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 UNiVERSITYGFjyJNOjS, 
 
UNIVERSITY OF ILLINOIS 
 
 Agricultural Experiment Station, 
 
 BULLETIN NO. 99. 
 
 SOIL TREATMENT FOR THE LOWER 
 ILLINOIS GLACIATION. 
 
 BY CYRIL G. HOPKINS AND J. E. READHIMER. 
 
 URBANA, ILLINOIS, MARCH, 1905. 
 
SUMMARY OF BULLETIN No. 99. 
 
 1. It is possible to adopt a profitable system of farming that will make the 
 soils of southern Illinois permanently productive. Page 563 
 
 2. Chemical analyses show these soils to be quite deficient in nitrogen and 
 organic matter, very deficient in phosphorus, only moderately well supplied with 
 potassium, and markedly acid. Page 563 
 
 3. The effects of tile drainage upon these soils under certain conditions of 
 season and treatment are very suggestive. Pages 565, 570, 575 
 
 4. Very beneficial results with legumes are obtained from the use of lime. 
 
 Pages 573, 586 
 
 5. The results obtained from experiments strongly confirm the universal 
 experience as to the very great value of farm manure upon this type of soil. 
 
 Pages 569, 571, 589 
 
 6. By the use of liberal applications of lime and thorough inoculation with the 
 proper nitrogen-gathering bacteria, clover can be' grown on this type of soil with 
 profit. Pages 571, 573, 587 
 
 7. While under certain conditions largely increased yields of oats and of corn 
 have been obtained from the use of potassium, it is still questionable if commercial 
 potassium can be used with profit. Pages 576, 588, 589 
 
 8. Phosphorus is the limiting element in these soils and must be used liberally 
 in order to make them permanently productive. Pages 568, 577, 585, 592 
 
 9. A liberal use of legumes, to supply organic matter and nitrogen, must be 
 an essential part of any practical and economical system that ever becomes success- 
 ful in the permanent improvement of southern Illinois soils. Pages 585, 594 
 
 10. It is good farm practice to remove large quantities of plant food from the 
 soil provided as large or larger amounts be returned when necessary. Page 594 
 
 11. This bulletin will be sent free of charge to any one interested in Illinois 
 agriculture, upon request to E. Davenport, Director Agricultural Experiment 
 Station, Urbana, Illinois; and if so requested, the name of the applicant will be 
 placed upon the permanent mailing list of the Experiment Station, so that all 
 subsequent bulletins will be sent to him as they are issued. 
 
 Recommendations Page 594 
 
SOIL TREATMENT FOR THE LOWER 
 ILLINOIS GLACIATION. 
 
 BY CYRIL G. HOPKINS, CHIEF IN AGRONOMY AND CHEMISTRY, AND J. E. READ- 
 HIMER, SUPERINTENDENT OF SOIL EXPERIMENT FIELDS. 
 
 The chief reason for the thorough investigation of Illinois soils (now 
 in progress) is to bring about methods of farming which shall at least 
 permanently maintain the present high crop yields of our best soils 
 and which shall increase the fertility of our poorer soils to their maxi- 
 mum profitable productive capacity. These investigations have been 
 in progress only three years, but results are rapidly being obtained 
 which are certainly of very great value to Illinois agriculture, and it is 
 believed that these results should be promptly reported to the farmers 
 and land owners of the state, even though final conclusions cannot as 
 yet be drawn on all questions involved. 
 
 All of the most important soils are already being investigated, and 
 the plans adopted and now in operation include a detail soil survey of 
 the entire state and a thorough investigation of every type of soil found, 
 by chemical and physical analysis , by exact pot culture experiments 
 under controlled conditions, and so far as necessary by field experiments 
 conducted in different sections of the state and under actual field con- 
 ditions. 
 
 Among the most important results already obtained are those from 
 the University soil experiment fields located in different parts of southern 
 Illinois, especially on the common prairie soil in the Lower Illinois 
 Glaciation, the oldest glaciated area in the state. This great area of 
 agricultural land of depleted fertility includes the counties of Fayette, 
 Effingham, Jasper, Marion, Clay, Richland, Washington, Jefferson, 
 Wayne, Edwards, Perry, Franklin, and Hamilton, and parts of as many 
 more surrounding counties. The principal type of soil in this area is a 
 gray silt loam. It is not strictly a clay soil, although it is quite commonly 
 spoken of as "clay," sometimes as "white clay." Silt consists of soil 
 particles smaller than sand, and impalpable, but it is not sticky, plastic 
 clay. 
 
 The chemical composition of this gray silt loam of the Lower Illinois 
 Glaciation, as given on page 20 of Circular No. 68 (a copy of which 
 can be obtained free of charge upon request to the Illinois Experiment 
 Station, Urbana, Illinois), shows this soil to be only moderately well 
 supplied with potassium, quite deficient in nitrogen and organic matter, 
 exceedingly deficient in phosphorus, and markedly acid. 
 
 563 
 
564 BULLETIN Xo. 99. [Murclt, 
 
 Four University soil experiment fields are located upon this type of 
 soil: 
 
 (1) The Edgewood Field, one mile northwest of Edgewood, Effing- 
 ham County, on the farm of Mr. Samuel Bartley. 
 
 (2) The Odin Field, one mile southwest of Odin, Marion County, 
 on the farm of Col. N. B. Morrison. 
 
 (3) The DuBois Field, one and one-half miles northwest of DuBois 
 (Bois Station), Washington County, on the farm of Mr. A. A. Hinkley. 
 
 (4) The Cutler Field, five miles northwest of Cutler, Perry County, 
 on the farm of Mr. W. E. Braden. 
 
 The Edgewood field lies beside the Baltimore & Ohio Southwestern 
 Railroad and the Odin field beside the Illinois Central Railroad. Either 
 of these fields can be reached by a twenty minutes' walk from the station, 
 along the railroad. 
 
 The DuBois field contains about three acres (aside from co-operative 
 experiments), and the three other fields about fifteen acres each, includ- 
 ing the exact, experiment plots, division strips, and borders. 
 
 THE EDGEWOOD FIELD. 
 
 The Edgewood field consists of three parts, known as the West 
 Field, the East Field, and the North Field. 
 
 THE WEST FIELD AT EDGEWOOD. The west field contains two series 
 of seven plots each, one series (plots 101 to 107), being not tile-drained, 
 and the other series (plots 201 to 207), being tile-drained. Aside from 
 the drainage, these two series of plots are treated and cropped alike. 
 Experiments on this field were begun in 1896, the tile having been laid 
 in the spring of that year. Three strings of tile were laid across all the 
 plots in the 200 series, at a distance of 50 feet apart. Plot 101 was 
 known to be somewhat better land than the average of the field, because 
 of some surface wash which it once received from adjoining land. The 
 original experiments were planned by Dean Davenport, and they in- 
 cluded the work with tile drainage and also the green manure experi- 
 ments with cow peas on plot 1 and buckwheat on plot 2, and the sub- 
 soiling on plot 7. After two or three years the management of the field 
 was turned over to Professor Holden, who had the sodium nitrate 
 applied in 1899. The authors of this bulletin are responsible for the 
 management of the field since 1900, including the plan of soil treatment 
 adopted in 1901 and applied for the 1902 crop. 
 
 This field was originally laid out in eight plots, with no division 
 strips between the plots, and this arrangement was continued till the 
 fall of 1901, when the number of plots was reduced to seven, with half- 
 rod division strips between the plots. The yields reoorted in Table 1 
 are all given for the plot boundaries as now fixed, computations having 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 565 
 
 been made, where necessary, from the old plot yields. Thus, plot 1 is 
 identical in both systems, no computations being required; but the 
 present plot 2 consists of three-fourths of the former plot 2 and one- 
 fourth of the former plot 3, and the yields are computed accordingly. 
 A careful study of the two systems of plotting and of the actual and 
 computed yields convinces us that no appreciable inaccuracy is intro- 
 duced by this rearrangement, and it is a decided advantage, in that it 
 provides for half-rod divisions between the plots, thus guarding against 
 the treatment of one plot being allowed to affect the crop yields on an 
 adjoining plot, and also making it possible to have the records of each 
 plot continuous from the beginning, in 1896, up to the present time. 
 Corn, oats, and legumes have been grown on this field as the principal 
 crops during the past nine years, and hereafter a three-year rotation is 
 to be practiced on the field as follows: 
 
 First year, corn. 
 
 Second year, oats. 
 
 Third year, legume. 
 
 On certain plots, in addition to the regular legume grown in the 
 third year of the rotation, a legume* catch crop is grown as often as 
 possible, such as cow peas seeded in the corn when it is laid by. Lime 
 (as ground limestone, unburned), phosphorus (as steamed bone meal), 
 and potassium (as potassium chlorid or sulfate), and manure, are 
 applied to plots as indicated. Table 1 shows the different kinds of 
 treatment applied and the crop yields obtained from the west field at 
 Edge wood for nine years, 1896 to 1904, inclusive. 
 
 During the nine years, Mr. Samuel Bartley has had immediate charge 
 of the field work. He has continually reported that there is a good flow 
 of water from the tile outlet whenever the ground is saturated and also 
 that, as a general rule, the soil on the tile-drained plots works more 
 easily and keeps in better condition than that on the undrained plots. 
 As a rule, the tile-drained land has produced larger yields than the 
 undrained land, plot 101 being excepted for reasons mentioned above. 
 
 In 1896 very satisfactory weather conditions obtained and an excel- 
 lent crop of com was secured, especially on the drained land. Some 
 benefit is strongly indicated from subsoiling on land not tile-drained. 
 
 In 1897, owing to drought and chinch bugs, the corn crop was a 
 failure. 
 
 In 1898 a good crop of cow peas was grown, although very little 
 effect is seen from drainage or from the previous subsoiling. 
 
 In 1899 the corn was markedly better on the tile-drained land, 
 although the crop was poor. Nitrate of soda (sodium nitrate) applied 
 to plots 5 and 6 at the rate of 300 pounds per acre, and to plot 7 at the 
 rate of 200 pounds per acre, produced no apparent effect on yields of corn. 
 (Nitrate of soda costs about $2.50 per hundred pounds.) 
 
566 
 
 BULLETIN No. 99. 
 
 Marr1i. 
 
 TABLE J. CROP YIELDS IN SOIL EXPERIMENTS. EDGEWOOD WEST FIELD. 
 
 Plot 
 No. 
 
 Gray silt loam prairie, 
 Lower Illinois Glaciation. 
 
 Series 100. 
 Not drained. 
 
 Series 200. 
 Tile draineU. 
 
 Soil treatment applied. 
 
 1896 Corn bushels per acre. 
 
 1 
 
 None (cowpeas turned under) 
 
 Cowpeas. 
 
 Cowpeas. 
 
