EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE, 35 
TABLE XI.—Average of results of nine years’ work on three series of plots at 
Galesburg, Ill.—Six-year rotation employed, consisting of corn, corn, oats, 
wheat, clover, and twnothy. 
Average yield per acre. 
Treatment. 
Corn, Oats, Wheat, | Clover, |Timothy, 
9 years. | 5years. | 5years. | 4 years. | 4 years. 
Bushels. | Bushels. | Bushels. Tons. Tons. 
TAB OOYS, < ecetos S e eee CLN, i TaN a 65. 66 48. 24 27.98 ilo 7) 1. 81 
HVESIGUICSMLI Garris Cina ce Meme eon cio iisis nom mals 70. 16 47.08 31.16 1.63 21.43 
IMIG TOIT) lin a2 5 eee ere Race ee et ae ee een ert UE PAL 48. 34 29. 54 2.19 1. 90 
Covercrap manure ]iMes 5-5 dc cco es oee bec eos ceocee 76. 68 50. 20 31. 06 1.90 1.96 
ITO Sb o6 oo ae Ee ee OREO SOG aa ee anaes 71. 64 49. 50 30. 66 2.03 1. 96 
Mime Mbosphatrerocks eos t~ osennintsnn se ceseneecacc 78.57 54. 64 34. 66 2. 40 2.18 
Residu uesmlime: phosphatemock=-. = asscseeeeeeene ne. 79.68 50. 76 35. 22 1,90 21.50 
Manure, lime, p OSHA tenOC kee ee sect ee ceaaisiia tol 81.38 56. 80 33. 30 2.41 2.11 
Cover crop, manure, lime, phosphate rock........... 82. 93 53. 56 35. 32 OES PPA 
PIE TTA ays meets ama, 2 SS kid ele A 8 73.01 47, 28 28. 92 1.81 2.05 
Lime, phosphate rock, potash. ...........5........--. 80. 89 53. 48 34. 46 2. 53 2. 58 
Residues, lime, phosphate rock, potash.............- 81. 68 52.72 34. 74 11.40 21.87 
Manure, lime, phosphate rock, potash. .............. 81. 37 56. 36 32. 46 2.77 2. 
Cover crop, manure, lime, phosphate rock, potash... 83. 94 55. 50 33.96 2.73 2. 26 
ELMO ee pee e ms =e in Sc cussch Gace cote ganged 74. 23 49. 60 27.90 1. 82 2.10 
IRGSIGIDYES 5 = Sasa s sop Ge SE CODONCO OTE Eee se Cesc maees 72.32 49. 42 28. 82 1,82 21.67 
iResiduesiphosphate TOCks ase ance cee cece ccnic sec sudo. 76. 21 51. 62 33. 78 1.85 21.80 
Residues, phosphate rock, potash..............--.... 78.38 48. 44 36. 46 11,51 22.33 
Residues, lime, nitrogen, phosphate rock, potash. . 81. 59 56. 18 35. 95 11.21 22.83 
INGOT CH ryfesterastvatero stertwerers serenade oe ees ise we se gees ces 70. 82 51. 98 29. 04 1.55 2.08 
1 One crop only. 2 Average of three crops. 
While the results given in Table XI are favorable to the use of 
raw rock phosphate they are not tabulated in a manner which brings 
out the true effect of this material. Manure was applied only after 
the experiment had been under way for four years, and the residue 
(or grain farming) system also was not fully in operation for some 
years. The average yields of the plots on which “manure” and 
“residues” were apparently applied therefore include the results 
of years in which no organic matter was used. 
For more detailed figures on this experiment the reader is referred 
to Soil Report No. 7. 
Later this year (1913) the same authors’ published the results 
obtained with raw rock phosphate in two complete rotations (nine 
years) on the Fairfield experiment field, Wayne County, Ill. The 
soil of this experiment field is the common upland type of southern 
Hhnois, consisting of a gray silt loam on dense clay. The history of 
the field is not given. 
The experiment field was divided into four tracts of 10 acres each, 
“one half of the field, or 20 acres, is tile drained while the other half 
has only the ordinary surface drainage. On both the tiled and un- 
tiled land grain farming is practiced on one half and live-stock farm- 
ing on the other half. A part of each of these divisions is treated 
with 2 tons of limestone and 1 ton of ground phosphate rock per acre 
every four years.” No other commercial fertilizers were used. A 
four-year rotation was practiced on this field, consisting of corn, 
soy beans, wheat, and clover, each crop being grown every year on 
y 1Jll. Agr. Expt. Sta.. Soil Rept. No. 8 (1913). 
