinensis 123, 127, 129, 131, 134, 135, 136, 149, 153, 154 WASHING OF SOILS AND METHODS OF PREVEN- TION 511-50 Wheat, Winter Characteristics of vari- eties 109-10 Tests of 97-110 Wheat straw, Nitrogen content of 532 Winter grains, see Grains Yellow leaf... 438, 474, 475, 479, 486 UNIVERSITY OF ILLINOIS-URBANA