 2 
 3 
 
 None (buckwheat turned under) 
 None 
 
 Buckwheat. 
 34.9 
 
 Buckwheat. 
 37.7 
 
 4 
 
 None 
 
 42.5 
 
 54.3 
 
 5 
 
 None 
 
 41.7 
 
 51.2 
 
 6 
 
 None 
 
 37.0 
 
 50.9 
 
 7 
 
 Subsoiled . 
 
 46.5 
 
 54.0 
 
 1897 Corn, bushels per acre. 
 
 1 
 
 Green manured 
 
 (1896) 
 
 4.3 
 
 2.1 
 
 2 
 
 Green manured 
 
 (1896) . 
 
 1.9 
 
 1 .4 
 
 3 
 
 None 
 
 
 3.7 
 
 3.7 
 
 4 
 
 None 
 
 
 8.5 
 
 8.1 
 
 5 
 
 None 
 
 
 11.4 
 
 15.9 
 
 6 
 
 None 
 
 
 10.2 
 
 12.9 
 
 7 
 
 None . . . . . 
 
 
 6.4 
 
 8.7 
 
 
 
 
 
 
 1898 Cowpeas, bushels per acre 
 
 1 
 
 2 
 3 
 
 None (cowpeas turned under) 
 None (buckwheat turned under) 
 None 
 
 Cowpeas. 
 Buckwheat. 
 18.8 
 
 Cowpeas. 
 Buckwheat. 
 19.6 
 
 4 
 
 None . 
 
 21.5 
 
 22.9 
 
 5 
 
 None . 
 
 22.3 
 
 26.3 
 
 6 
 
 None . 
 
 14.6 
 
 22.5 
 
 7 
 
 None . . 
 
 14.9 
 
 17.3 
 
 1899 Bushels corn per acre. 
 
 1 
 
 Green manured 
 
 (1898) . 
 
 25 6 
 
 20 7 
 
 2 
 3 
 
 Green manured 
 None . 
 
 (1898) 
 
 15.4 
 11.4 
 
 16.4 
 16.5 
 
 4 
 
 None . 
 
 
 12.3 
 
 26 
 
 5 
 
 Sodium nitrate 
 
 
 11.3 
 
 25 3 
 
 6 
 
 Sodium nitrate 
 
 
 12 9 
 
 22 S 
 
 7 
 
 Sodium nitrate . 
 
 
 16.3 
 
 23.5 
 
 1900 Oats, bushels per acre. 
 
 1 
 
 2 
 3 
 
 4 
 5 
 6 
 
 7 
 
 None ... 
 
 34.0 
 33.0 
 30.0 
 36.0 
 40.0 
 36.0 
 3G.O 
 
 22 
 38.5 
 30.0 
 36.5 
 36.0 
 31.5 
 36.0 
 
 None . 
 
 None . 
 
 None 
 
 None 
 
 None 
 
 None 
 
 
 1901 Clover, tons per acre 
 
 1 
 
 2 
 3 
 
 4 
 5 
 
 6 
 
 7 
 
 None 
 
 .74 
 .16 
 .04 
 .07 
 .38 
 .27 
 .24 
 
 .28 
 .14 
 .05 
 .09 
 1.04 
 .67 
 .58 
 
 None 
 
 None 
 
 None 
 
 None 
 
 None . 
 
 None . 
 
 
1905.) SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 567 
 
 TABLE 1. CONTINUED. CROP YIELDS IN SOIL EXPERIMENTS. 
 
 FIELD. 
 
 EDGEVVOOD WEST 
 
 Soil 
 plot 
 
 No. 
 
 Gray silt loam prairie, 
 Lower Illinois Glaciation. 
 
 Soil treatment applied. 
 
 Series 100. 
 Not drained. 
 
 Series 200. 
 Tile drained. 
 
 1902 Corn, bushels per acre 
 
 1 None 11.3 
 
 2 None 8.1 
 
 3 Legume 9.3 
 
 4 Legume, lime 11.3 
 
 5 Legume, lime, phosphorus 14:9 
 
 6 Legume, lime, phosphorus, potassium .. 17.1 
 
 7 Lime, phosphorus, potassium . . 21 . 5 
 
 1903 Oats, bushels per acre. 
 
 1 None 12.5 
 
 2 None 10.9 
 
 3 Legume ' 12.2 
 
 4 Legume, lime 21 . 2 
 
 5 Legume, lime, phosphorus 31.6 
 
 6 Legume, lime, phosphorus, potassium . . 24 . 4 
 
 7 Lime, phosphorus, potassium. . 20.6 
 
 1904 Corn, bushels per acre. 
 
 1 Manure 60.4 
 
 2 Manure 52.0 
 
 3 Legume 29.0 
 
 4 Legume, lime 40 . 9 
 
 5 Legume, lime, phosphorus 43.0 
 
 6 Legume, lime, phosphorus, potassium . . 52.5 
 
 7 Lime, phosphorus, potassium. . 52.6 
 
 14.1 
 16.7 
 15.1 
 24.9 
 33.7 
 32.1 
 33.2 
 
 6.6 
 
 9.4 
 
 7.2 
 
 16.2 
 
 35.3 
 
 37.5 
 
 35.0 
 
 59.6 
 58.0 
 27.8 
 44.4 
 59.2 
 62.1 
 61.3 
 
 In 1900 a good crop of oats was obtained, but there are no differences 
 of special interest among the yields from the different plots, except, 
 possibly, the discordant results from plots 1 and 2, as compared with 
 the yields of corn for the previous year. 
 
 In 1901 the clover, which had been seeded with the oats in 1900, 
 produced a very poor crop, but quite a marked increase in yield occurred 
 on plots 5, 6 and 7, which had been treated with sodium nitrate two 
 years previous. These results suggested to the writers the probable 
 acidity of this type of soil. The nitrogen applied in the sodium nitrate 
 was much less in amount than the nitrogen removed in the crops grown 
 in 1899 and 1900, and it seemed very improbable that sufficient nitrogen 
 should remain in the soil to affect a third crop, especially as it had produced 
 no apparent effect upon either the corn or oats, although applied in per- 
 fectly soluble form. 
 
 Sodium nitrate contains 50 percent more sodium than nitrogen. 
 Sodium is a strongly alkaline element, and most of this element would be 
 
568 BULLETIN No. 99. [March, 
 
 left in the soil when the nitrogen was removed by crops. This would 
 unite with the soil acids, and in places may have been sufficient to correct 
 the soil acidity to the depth of a few inches, thus making a much more 
 suitable condition for the growth and multiplication of the nitrogen- 
 gathering bacteria on the clover roots, in case there were any brought 
 with the clover seed or any already present in the soil. Subsequent 
 experiments with the use of lime on this soil type (referred to in the 
 following pages) strongly confirms this theory as to the effect produced 
 by the sodium. (In addition to this, sodium nitrate is a soluble mineral 
 salt which possesses some corrosive power by which the mineral elements 
 of plant food, phosphorus and potassium, might be liberated from the 
 soil to some extent.) 
 
 It should be understood that the legume treatment for 1902 was 
 cow peas seeded in the corn that season. Of course, they could not be 
 expected to benefit the 1902 corn crop. The season was very dry and 
 the cow peas made but little growth, consequently they produced little, 
 if any, effect upon the oat crop in 1903. One marked effect from soil 
 treatment in the 1902 crop is the higher yield produced by phosphorus 
 on plot 5 as compared with plot 4, which was treated the same as plot 
 5, except for the phosphorus. Phosphorus made an average gain of 
 4.6 bushels of corn on the undrained land, and a gain of' 13.7 bushels 
 on the tile-drained land. A still more striking effect was produced by 
 the tile drainage. On several plots the tile-drained land produced twice 
 as much as the undrained land, the maximum increase being from 14.9 
 to 33.7, or a gain of 18.8 bushels, on plot 5. 
 
 The results obtained with oats in 1903 agree with the previous year's 
 work in showing a marked increase by phosphorus, this gain amounting 
 to 10.4 bushels of oats on the undrained land, and 19.1 bushels on the 
 drained land. All tile-drained plots to which phosphorus had been 
 applied yielded larger crops than the corresponding undrained plots, 
 but it is noticeable that all plots not receiving phosphorus produced 
 smaller yields on the tile-drained land than on undrained land. There 
 seems to be no explanation for this, unless it is possibly in the fact that 
 these tile-drained plots produced the larger yields of 1902 and conse- 
 quently retained smaller amounts of available plant food for the 1903 
 crop. 
 
 In order to bring the rotation on the west field into line with the 
 general system adopted for the three Edgewood fields, corn was again 
 grown in this field in 1904, oats being grown upon the north field and a 
 regular legume crop upon the east field, thus allowing each of the three 
 crops to be grown every year. 
 
 The season of 1904 was a fairly satisfactory one for the corn crop. 
 Even with some allowance for the fact that plot 101 is somewhat better 
 land than the average of the field, as mentioned above and as indicated 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 569 
 
 by every year's results, the results obtained from the manure plots* 
 strongly confirm the universal experience as to the very great value of 
 farm manure upon this type of soil, although slightly better results 
 were obtained where both phosphorus and potassium were applied, 
 especially on tile-drained land. Aside from this most satisfactory result 
 produced by the farm manure, there are three other results of much 
 importance: (1) Linre (as ground limestone) added to the legume 
 treatment increased the yield by 11.9 bushels on the undrained land 
 and by 16.6 bushels per acre on the tile-drained land.f (2) Phosphorus 
 produced an increase of 14.8 bushels on the tile-drained land, although 
 only 2.1 bushels gain was produced by phosphorus on undrained land. 
 (3) On undrained land potassium produced a gain of 9.5 bushels when 
 used in connection with lime and phosphorus, although only 2 to 3 
 bushels gain was produced by potassium on the corresponding tile-drained 
 plots. But perhaps the most important result obtained in 1904 is the 
 marked effect of tile drainage upon this type of soil under certain condi- 
 tions of treatment. If we disregard plot 101, tile drainage produced an 
 appreciable gain in every case, excepting with legume treatment only 
 on plot 3. (It may be stated here that the legume treatment on plot 3 
 previous to 1904 consisted of very poor catch crops of cow peas in 1902 
 and 1903, whose effect upon the soil would be very slight. On plots 
 4, 5, and 6, the legume catch crops have made better growth.) By far 
 the most marked effect of tile drainage was on plot 5 (legume, lime, 
 phosphorus), where a gain of 16.2 bushels of corn per acre was produced 
 by the tile drainage. While final conclusions ought not to be drawn as 
 yet, data are fast accumulating which tend to show that one of the 
 important effects of tile drainage is to render more accessible to the 
 plant the immense store of potassium existing in the subsoil. Where 
 we have corrected the acid in the soil with ground limestone so that 
 legumes grow better (the bacteria which live in the tubercles on the 
 
 *NOTE. In the modified plan of the Edgewood experiments it was designed 
 to reserve plot 1 (in each series) as a check plot, to which no special treatment 
 should be applied, while plot 2 was to receive six tons of farm manure per acre 
 every three years to be applied for the corn crop. (Our standard rate of applying 
 farm manure on all regular soil experiment fields is two tons per acre per annum, 
 all applied in one year in the rotation, usually preceding a corn crop.) Through a 
 misunderstanding, manure was applied to plot 1 as well as to plot 2 in each series 
 on the west field at Edgewood in the spring of 1904, and the rate of application was 
 12 tons per acre instead of 6 tons. Because of this, plot 3 is taken as the check 
 plot, this plot having received no special treatment, excepting that in 1902 and 
 
 1903 it grew very poor catch crops of cow peas, which were turned under, and in 
 
 1904 a fair catch crop of cow peas which, however, were pulled and removed from 
 the land. Hereafter no special treatment will be applied to 103 or 203. 
 
 fAttention is called to the fact, however, that plot 3 usually gave somewhat 
 smaller yields than plot 4 in previous years, even before lime was applied. 
 
570 BULLETIN No. 99. [March, 
 
 roots of the legumes and get nitrogen from the air do not thrive in acid 
 soils), and have then grown legume crops and catch crops, and have 
 also applied phosphorus, as on plot 105, we have thus made provision 
 for all plant food except potassium, but still the crop produced in 1904 
 (plot 105) was only 43 bushels of corn per acre. When potassium was 
 added (plot 106) the yield was increased to 52.5 bushels, but where 
 tile drainage was put in (plot 205) the yield was increased from 43 to 
 59.2 bushels without applying potassium, thus indicating that tile 
 drainage not only enables the crop to obtain a good supply of potassium 
 from the abundant store which is known to exist n the subsoil, but 
 that still other benefits were produced by the tile drainage, for even 
 where potassium was applied (plots 6 and 7) the tile-drained plots yielded 
 nearly 10 bushels more than the corresponding undrained plots. The 
 fact that every plot to which phosphorus has been applied (5, 6, and 7) 
 has given a larger yield on tile-drained land during the entire three years, 
 is certainly strong evidence in favor of tile drainage. To be sure, the 
 tile may produce but little effect during dry seasons, when they are not 
 needed to remove surplus water, or even during extremely wet seasons, 
 when heavy rains are so frequent that even the tile-drained land remains 
 saturated much of the time. 
 
 THE EAST FIELD AT EDGEWOOD. This field consists of two series 
 (300 and 400), of 10 plots each. A three-year rotation of corn, oats, 
 and clover has been grown on this field during the past three years. 
 The entire field is tile-drained. Commercial nitrogen in the form of 
 dried blood has been used on certain plots, as indicated in the table. 
 Phosphorus and potassium were applied in the same forms as used on the 
 west field. The limed plots on series 300 received ground limestone, 
 while those of the 400 series received fresh slaked lime. 
 
 The nitrogen, phosphorus and potassium were applied previous to the 
 1902 corn crop, but no lime was applied till after that crop had been 
 harvested. Some previous differences were known to exist among the 
 plots on this field, and these differences show very distinctly in the first 
 corn crop. Plots 1 and 2 in each series had been given heavy applica- 
 tions of farm manure some years previous to 1902. By using plot 1 as 
 a check plot and plot 2 for lime only, we avoid getting any exaggerated 
 results from the other kinds of soil treatment, and, incidentally, have 
 obtained some data relating to the lasting effect of farm manure. 
 
 Table 2 gives the yields of corn, oats, and clover from all of the 
 plots on this field for three years. It will be noted that in 1903 the 
 two series were harvested as one. 
 
1DU5.] SOIL TltEATMENT FOH THE LOWER ILLINOIS GLACIATION. 571 
 
 TABLE 2. CROP YIELDS IN SOIL EXPERIMENTS. EDGEWOOD EAST FIELD. 
 
 Soil 
 
 Gray silt loam prairie, 
 Lower Illinois Glaciation 
 
 1902 Corn, bu. 
 
 1903 
 
 1904 Clover, tons. 
 
 plot 
 
 
 
 Oats, bu. 
 
 
 
 
 
 
 
 No. 
 
 Soil treatment applied. 
 
 Series 
 300. 
 
 Series 
 400. 
 
 average. 
 
 Series 
 300. 
 
 Series 
 400. 
 
 1 
 
 None 
 
 40.9 
 
 44.3 
 
 33.9 
 
 1.13 
 
 2.33 
 
 2 
 
 Lime. . 
 
 34 8 
 
 47 7 
 
 40.6 
 
 1.70 
 
 2.18 
 
 3 
 
 Lime, nitrogen 
 
 20.9 
 
 23.1 
 
 39.1 
 
 1.68 
 
 2.01 
 
 4 
 
 Lime, phosphorus 
 
 25.7 
 
 22.8 
 
 42.8 
 
 1.93 
 
 2.00 
 
 5 
 
 Lime, potassium 
 
 22.1 
 
 32.4 
 
 38.3 
 
 1.55 
 
 2.01 
 
 6 
 
 Lime, nitrogen, phos. . . . 
 
 21.6 
 
 25.2 
 
 41.1 
 
 2.36 
 
 2.91 
 
 7 
 
 Lime, nitrogen, potass. . . 
 
 17.7 
 
 13.6 
 
 37.2 
 
 2.17 
 
 2.61 
 
 8 
 
 Lime, phos., potassium. . . 
 
 30.3 
 
 17.7 
 
 48.1 
 
 2.69 
 
 2.52 
 
 9 
 
 Lime, nit., phos., potass. . 
 
 27.2 
 
 17.5 
 
 46.7 
 
 2.67 
 
 2.74 
 
 10 
 
 Nit., phos., potass.. 
 
 27.9 
 
 15.9 
 
 49.1 
 
 1.88 
 
 2.39 
 
 No conclusions are to be drawn from the 1902 corn crop, aside from 
 the fact that a marked effect was produced on plots 1 and 2, in each 
 series, owing to the previous heavy application of farm manure already 
 referred to. The crop suffered from a severe wind storm, and it was 
 much injured by chinch bugs, especially on plots 7 to 10, in the 400 
 series. 
 
 The results obtained from the oat crop in 1903 show that the effect 
 of the farm manure on plots 1 and 2 had been equaled or exceeded by the 
 applications made to several other plots, especially where phosphorus 
 was included in the treatment. Indeed, the crop yields for 1903 and 
 1904 are better appreciated when we bear in mind that in 1902 plots 
 1 and 2 produced a yield of corn 15 bushels higher than the yield of 
 any other plot, as an average of both series, whereas in 1903 the oat 
 crop on the check plot (No. 1) is 13 to 15 bushels lower than on the 
 highest yielding plots (8, 9 and 10). 
 
 The results from the clover crop in 1904 are exceedingly interesting 
 and valuable, even though some of the data are confusing and many 
 questions are not fully settled. Of greatest importance, perhaps, is the 
 simple fact that more than two and one-half tons per acre of well cured 
 pure red clover hay were produced on some of these plots on soil which 
 is very generally considered incapable of growing clover successfully. 
 Indeed, many farmers who visited this experiment field expressed great 
 surprise at seeing such a crop of clover, stating that they had never 
 before seen clover grown so successfully on this type of soil. Aside 
 from the special treatment given the different plots, it should be remem- 
 bered that all of these plots are well tile-drained and that the clover was 
 well inoculated with the proper nitrogen-gathering bacteria, by methods 
 already explained in Bulletin No. 94, "Nitrogen Bacteria and Legumes," 
 a copy of which will be sent to any one'free of charge, upon application. 
 
572 BULLETIN No. 99. [March, 
 
 The individual plot yields indicate some things, but the single year's 
 results do not justify definite conclusions. It will be observed, for 
 example, that the 400 series yielded more than the 300 series, on most 
 plots. One might suppose that this is due to the fact that burned lime 
 was applied to the 400 series, while ground limestone was used on the 
 300 series; but this difference is marked on the unlimed plots (1 and 10), 
 as well as on most of the limed plots. Plot 401, to which neither lime 
 nor plant food had been applied, yielded 2.33 tons, as against 1.13 tons 
 on plot 301. The only explanation suggested for this difference is the 
 fact that plot 401 is nearest to the barnyard and probably has received 
 more farm manure than any other plot in the field. The high yield on 
 plot 402 may be due in part at least to the same reason. No explana- 
 tion is offered for the difference between plots 310 and 410, as Mr. Bart- 
 ley, who has owned and farmed this land for more than thirty years, 
 is sure that no manure has been applied to any part of this field, aside 
 from the first two or three plots in each series. 
 
 It would be expected that burned lime would produce a greater 
 increase in the crops for the first year or two than would be produced 
 by the ground limestone, more especially where the mineral elements, 
 phosphorus and potassium, are not applied, for the reason that ground 
 limestone produces practically no effect except to correct the acidity 
 of the soil and thus encourage the multiplication and activity of the 
 nitrogen-gathering bacteria, while the burned lime not only produces 
 this same effect, but it also acts as a soil stimulant, or soil destroyer, 
 attacking and destroying the organic matter and decomposing the 
 mineral constituents, and thus liberating plant food from the soil. The 
 use of ground limestone to correct acidity and increase the fixation of 
 atmospheric nitrogen is certainly altogether legitimate and commend- 
 able, but to use burned lime to force the soil to give up plant food more 
 rapidly than it would otherwise do, thus producing an increase in the 
 first few crops, but ultimately leaving the soil more impoverished than 
 before the lime was applied, is not thought to be advisable or profit- 
 able in the long run, unless the soil contains comparatively large stores 
 of unavailable plant food and abundant organic matter, which is cer- 
 tainly not the case with this soil. It is perhaps worthy of notice that 
 where lime, phosphorus, and potassium were all applied (plots 8 and 9), 
 the yield of clover was about the same in each series, averaging slightly 
 higher with the ground limestone; but where one or both of these 
 elements were omitted, the yield was then larger where burned lime was 
 used. 
 
 The north field at Edgewood is devoted to experiments to determine 
 the comparative agricultural value of steamed bone meal and ground 
 rock phosphate, applied in different amounts; and the east field and the 
 north field combine experiments to determine the amounts of lime or 
 
1905.] SOIL TEEATMENT FOR THE LOWER ILLINOIS GLACIATIOX. 573 
 
 ground limestone which can be used with greatest profit on this soil. 
 From the analysis of the soil and the results thus far obtained from 
 field experiments, we recommend at least two tons to the acre of ground 
 limestone. Larger applications will do no harm, but will probably 
 produce quicker results and will certainly last longer. Probably it will 
 be necessary to continue to apply ground limestone at the rate of a ton 
 to the acre every five or six years, but further results are necessary to 
 determine this point. The north field at Edgewood was started more 
 recently than the other fields, and the data thus far obtained are not 
 sufficient to justify their discussion at this time. 
 
 Plate 1 shows the red clover growing upon plot 304, to which ground 
 limestone and steamed bone meal have been applied, which produced 
 about two tons of clover hay to the acre. 
 
 Plate 2 shows the effect of lime upon the alfalfa growing upon one 
 of the border strips of the Edgewood field, lime having been applied 
 on the right, and no lime on the left. Similar results, showing the very 
 marked benefit of lime or ground limestone upon alfalfa in several other 
 places and also upon last spring's seeding of red clover on the north field, 
 are sufficient to fully demonstrate the importance of using some form 
 of lime for growing clover on this type of soil. (See, also, illustrations 
 from DuBois field.) 
 
 PLATE 1. CLOVER CROP WITH LIME AND PHOSPHORUS TREATMENT. 
 SOIL EXPERIMENT FIELD, 1904. 
 
 EDGEWOOD 
 
574 
 
 BULLETIN No. 09. 
 
 f March , 
 
 I 
 
 a 
 
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1905.] SOIL TREATMENT FOB THE LOWER ILLINOIS GLACIATION. 575 
 
 THE ODIN FIELD. 
 
 The Odin Soil Experiment Field is located on the west side of the 
 Illinois Central Railroad, about one mile southwest of Odin, Marion 
 County, on the farm of Col. N. B. Morrison. The original field contains 
 40 fifth-acre plots, arranged in four series (100 to 400), of 10 plots each, 
 one-half of each series (plots 1 to 5) is not drained, while the other half 
 (plots 6 to 10) is tile-drained. Plots 1 and 2, especially in series 300 
 and 400, are better land than the average, being on the lower side of the 
 field. All the remaining plots are believed to be fairly uniform. 
 
 A four-year rotation is being followed on the field: 
 
 First year, corn. 
 
 Second year, oats. 
 
 Third year, wheat. 
 
 Fourth year, cow peas. 
 
 In 1902 corn was grown in place of wheat in series 300. On plots 
 1 and 6 no treatment is applied. On all other plots cow peas are grown 
 as a catch crop, in the corn, after the oats, and after the wheat, these 
 catch crops always being turned under. During the first rotation (four 
 years), the full crop of cow peas is also being turned under on these plots. 
 Lime, phosphorus, and potassium are applied as indicated in Table 3. 
 
 In 1902 very poor crops were produced, drouth, chinch bugs, and 
 poor soil combining to produce this effect. Some slight improvement 
 is shown where phosphorus was applied, and where corn was grown the 
 improvement with both phosphorus and potassium is more noticeable. 
 
 In 1903 the crops were even-poorer than in the previous year. (Hun- 
 dreds of acres of wheat in southern Illinois were not cut.) Phosphorus 
 produced a slight increase in the yield of oats and a very marked in- 
 crease in the yield of wheat, especially on tile-drained land (plots 208 
 and 209), where, the increase was from 2.1 bushels to 13.4 bushels, or a 
 gain of 11.3 bushels. It will be observed that with legume-lime-phos- 
 phorus treatment, 5.8 bushels were obtained on undrained land, that this 
 was increased to 13.4 bushels, or 7.6 gain, by tile drainage, and that it 
 was increased to 14.0 bushels, or 8.2 gain, by adding potassium, thus 
 suggesting that tile drainage may serve to aid the crops in .drawing 
 potassium from the large supply in the subsoil, by encouraging deeper 
 rooting. This coincides with some similar indications seen in the results 
 from the Edgewood field; but, aside from this single wheat plot and 
 three plots of oats in 1904, no appreciable benefits have as yet resulted 
 from the tile drainage at Odin. It is true that -this tile has been in only 
 three years and that tile usually becomes more and more effective for 
 eight or ten years; also that the first two years were almost crop failures, 
 with very little rainfall, and the third year so wet that even the tile- 
 drained land contained too much water most of the time. It would be 
 premature to draw any definite conclusions at this time as to the value 
 
576 
 
 BULLETIN No. 99. 
 
 [March, 
 
 
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1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 577 
 
 of tile drainage in this soil. One thing, however, is sure: When the 
 ground is saturated with water, a good stream flows out of the tile, at 
 Edgewood, at Odin, and at DuBois. Greater benefits from, tile drainage 
 may be obtained, perhaps, after a deep rooting biennial crop, like red 
 clover, has been grown. (After next season, cow peas are to be sub- 
 stituted for oats and red clover for the fourth year cow peas, in the 
 rotation at Odin, making the rotation corn, cow peas, wheat, and clover.) 
 
 Referring again to Table 3, it will be seen that the oat crop in 1903 
 was markedly benefited by the addition of potassium to the other treat- 
 ment, the yield being increased by 17.2 bushels on undrained land and 
 by 16.6 bushels on the tile-drained land. 
 
 In 1904 favorable weather conditions prevailed, aside from the ex- 
 cessive rainfall, which during the spring and early summer was more 
 than could be removed by the tile under present conditions. The wheat 
 was considerably damaged by rust, more especially on the better plots. 
 Some very marked results were obtained from the use of phosphorus 
 for wheat, the yield being increased from about 10 bushels to 21.5 bushels, 
 making a gain of 11 bushels on undrained land and 12 bushels on tile- 
 drained land. According to the wheat buyer's grading, the phosphorus 
 also inproved the quality of the wheat, so that the selling price was 
 advanced from 80 cents to 90 cents a bushel. Potassium produced an 
 additional gain of more than 3 bushels and advanced the selling price 
 to 95 cents a bushel. With corn and oats, phosphorus produced no 
 appreciable effect, but a noticeable increase was produced by lime on 
 both corn and oats, and a good gain was made on the oat crop by the 
 legume treatment alone; but the most marked effect was produced by 
 the potassium on the corn crop, the yield of corn being increased on 
 undrained land from 44.1 to 66.6, a gain of 22.5 bushels, and, on the 
 tile-drained land, from 45.9 to 64.1, a gain of 18.2 bushels, making an 
 average gain of more than 20 bushels. It is especially instructive to 
 note the difference in yield between the crops on the untreated plots 
 and those receiving full treatment. For this comparison the tile-drained 
 plots are the more reliable, as they are more nearly uniform. 
 
 Thus, the yield of wheat was increased from 6.7 to 25.4, a gain of 
 18.7 bushels. Furthermore, the yield of wheat was increased in 1903 
 from .6 to 15.2, a gain of 14.0 bushels, making a total increase of 33.3 
 bushels in two years. The yield of corn was increased from 29.4 to 
 64.1, a gain of 34.7 bushels. In 1902 the yield of corn was increased 
 9.2 bushels on one series and 8.9 bushels on the other; and in 1903 it 
 was increased 6.3 bushels. This would make 24.4 bushels, or a total 
 gain of 59.1 bushels for the four crops. The yield of oats was increased 
 from 25.1 to 43.1, a gain of 18 bushels. In 1902 the yield of oats was 
 increased 5.5 bushels, and in 1903 it was increased 20.8 bushels. This 
 would make 26.3 bushels, or a total gain of 44.3 bushels in three years. 
 
578 
 
 BULLETIN No. 99. 
 
 March. 
 
 PLATE 3. WHEAT CROP (2.1 bu.) WITH LEGUME AND LIME TREATMENT: 
 SOIL EXPERIMENT FIELD, 1903. 
 
 ODIN 
 
 PLATE 5. WHEAT CROP (9.6 bu.) WITH LEGUME AND LIME TREATMENT: 
 SOIL EXPERIMENT FIELD, 1904. 
 
 ODIN 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 579 
 
 PLATE 4. WHEAT CROP (13.4 bu.) WITH LEGUME, LIME, AND PHOSPHORUS TREAT- 
 MENT: ODIN SOIL EXPERIMENT FIELD, 1903. 
 
 PLATE 6. WHEAT CHOP (21.5 bxi.) WITH LEG r ME, T.IME, AND PHOSPHORUS TREAT- 
 MENT: ODIN SOIL EXPERIMENT FIELD, 1904. 
 
580 
 
 BULLETIN No. 99. 
 
 [March, 
 
 PLATE 7. CORN CROP (29.4 bu.) WITH No SOIL TREATMENT: ODIN SOIL EXPERI- 
 MENT FIELD, 1904. 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 581 
 
 PLATE 8. CORN CROP (64.1 bu.) WITH LEGUME, LIME, PHOSPHORUS, POTASSIUM 
 TREATMENT: ODIN SOIL EXPERIMENT FIELD, 1904. 
 
582 
 
 BULLETIN No. 99. 
 
 [March, 
 
 PLATE 9. Cow PEA CROP WITH No SPECIAL SOIL TREATMENT: ODIN SOIL EXPERI- 
 MENT FIELD, 1904. 
 
 As shown in Table 3, the cow pea crop was turned under on all 
 plots except the checks, the plan being to turn under one full crop of 
 cow peas on each series for the benefit of the land, this being in addition 
 to the catch crops grown. It was observed, however, that the cow pea 
 crop responds to soil treatment as markedly as any other crop, being 
 especially benefited by the addition of limestone and potassium. In 
 order to obtain some data as to the effect of soil treatment on cow peas, 
 one-thousandth acre plots were harvested from several field plots in 
 1904. Plot 207, with only legume treatment, produced 3.4 bushels of 
 shelled peas per acre; while plot 210, with legume, lime, phosphorus, 
 potassium treatment, produced 22.3 bushels per acre, a gain of 19.1 
 bushels. The three years' results from corn, oats, and wheat are sum- 
 marized in Table 4. 
 
1905.] Son, TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 583 
 
 PLATE 10. Cow PEA CROP WITH LEGUME. LIME, PHOSPHORUS, POTASSIUM TREAT- 
 MENT: ODIN SOIL EXPERIMENT FIELD. 1904. 
 
 TABLE 4. TOTAL YIELDS FOR THREE YEARS: ODIN SOIL EXPERIMENT FIELD. 
 
 Soil treatment. 
 
 Corn, bu. 
 
 Oats, bu. 
 
 Wheat, bu. 
 
 None . 
 
 57 
 
 45.4 
 
 7.3 
 
 Legume, lime, phosphorus, potassium. . . . 
 
 116.1 
 
 89.7 
 
 40.6 
 
 Increase 
 
 59.1 
 
 44.3 
 
 33.3 
 
 It will be seen that the effect of the full treatment has been to more 
 than double the yield of corn, to nearly double the yield of oats, and to 
 produce a total yield of wheat five and one-half times as large as was 
 produced on the untreated land. Furthermore, the untreated land is 
 growing poorer, while the treated land is growing richer, much more 
 plant food having been applied than has been removed in the crops. 
 This subject will be discussed more fully after the data from the DuBois 
 and Cutler fields have been given. 
 
584 
 
 BULLETIN No. 99. 
 
 [March, 
 
 THE DuBois FIELD. 
 
 The DuBois Soil Experiment Field is located about one mile north- 
 west of DuBois (Bois Station), Washington County, on the farm of 
 Mr. A. A. Hinkley. It contains 20 tenth-acre plots, arranged in two 
 divisions of 10 plots each, one division being tile-drained and the other 
 not drained. A four-year rotation is being followed upon this field, 
 namely : 
 
 First year, corn. 
 
 Second year, oats. 
 
 Third year, wheat. 
 
 Fourth year, clover. 
 
 The clover is seeded on the wheat land in the spring of the third year. 
 
 The soil treatment applied and the crop yields obtained during the 
 first three years are shown in Table 5. 
 
 TABLE 5. CROP YIELDS IN SOIL EXPERIMENTS: DuBois FIELD. 
 
 Soil 
 plot 
 No. 
 
 Gray silt loam prairie. 
 Lower Illinois Glaciation. 
 
 1902 Corn, bu. 
 
 1903 Oats, bu. 
 
 1904 Wheat, bu. 
 
 Soil treatment applied. 
 
 Not 
 drained. 
 
 Tile- 
 drained. 
 
 Not 
 drained. 
 
 Tile- 
 .drained. 
 
 Not 
 drained. 
 
 Tile 
 drained. 
 
 1 
 
 2 
 
 None . . . 
 
 6.4 
 6.7 
 
 1.5 
 3.3 
 
 9.4 
 16.2 
 
 17.2 
 17.2 
 
 6.3 
 6.5 
 
 3.3 
 
 11.5 
 
 Lime 
 
 3 
 
 4 
 5 
 
 Lime nitrogen 
 
 5 9 
 
 2.7 
 6,. 5 
 4.9 
 
 18.1 
 25.9 
 27.5 
 
 20.6 
 27.5 
 
 27.2 
 
 11.0 
 25.0 
 16.2 
 
 9.2 
 28.3 
 14.7 
 
 Lime, phosphorus .... 
 
 13.5 
 11.6 
 
 Lime, potassium 
 
 6 
 
 7 
 8 
 
 Lime, nit., phos 
 
 9.3 
 6.8 
 12.4 
 
 8.0 
 7.3 
 14.1 
 
 25.0 
 23.8 
 30.0 
 
 33.8 
 27.2 
 25.6 
 
 32.7 
 20.2 
 27.5 
 
 31.2 
 23.3 
 32.2 
 
 Lime, nit., potassium .... 
 Lime, phos., potassium . . 
 
 9 
 10 
 
 Lime, nit., phos., potass. 
 Nit., phos., potass.. 
 
 10.4 
 2.0 
 
 10.4 
 
 4.8 
 
 29.1 
 25.6 
 
 31.9 
 33.1 
 
 33.3 
 27.3 
 
 30.5 
 
 28.2 
 
 Average gain for nitrogen 
 Average gain for phosphorus . . . 
 Average gain for potassium. . . . 
 
 -3.0 
 3.9 
 1.4 
 
 .1 
 5.2 
 4.1 
 
 -1.0 
 6.1 
 6.3 
 
 4.1 
 6.7 
 3.1 
 
 5.5 
 16.2 
 5.5 
 
 1.9 
 15.9 
 5.1 
 
 By "average gain" is meant the average of four trials with the 
 elements named. Thus, by comparing the yields of wheat from plots 2 
 and 4 on the tile-drained division in 1904 (last column), it will be seen 
 that the addition of phosphorus increased the yield of wheat from 11.5 
 on plot 2 to 28.3 on plot 4, a gain of 16.8 bushels for the phosphorus 
 applied. Comparing the yields from plots 3 and 6, we see that phos- 
 phorus, added to lime and nitrogen, made a gain of 22 bushels of wheat 
 to the acre. Phosphorus made a gain of 17.5 bushels on plot 8, as com- 
 pared with plot 5, and a gain of 7.2 bushels on plot 9 as compared with 
 plot 7. The total gain from the four tests is 63.5 bushels, or an average 
 gain of 15.9 bushels of wheat per acre, due to the phosphorus applied, 
 as stated' in^the table. 
 
 _ 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 585 
 
 It will be observed that the 1902 corn crop was a failure, 14.1 bushels 
 being the highest yield obtained, and the oat crop in 1903 was also 
 very poor, so that no conclusions can be drawn from the first two years' 
 work, although phosphorus seems to rank first when the average gains 
 made by each of the three elements are compared. 
 
 The 1904 wheat crop was fairly satisfactory, although it was much 
 damaged by rust, especially on the better yielding plots. Phosphorus 
 produced very marked gains in the yield of wheat, averaging 16 bushels 
 gain for eight separate tests. The gain for nitrogen was 3.7 bushels, 
 and for potassium 5.3 bushels, as an average of eight separate tests 
 with each element. The lime-nitrogen treatment on plot 3 corresponds 
 to legume-lime treatment on our rotation experiments, where the legume 
 treatment is depended upon to supply the nitrogen. The growing of 
 legumes (mostly cow peas) with the hope of thus improving this southern 
 Illinois soil is a somewhat common practice, and some ground limestone 
 is already being used to correct the acidity of soil and thus to encourage 
 the nitrogen-gathering bacteria and make the growing of legumes, 
 especially of red clover, more successful. It may be definitely stated, 
 even at this early date, and without hesitation or doubt, that a liberal 
 use of lime and legumes will be an essential part of any practical and 
 economical system that ever becomes successful in the permanent im- 
 provement of southern Illinois soil. This being granted, it is of especial 
 interest and importance to note the marked effect produced by adding 
 phosphorus to lime and nitrogen. By comparing plots 3 and 6, it will 
 be observed that phosphorus produced some gain every year on both 
 undrained and tile-drained land, 3.4 and 5.3 bushels of corn in 1902, 
 6.9 and 13.2 bushels of oats in 1903, and 21.7 and 22 bushels of wheat 
 in 1904, all of which tends to prove that a liberal use of the element 
 phosphorus must be included in the plan for improving this soil, especially 
 for wheat growing. The wheat grower will be interested to know that 
 the quality or market value of the wheat was also markedly improved 
 by phosphorus. According to the grain buyer at DuBois, the wheat 
 from plots 106 and 206 (averaging 32 bushels per acre), was worth 15 
 cents more per bushel than the wheat from plots 103 and 203 (averaging 
 10 bushels per acre). 
 
 Clover was seeded with the oats on the DuBois field in 1903, and a 
 very good stand was obtained, but most of it died even before the oats 
 were cut. A careful examination showed that the soil did not contain 
 the red clover bacteria, as no tubercles could be found upon the clover 
 roots. The field was inoculated about the first of July with infected 
 red clover soil, and this may have been some help to the clover still 
 living at that time, and the clover, although a poor stand, doubtless 
 helped the bacteria to multiply somewhat, so that the soil became well 
 infected. The field was plowed and seeded to wheat in the fall of 1903, 
 
586 
 
 BULLETIN No. 99 
 
 | March, 
 
 PLATE 11. FIRST YEAR CLOVER (MOSTLY FOUL GRASS) WITH No SPECIAL SOIL 
 TREATMENT: DuBois SOIL EXPERIMENT FIELD, 1904 (AUTUMN). 
 
 and clover again seeded in the spring of 1904. A good stand was ob- 
 tained and, with the exception of the unlimed check plots, a very satis- 
 factory growth was made during the season of 1904, and the clover was 
 found to be well provided with root tubercles. On the unlimed check 
 plots most of the clover died during the season. Of course, no clover 
 yields will be obtained till next season, but Plates 11 and 12 show the 
 condition of the clover in the fall of 1904. It will be seen that on the 
 check plot, where no lime was applied, there is only a scanty growth 
 of foul grass and weeds, while a good growth of clover is seen on the 
 limed plot. 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 587 
 
 PLATE 12. FIRST YEAR CLOVER ("KNEE DEEP") WITH LIME TREATMENT: 
 DuBois Son. EXPERIMENT FIELD, 1904 (AUTUMN). 
 
 THE CUTLER FIELD. 
 
 The Cutler Soil Experiment Field is located about five miles north- 
 west of Cutler, Perry County, on the farm of Mr. W. E. Braden. The 
 original field contains 40 fifth-acre plots. Thirty of these are in three 
 divisions of 10 plots each, for a three-year rotation of wheat, corn, and 
 cow peas. On certain plots a catch crop of cow peas is also grown after 
 the wheat and with the corn. The other 10-plot series is used for a 
 "complete fertility test," some nitrogen having been purchased for use 
 on this field. A four-year rotation of corn, oats, wheat, and clover is 
 followed on this series. The soil treatment and crop yields for the 
 individual plots are shown in Tables 6 and 7. None of the Cutler field 
 is tile-drained. 
 
588 
 
 BULLETIN No. 99. 
 
 [March, 
 
 TABLE 6. CROP YIELDS IN SOIL EXPERIMENTS: CUTLER FIELD. 
 
 Soil 
 plot 
 
 No. 
 
 Gray silt loam prairie, 
 Lower Dlinois Glaciation. 
 
 Bushels per acre. 
 
 Soil treatment applied. 
 
 1902. 
 
 1903. 
 
 1904. 
 
 
 Cow Peas. 
 
 Wheat, 
 
 Corn. 
 
 201 
 202 
 203 
 
 None 
 
 removed 
 turned 
 removed 
 
 6.0 
 9.2 
 12.1 
 
 22.8 
 24.7 
 36.9 
 
 Legume . . 
 
 Manure 
 
 204 
 205 
 
 Legume, lime 
 
 turned 
 removed 
 
 13.5 
 13.3 
 
 30.6 
 44.1 
 
 Manure, lim'e 
 
 206 
 207 
 
 Legume, lime, phosphorus 
 
 turned 
 removed 
 
 20.3 
 20.8 
 
 30 6 
 30.9 
 
 Manure, lime, phosphorus 
 
 
 208 
 209 
 210 
 
 Legume, lime, phosphorus, potass. 
 Manure, lime, phosphorus, potass. 
 Lime, phosphorus, potass. 
 
 turned 
 removed 
 removed 
 
 26.8 
 24.0 
 21.1 
 
 60.0 
 70.9 
 71.9 
 
 
 Oats. 
 
 Cow Peas. 
 
 Wheat. 
 
 211 
 212 
 213 
 
 None 
 
 19.6 
 23.8 
 26.6 
 
 removed 
 turned 
 removed 
 
 9.0 
 8.5 
 18.2 
 
 Legume . 
 
 Manure 
 
 214 
 215 
 
 Legume, lime 
 
 26.9 
 27.8 
 
 turned 
 removed 
 
 8.8 
 18.4 
 
 Manure, lime 
 
 216 
 217 
 
 Legume, lime, phosphorus 
 
 28.0 
 25.2 
 
 turned 
 removed 
 
 14.3 
 19.7 
 
 Manure, lime, phosphorus 
 
 218 
 219 
 220 
 
 Legume, lime, phosphorus, potass. 
 Manure, lime, phosphorus, potass. 
 Lime, phosphorus, potass. 
 
 31.1 
 
 28.8 
 26.7 
 
 turned 
 removed 
 removed 
 
 16.4 
 19.7 
 15.0 
 
 
 Wheat. 
 
 Corn. 
 
 Cow Peas. 
 
 221 
 222 
 223 
 
 None 
 
 12.8 
 12.4 
 12.4 
 
 4.0 
 3.7 
 3.5 
 
 removed 
 turned 
 removed 
 
 Legume 
 
 Manure 
 
 224 
 225 
 
 Legume, lime 
 
 13.3 
 12.9 
 
 3.7 
 3.6 
 
 turned 
 removed 
 
 Manure, lime 
 
 226 
 227 
 
 Legume, lime '"phosphorus . . 
 
 16.9 
 16.1 
 
 2.4 
 2.1 
 
 turned 
 removed 
 
 Manure, lime, phosphorus 
 
 228 
 229 
 230 
 
 Legume, lime, phosphorus, potass. 
 Manure, lime, phosphorus, potass. 
 Lime, phosphorus, potass. 
 
 20.8 
 19.4 
 20.8 
 
 3.7 
 6.1 
 9.2 
 
 turned 
 removed 
 removed 
 
 Manure is applied for wheat after cow peas. Plots 203, 205, 207 
 and 209 were manured for the 1903 wheat crop, plots 213, 215, 217 and 
 219 for the 1904 wheat crop, and plots 223, 225, 227 and 229 for the 
 1905 wheat crop. Thus, no crop grown in 1902 had received manure 
 or legume treatment. During the first course of the rotation one full 
 crop of cow peas has been turned under on all plots receiving legume 
 treatment, but afterward the legume treatment consists of catch crops 
 only. Lime was not applied to plots 224 to 230 till after the 1902 wheat 
 crop had been harvested. Oats were substituted for corn in 1902 on 
 plots 211 to 220. 
 
1905.] SOIL TREATMENT FOR THE LOWEH ILLINOIS GLACIATION. 589 
 
 In 1902 phosphorus increased the yield of wheat from 12.8 (average 
 of five untreated plots), to 16.5, a gain of 3.7 bushels, and potassium 
 further increased the yield from 16.5 to 20.3, a gain of 3.8 bushels, but 
 no appreciable effect was produced on the oat crop. 
 
 In 1903 the corn crop was a failure on the Cutler field, owing to 
 the drouth. On the other hand, some very satisfactory results were 
 obtained with wheat, the maximum increase being from 6 bushels, with 
 no treatment, to 26.8 bushels, with legume-lime-phosphorus-potassium 
 treatment, a gain of 20.8 bushels of wheat, the credit for this increase 
 being divided as follows: 3.2 for legume treatment, 4.3 for lime, 6.8 
 for phosphorus, and 6.5 for potassium. With the manured plots the total 
 gain was 18 bushels, divided as follows: 6.1 for manure alone, 1.2 for 
 lime, 7.5 for phosphorus, and 3.2 for potassium. Lime-phosphorus- 
 potassium treatment made a gain of 15.1 bushels, without manure or 
 legume turned under. 
 
 In 1904 the wheat was much injured by rust, especially on the best 
 treated plots. Manure alone made a gain of 8.4 bushels. Phosphorus 
 gained 5.5 bushels on the legume plot. These are the most marked 
 effects from the treatment, but no conclusions can be drawn, owing to 
 the great damage from rust, which probably reduced the yield fully 
 one-half on some plots. The corn crop, however, was fairly satisfactory. 
 The manure applied in 1902 still shows some effect in 1904, although 
 the results are discordant. The most marked and positive result is 
 the large increase produced by potassium, the average increase being 
 from 30.8 to 67.6, or a gain of 36.8 bushels of corn per acre for the element 
 potassium. On the undrained land at Odin potassium gained 22.5 
 bushels of corn, and on the undrained land at Edgewood potassium 
 gained 8.5 bushels. An average of these three tests in 1904 makes a 
 gain of 22.6 bushels of corn to the acre for this element potassium. At 
 40 cents a bushel, this corn would be worth $9.04. The potassium 
 applied to these fields during the past three years amounts to 160 pounds 
 of that element. At 6 cents a pound, this has cost $9.60 an acre. With 
 one exception, small gains were made by potassium on all of these fields 
 in 1902 and 1903, so that the increased crop yields have fully paid for 
 all the potassium which has been used on those plots which grew corn 
 in 1904, but this is not true with plots which did not grow corn in 1904, 
 and which have also received potassium. Consequently, it is still an 
 open question whether the purchase of commercial potassium for use 
 on this soil will be profitable. By studying the plant food taken from 
 the soil by different crops, as given on page 4 of Circular 68, also the 
 yield of crops from these different fields, as reported in this bulletin, 
 it will be seen that about one-half of the potassium which has been 
 applied to these fields still remains in the soil, so that the soil is growing 
 richer instead of poorer, It should also be remembered that it takes 
 
590 
 
 BULLETIN No. 99. 
 
 some time to get the full benefit of soil treatment, especially of rotation 
 of crops. We cannot practice a four-year rotation in one year's time. 
 Indeed, it really takes four years to get such a rotation properly started. 
 The second four-years' course should show some of the benefits, but the 
 full benefits should not be expected before the third four-years' course. 
 It is true that the effect of potassium on the 1904 corn crop was 
 extremely marked, but it is also true that the season of 1904 was ex- 
 tremely abnormal in southern Illinois. During most of the growing 
 season the frequent and heavy rains kept the ground soaked so full of 
 water that the feeding range of the plant roots was limited to a few 
 inches of surface soil. It is conceivable that a liberal supply of readily 
 available potassium in these few inches of soil would be of tremendous 
 advantage to the plant under such conditions, a good supply of the other 
 plant food elements also being provided, as was the fact in all cases. 
 This much we know with certainty from the chemical analysis of this 
 soil, namely, that it actually contains moderate amounts of potassium 
 in the surface, and large amounts of potassium in the subsoil, and these 
 investigations must be continued until we learn definitely whether we 
 cannot draw potassium from that immense store more cheaply than we 
 can obtain it from the mines of Germany. Decaying organic matter, 
 such as farm manure and green manures, will help to liberate potassium 
 from the soil. Deep rooting plants, especially biennial plants like red 
 clover, and perennial plants like alsike clover, which have strong feeding 
 powers, will help to obtain potassium from the soil and to bring it up 
 from the subsoil, and we already have some evidence that tile drainage 
 will help to make the potassium in the subsoil more available. 
 
 TABLE 7. CROP YIELDS IN SOIL EXPERIMENTS: CUTLER FIELD. 
 
 Soil 
 plot 
 
 No. 
 
 Gray silt loam prairie, 
 Lower Illinois Glaciation. 
 
 Bushels per acre. 
 
 Soil treatment applied. 
 
 1902 
 Corn. 
 
 1903 
 Oats. 
 
 1904 
 Wheat. 
 
 1 
 2 
 
 None 
 
 6.8 
 5.2 
 
 15.2 
 13.7 
 
 9.0 
 10.5 
 
 Lime 
 
 3 
 
 4 
 5 
 
 Lime, nitrogen 
 Lime, phosphorus 
 Lime, potassium 
 
 1.2 
 3.5 
 2.9 
 
 16.6 
 14.2 
 18.0 
 
 9.8 
 21.9 
 10.0 
 
 6 
 
 7 
 8 
 
 Lime, nitrogen, phosphorus 
 Lime, nitrogen, potassium 
 Lime, phosphorus, potassium . . . 
 
 2.2 
 2.8 
 10.2 
 
 20.3 
 20.0 
 27.5 
 
 15.8 
 8.2 
 22.4 
 
 9 
 10 
 
 Lime, nitrogen, phosphorus, potas. 
 Nitrogen, phosphorus, potas. 
 
 4.6 
 5.4 
 
 28.7 
 37.7 
 
 17.7 
 15.0 
 
 Average gain for nitrogen 
 Average gain for phosphorus 
 Average gain for potassium 
 
 2.8 
 + 2.1 
 
 + 2.4 
 
 + 5.0 
 
 + 5.6 
 + 7.4 
 
 4.9 
 + 9.8 
 + .1 
 
Son. TKKATMKNT KOH THU LOWKK ILLINOIS GLACIATION. 591 
 
 Tlic other division of the field at Cutler contains 10 plots in the 
 "complete fertility test." A four-year rotation of corn, oats, wheat, 
 and clover is being grown upon this field. The treatment applied and 
 the crop yields obtained are shown in Table 7. 
 
 The corn crop grown in 1902 was almost a complete failure, chiefly 
 because of the drouth, although some damage was caused by chinch 
 bugs, 10.2 bushels per acre being the highest yield. 
 
 In 1903 a light crop of oats was produced. Appreciable gains were 
 made by applications of plant food, especially by phosphorus and potas- 
 sium combined. The lime applied in 1902 was found to be insufficient 
 to correct the acidity of the soil, and a heavier application was made 
 for 1903. There is some evidence that the effect of this was to reduce 
 the yield of oats, and this might be expected, especially where phos- 
 phorus has been applied. Similar effects have been observed at times 
 in pot-culture experiments, but the injurious effect is temporary and 
 really emphasizes the importance of applying lime some months before 
 the crop is to be grown, or of plowing under the phosphorus and then 
 applying the lime to the plowed soil, the effect of lime in intimate con- 
 tact with phosphorus being to hold the phosphorus in an insoluble form. 
 We already have conclusive evidence that heavy applications of some 
 form of lime must be used on this soil for the successful growing of legume 
 crops, especially the clovers and alfalfa, and certainly we can never hope 
 to restore and profitably maintain the fertility of this soil without 
 legumes. 
 
 In 1904 the best wheat plots were much injured by rust, on this 
 part of the Cutler field, as well as on tHe other. The only noteworthy 
 result of soil treatment is the marked effect produced by the element 
 phosphorus. As an average of four separate trials, phosphorus made 
 a gain of 9.8 bushels of wheat. 
 
 GENERAL AVERAGE INCREASE. 
 
 While the data obtained from these three years' work do not justify us 
 in drawing final conclusions, yet it seems worth while to make some gen- 
 eral averages of the effects produced by each of the three plant food ele- 
 ments, bearing in mind as we consider them, that the first two years were 
 seasons of severe drouth, especially for corn at Odin, DuBois, and Cutler, 
 and that the last year (1904) until midsummer, was one of the wettest 
 seasons ever known in southern Illinois. 
 
 Table 8 shows the average increase in bushels of corn, oats, and wheat 
 produced by nitrogen, phosphorus and potassium, the total number of 
 separate tests or trials being mentioned in each case. 
 
 Every individual test which has been made on this type of soil and 
 reported in the preceding pages to determine the effect of each of these 
 three elements, either alone or in combination, is represented in the 
 averages {riven in Table K, 
 
592 
 
 BULLETIN No. 99. 
 
 [March, 
 
 TABLE 8. INCREASE IN CROP YIELDS IN SOIL EXPERIMENTS, AVERAGE TESTS ON 
 
 ALL FIELDS ON GRAY SILT LOAM PRAIRIE SOIL OF THE LOWER 
 
 ILLINOIS GLACIATION. 
 
 Soil treatment 
 
 Corn. 
 
 Oats. 
 
 Wheat. 
 
 Average 
 
 Total 
 
 applied. 
 
 Bu. in- 
 
 No. of 
 
 Bu. in- 
 
 No. of 
 
 Bu. in- 
 
 No. of 
 
 value of 
 increase. 
 
 number 
 of tests. 
 
 
 crease. 
 
 tests. 
 
 crease. 
 
 tests. 
 
 crease. 
 
 tests. 
 
 
 
 Nitrogen .... 
 
 3.5 
 
 16 
 
 + 1.2 
 
 16 
 
 + 1.4 
 
 12 
 
 SO. 02 
 
 44 
 
 Phosphorus . . 
 
 + 1.8 
 
 32 
 
 + 5.3 
 
 25 
 
 + 11.2 
 
 21 
 
 3.27 
 
 78 
 
 Potassium . . . 
 
 + 5.3 
 
 32 
 
 + 4.2 
 
 25 
 
 + 3.6 
 
 21 
 
 1.81 
 
 78 
 
 It will be seen that the average yield of corn has been reduced 3.5 
 bushels by nitrogen, increased 1.8 bushels by phosphorus, and in- 
 creased 5.3 bushels by potassium. 
 
 The average- yield of oats has been increased 1.2 bushels by nitrogen, 
 5.3 bushels by phosphorus, and 4.2 bushels by potassium. 
 
 The average yield of wheat has been increased 1.4 bushels by nitrogen, 
 11.2 bushels by phosphorus, and 3.6 bushels by potassium. 
 
 If we consider corn worth 35 cents a bushel, oats 25 cents a bushel, and 
 wheat 70 cents a bushel, then the average value of the increase produced 
 by nitrogen is 2 cents an acre a year, as an average of the three crops in- 
 cluding 44 separate tests; the average value of the increase produced by 
 phosphorus is $3.27 an acre a year, including 78 separate tests; and $1-.81 
 an acre a year is the average value of the increase produced by potassium, 
 78 separate tests being included. 
 
 The present retail price of good steamed bone meal in southern Illinois, 
 containing 12 percent of phosphorus, is about $25 a ton. At this rate 
 25 pounds of phosphorus or 2 pounds more than would be removed in a 
 100-bushel crop of corn, would cost $2.50. 
 
 At $50 a ton for potassium chlorid (the cheapest commercial form of 
 potassium) which contains about 42 percent of that element, the 71 
 pounds of potassium removed in a 100-bushel crop of corn would cost 
 about $4.20. 
 
 At the same prices the 11 pounds of phosphorus removed by a 75-bushel 
 crop of oats would cost $1.10, and the 49 pounds of potassium for the 
 same crop would cost $2.94; the 12^ pounds of phosphorus for a 50- 
 bushel wheat crop would cost $1.25, and the 56 pounds of potassium 
 required for the same crop would cost $3.36. 
 
 It will thus be seen that if we consider the plant food requirements 
 of these crops and the present prices of phosphorus and potassium and the 
 increased crop yields which those elements have produced as an average 
 of 78 tests each, we can very profitably make use of phosphorus in steamed 
 bone meal in sufficient quantities to maintain such maximum crop yields, 
 but it is not so evident that commercial potassium can be used with profit. 
 
 Raw rock phosphate containing 250 pounds of phosphorus to the ton 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 593 
 
 is as rich as good steamed bone meal and can be obtained in carload lots 
 delivered at any railroad station in southern Illinois for about $8.00 a 
 ton, or one-third the price of steamed bone meal. When used in combina- 
 tion with decaying organic matter, raw rock phosphate promises to be 
 the most economical form of phosphorus to purchase and use on this soil. 
 
 THE CIRCULATION OF PLANT FOOD. 
 
 From two-thirds to three-fourths of the phosphorus removed in the 
 above-named crops is contained in the grain, while only one-fourth to 
 one-third is contained in the stover or straw. If the grain is sold, the 
 larger part of the phosphorus is sold with it. If the crops are fed to 
 growing animals, about 20 to 30 percent of the phosphorus is used in the 
 formation of bones, and these are sold with the animals. That the element 
 phosphorus is already deficient in this soil has been shown by chemical 
 analysis and confirmed by pot cultures and by many field experiments 
 each year for three successive years, and there is no system of farming 
 which can be followed by all farmers which does not continually remove 
 phosphorus from the farm. (Butter is the only common farm product 
 which contains no appreciable amount of phosphorus.) 
 
 Regarding potassium there are some interesting points to be consid- 
 ered. The chemical composition of this soil shows that it is moderately 
 well supplied with that element, even in the top soil, and that the sub- 
 soil is rich in potassium. Whether sufficient potassium for the most 
 profitable crop yields can be liberated from the soil by the use of decay- 
 ing organic matter, deep rooting crops, tile drainage, etc., is not yet 
 determined. (Some extensive experiments with subsoiling are included 
 in plans for continuing the investigation of this soil type.) 
 
 About three-fourths of the potassium removed from the soil by crops 
 of corn, oats, or wheat is contained in the stalks or straw, while only one- 
 fourth is contained in the grain. If the crops are fed on the farm, prac- 
 tically all of the potassium remains in the solid and liquid manure, and 
 it may thus be returned to the land. Because of these facts, it thus be- 
 comes possible to use potassium again and again if we practice a live stock 
 system of farming and carefully save and return to the land all of the 
 farm manure. Even if we sell some of the most valuable grains, such as 
 wheat, but feed the corn and oats and all coarse feed, using sufficient bed- 
 ding to absorb and retain all liquid manure, we would still lose but very 
 little potassium from the farm. This being true, it may ultimately prove 
 profitable to maintain in the soil a liberal supply of available potassium, 
 even though it may be necessary to make heavy initial applications of 
 commercial potassium, and afterward to restore from time to time as 
 much as is sold or lost from the farm, but further investigations are 
 needed to determine this. 
 
594 BULLETIN No. 99 
 
 It is good farm practice to remove large quantities of plant food from 
 the soil, for the simple reason that large crops require large quantities 
 of plant food ; but it is no less important to restore to the soil when needed 
 as large or larger quantities of plant food as are removed by turning 
 under catch crops and crop residues not removed from the field, by re- 
 turning manures produced on the farm, and so far as necessary by the 
 purchase of commercial plant food, such as phosphorus in bone meal or 
 rock phosphate, or potassium in potassium chlorid or potassium sulfate. 
 Thus the most important process in all farm operations is the circulation 
 of plant food, without which the fertility of cropped soils cannot be per- 
 manently maintained. 
 
 RECOMMENDATIONS CONCERNING SOIL TREATMENT FOR 
 
 THE LOWER ILLINOIS GLACIATION. 
 
 FARM MANURE. 
 
 So far as possible all general farm crops, excepting the most valuable 
 grains, should be fed to live stock. Plenty of bedding should be used and 
 all solid and liquid manure thus saved and returned to the land. A live 
 stock system of farming is very much more important for this soil at 
 the present time than for the richer soils of the corn belt. 
 
 It is scarcely necessary to dwell upon the great value of farm manure 
 for use on this soil. Indeed, the farmers of southern Illinois commonly 
 appreciate the value of farm manure much more fully than do the farmers 
 in the central and northern parts of the state. As a rule, the farm man- 
 ure produced in southern Illinois is carefully saved and used, and the 
 only insurmountable difficulty of restoring all the soil of the Lower 
 Illinois Glaciation to a high state of fertility by the use of farm manure is 
 the simple fact that all the manure now being produced in southern Illinois 
 is barely sufficient to manure the garden patches. The crops grown 
 on that soil without the use of imported plant food, even though they 
 were all fed to live stock, would never produce sufficient manure to make 
 that land rich. 
 
 LEGUMES AND LIME. 
 
 While it is true that nitrogen is not the element which first limits 
 the yield of crops upon this soil, it is also true that the fertility of the 
 soil cannot be satisfactorily increased and permanently maintained 
 without some provision of maintaining the supply of nitrogen. The 
 most economical and rational method of restoring and maintaining the 
 supply of nitrogen is by means of legume crops, and legumes should cer- 
 tainly be given a prominent place in any system of crop rotation adopted 
 on this land. But clover and other valuable legume crops cannot be 
 grown in strongly acid soils with full success owing to the fact that the ni- 
 trogen-fixing bacteria are-not sufficiently active and effective in such soils. 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 595 
 
 As a result of chemical analysis and of the field experiments thus far per- 
 formed, it is recommended that at least two tons per acre of ground lime- 
 stone be applied to this soil previous to sowing legumes. For the best 
 results, it is believed that this should not be plowed under, but rather 
 applied after plowing and mixed with the surface soil by disking, harrow- 
 ing, and cultivating. If applied after the soil is plowed for corn, the 
 limestone becomes thoroughly mixed with the soil by the time the corn is 
 laid by. The corn may be followed by cow peas or soy beans or by wheat 
 or oats and the land then seeded to clover. 
 
 Unless it is known that the soil is already infected with the proper 
 nitrogen-fixing bacteria, it should of course be inoculated. The surest 
 and simplest method of inoculation for clover is to obtain some thorough- 
 ly infected soil from an old clover field wherever tubercles are found in 
 abundance on the clover roots. In most vicinities, some good patches of 
 clover can be found within hauling distance on some old feed lot or patch 
 of timber land or bottom land. About 100 pounds to the acre of thor- 
 oughly infected soil scattered over the land broadcast about the time the 
 clover is seeded will usually produce a satisfactory inoculation if the 
 soil is in suitable condition, although several hundred pounds may well 
 be used if the expense is slight. Farmers are strongly advised against 
 buying any patent artificial bacteria cultures with which to make inocu- 
 lating solutions. Artificial cultures have been used in comparison with 
 the natural soil method for about fifteen years, but the combined evidence 
 of all comparable data thus far reported is strongly in favor of using the 
 natural soil method. Ten years ago German promoters established com- 
 mercial laboratories and endeavored to sell artificial cultures of nitrogen- 
 fixing bacteria to the farmers. Just now American promoters are trying 
 to sell artificial cultures to American farmers. One 1905 Seed Catalogue 
 advertises as follows: 
 
 "NITRO-CULTURE. 
 
 "A Wonderful Discovery. 
 
 "Doubles the Yield. 
 
 "Insures Crops of Alfalfa and other Leguminous Plants on all Soils. 
 
 "Price, postpaid, pkg., sufficient for one acre, $2.00." 
 
 While it is true that the inoculation of legumes on suitable soils, not 
 already infected with the proper bacteria, usually results in a marked 
 increase in yield, it is also true that this "wonderful discovery" was made 
 some fifteen years ago. It is not true that the mere inoculation of the 
 soil "insures crops of alfalfa and other leguminous plants on all soils," 
 as lime and phosphorus (and on some soils potassium) are just as es- 
 sential as nitrogen-fixing bacteria. It is tine that inoculation can be 
 
596 BULLETIN No. 99. [March. 
 
 produced by the use of such artificial cultures with sufficient care and 
 proper manipulation, but it is also true that the surest and simplest 
 method is to use natural soil, and usually this is the least expensive in the 
 end, unless the infected soil must be shipped long distances. For further 
 information relating to this subject, the reader is referred to Illinois 
 Bulletin No. 76, "Alfalfa on Illinois Soils," and No. 94, "Nitrogen Bac- 
 teria and Legumes," and to Circular No. 86, "Science and Sense in the 
 Inoculation of Legumes." 
 
 PHOSPHORUS. 
 
 It is true that we can increase the supply of nitrogen (the element 
 needed least of all) by the use of legumes; and possibly, by means of 
 decaying organic matter, by tile drainage, or by subsoiling, or by two 
 or three of these methods, we can make available from the soil sufficient 
 potassium for maximum profitable crop yields, and by feeding practically 
 all of the crops and saving and returning to the soil all of the manure, we 
 can perhaps maintain the supply of potassium indefinitely; but there is 
 no method known or suggested by which the ordinary soil of the Lower Illinois 
 Glaciation can be made sufficiently rich in phosphorus to produce the most 
 profitable crops without buying phosphorus in some form and applying it to 
 the land. 
 
 The average results of all experiments show that the increased crop 
 yields produced by phosphorus are more than enough to pay for steamed 
 bone meal sufficient to meet the needs of maximum crop yields, so that by 
 proper use of steamed bone meal, the soil could be steadily enriched in 
 phosphorus and yield an increased net profit at the same time. And it 
 now seems evident that by proper use of large amounts of raw rock phos- 
 phate with decaying organic matter, the soil can be more rapidly enriched 
 in phosphorus at less expense and with greater increase in net profits than 
 with steamed bone meal s 
 
 The method of applying the rock phosphate may vary under dif- 
 ferent conditions. It may be sprinkled over the manure from day to day 
 as it accumulates in the stable or feeding shed, at the rate of about 100 
 pounds of rock phosphate for each ton of manure ; or it may be sprinkled 
 over the manure as it is being loaded on the wagon or manure spreader ; or 
 it may be spread broadcast on the land and plowed under with stable 
 manure or clover or cow peas, or other organic matter. If the ground 
 could be disked before being plowed, and the phosphate and organic 
 matter thus mixed with each other and with the soil, it would doubtless 
 be an advantage. 
 
 There is no doubt that it is best to plow the phosphate under, but 
 it is believed that the ground limestone which may be used on a'cid soils 
 should not be plowed under, but rather applied after plowing and well 
 mixed with the surface soil. 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 597 
 
 CROPS AND CROP ROTATIONS. 
 
 While any of the ordinary farm crops can be grown successfully on 
 the soil of the Lower Illinois Glaciation, as shown by the fact that our best 
 treated plots in 1904 produced higher yields than 60 bushels of corn, 40 
 bushels of oats, 30 bushels of wheat, and 2 tons of clover hay, nevertheless 
 the soil is better adapted to some crops than to others. Undoubtedly 
 wheat takes first rank among the crops well adapted to this soil and 
 climate. The compact soil is very suitable for wheat culture. The fall 
 weather is usually favorable to sowing wheat and the mild winter and 
 early spring with abundant rainfall make almost ideal weather conditions 
 for this crop. Furthermore, the wheat usually matures soon after the 
 heavy spring rains and before the midsummer drouth. The nearness 
 to the great wheat markets is an additional advantage. 
 
 The chief difficulties in wheat growing are the lack of proper plant 
 food, the Hessian fly, the chinch bug, and the tendency of the farmer 
 to grow wheat after wheat. By suitable rotation of crops, the development 
 of the fly and chinch bugs is discouraged, and by rotation and proper 
 treatment, the soil becomes able to produce strong growing plants which 
 suffer less from insect attacks. Land bearing a heavy crop of wheat, es- 
 pecially with a good growth of clover in it, offers very unfavorable condi- 
 tions for the chinch bug. 
 
 The oat crop is not well adapted to this soil and climate. Chiefly 
 because the land is not well drained, the frequent early spring rains 
 render it difficult to sow oats at the proper time, and the early summer 
 drouth may injure the immature crop. 
 
 Unless the summer drouth is too severe, corn, cow peas, soy beans, and 
 clover are very well adapted to this soil when properly treated. 
 
 The soil and climate are w r ell adapted to the growing of timothy and 
 recltop, but neither of these crops should be grown and sold from the farm 
 as hay, except at very high prices, sufficient to cover the cost of the plant 
 food removed and leave a profit. 
 
 The following rotations are suggested for consideration : 
 
 THREE- YEAR ROTATION. 
 
 First Year Wheat, followed by cow peas or soy beans as catch crop. 
 
 Second Year Corn, with cow peas or soy beans as catch crop. 
 
 Third Year Cow peas or soy beans (to be followed by wheat). 
 
 Every three years, about 500 pounds of steamed bone meal should be 
 applied for the wheat or 1,000 pounds of raw rock phosphate may be 
 spread on the catch crop after wheat (preferably with farm manure) 
 and plowed under for corn. As an initial application, 2 tons of ground 
 limestone should be applied after the ground is plowed for corn, further 
 applications to be applied as needed to keep the soil sweet, perhaps 1 
 
598 BULLETIN No. 99. 
 
 ton every six years. All crops except the wheat should be fed or pastured 
 or used as bedding and all manure returned to the land. If the com crop 
 is cut and shocked, then a three-year rotation of corn, wheat, and clover 
 is a good one. 
 
 FOUR- YEAR ROTATION. 
 
 First Year Corn, with cow peas or soy beans as catch crop. 
 
 Second Year Cow peas or soy beans. 
 
 Third Year Wheat (with clover to be seeded in spring). 
 
 Fourth Year Clover. 
 
 If well filled the second crop of clover should be harvested for seed. 
 All other crops excepting wheat and possibly cow pea or soy bean seed 
 should be fed and the manure returned to the land, preferably mixed 
 with about 1,500 pounds of rock phosphate and applied to the clover sod 
 to be plowed under for corn. 
 
 FIVE-YEAR ROTATION. 
 
 This may be the same as the four-year rotation except that timothy 
 may be seeded with clover and the land pastured the fifth year. 
 
 Six- YEAR ROTATION. 
 
 This may be the same as above except that the land is pastured for 
 two years. In this case some alsike should be seeded with the red clover 
 and timothy, as the red clover is only a two-year plant (biennial) while 
 alsike is a short perennial. About one ton per acre of ground rock phos- 
 phate should be applied with the manure to the pasture land to be plowed 
 under for corn every six years, ground limestone to be applied after plow- 
 ing as indicated above. 
 
 Whatever rotation is adopted, there should be as many fields (of 
 approximately equal size) as there are years in the rotation, so that 
 every crop can be grown every year. Where conditions will permit, we 
 prefer the five-year or six-year rotation. It will be observed that a 
 legume crop is provided for every year in every rotation suggested. If 
 the cow peas or soy beans are cultivated and kept clean, the wheat may be 
 seeded on the ground without plowing, in which case, the land is plowed 
 only twice in four, five, or six years. 
 
 While cow pea seed and soy bean seed are valuable to sell for seed, 
 they also have a very high feeding value, being very rich in protein and 
 well suited to balance the carbohydrates in corn. As a rule the soil 
 should be inoculated for soy beans. (See Bulletin Xo. 94.) 
 
 The comparative value of clover can be easily understood from the 
 simple fact that when we were seeding cow peas and soy beans for the 
 1904 crop, we were at the same time cutting two tons per acre of red 
 
1905.] SOIL TREATMENT FOR THE LOWER ILLINOIS GLACIATION. 599 
 
 clover hay as the first crop for 1904. It is not advised to discard the cow 
 pea and soy bean, but it is advised to include clover to some extent at 
 least in the crop rotation for the Lower Illinois Glaciation ; not only be- 
 cause it grows from early spring till late autumn, and lives two years from 
 one seeding, but because it roots deeply, markedly increases the power 
 of the soil to absorb and retain moisture, obtains and liberates plant food 
 present in the soil or subsoil or supplied in low grade materials, gathers 
 nitrogen from the air, and leaves in the soil a large amount of roots rich 
 in plant food elements. 
 
 NOTES. Ground limestone can be obtained from the Crystal Carbonate Lime 
 Company, Elsberry, Mo., or from the Mitchell Lime Company, Mitchell, Ind., for 
 about $2.50 a ton, delivered in Illinois in carload lots, on direct east and west lines 
 running into East St. Louis; on north and south lines it may cost 20 to 30 cents 
 more. Illinois has abundance of good limestone, especially along the Mississippi 
 and in the Ozark hills in the southern part of the state, and it is hoped that grinding 
 plants will soon be established in Illinois so that ground limestone can be obtained 
 more cheaply. It ought to be furnished at any point delivered in carload lots at a 
 total cost of $2.00 a ton or less. 
 
 Finely ground raw rock phosphate (12 percent phosphorus) can be obtained 
 from Robin Jones, Nashville, Tenn., or from the N. Y. & St. L. Mining & Mfg. Co., 
 St. Louis, Mo., for about $8.00 a ton delivered in southern Illinois in carload lots. 
 
 A good grade of steamed bone meal (about 12^ percent phosphorus) can be 
 obtained delivered in southern Illinois for about $25.00 a ton, from the local agents 
 of Armour & Company, Morris & Company, Swift & Company, or others, of the 
 Union Stock Yards, Chicago, 111., and potassium chlorid (42 percent potassium) 
 can also be obtained from Armour & Company, for about $50.00 a ton, f. o. b. cars 
 Chicago. 
 
 The Experiment Station does not analyze miscellaneous samples of soil or 
 other materials for private parties. For methods employed in the investigation 
 of Illinois soils, see Circular No. 68, or Bulletin No. 93, pages 302-3. 
 
UNIVERSITY OF ILLINOIS-URBANA