EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE. 



45 



Table XX. — Average yields of corn, icJieat, and IcgxLmes obtained in a 10-year 

 experiment on three series of plots at Littles, Pike County, Ind. {1906- 

 1915). 



Treatment. 



Average yield per acre. 



Com, 8 crops. 



Ear com. 



Stover, 



"Wheat, 10 crops. 



Grain. 



Straw. 



Legume, 

 3 crops. 



Hay. 



Nothing 



Acid phosphate, 150 pounds i 



Rock phosphate, 1 ton 



Nothing 



Rock phosphate, 1 ton; 2 manure, 10 tons 



Manure, 10 tons 1 



Nothing 



Bushels. 

 41.8 

 41.9 

 39.2 

 37.7 

 46.9 

 47.4 

 41.0 



Pounds. 

 3,298 

 3,288 

 3,030 

 2,990 

 3,435 

 3,698 

 3,427 



Bushels. 

 13.3 

 15.0 

 14.7 

 13.7 

 18.6 

 18.4 

 14.9 



Pounds. 

 1,149 

 1,407 

 1,283 

 1,122 

 1,769 

 1,769 

 1,491 



Pounds. 

 3,987 

 4,353 

 3,913 

 3,767 

 4,930 

 4,043 

 3,793 



1 Per rotation. 



2 Rock phosphate applied at the above rate twice during 10 years. 



Table XXI. — Average yields of corn, wheat, and legumes obtained in a 10-year 

 experiment at Scottsiurg, Scott County, Ind. (1906-1915). 



Treatment. 



Nothing 



Acid phosphate, 150 pounds 1 



Rock phosphate, 1 ton^ 



Nothing 



Rock phosphate, 1 ton; 2 manure, 10 tons 



Manure, 10 tons' ,. 



Nothing i 



Average yield. 



Com, 8 crops. 



Ear com. 



Bushels. 

 25.1 

 34.3 

 40.4 

 30.5 

 51.2 

 50.5 

 30.5 



Stover. 



Pounds, 

 2,366 

 2,817 

 2,988 

 2,578 

 4,114 

 4,025 

 2,583 



Wheat, 10 crops. 



Grain. 



Bushels. 

 9.2 

 15.6 

 13.9 

 10.2 

 20.8 

 20.0 

 10.4 



Straw. 



Pounds. 



862 

 1,392 

 1,311 



992 

 2,138 

 2,073 

 1,061 



Legume, 

 3 crops. 



Hay. 



PouTids. 

 749 

 1,412 

 1,396 

 1,291 

 3,151 

 3,065 

 1,523 



' Per rotation. 



2 Rock phosphate applied at the above rate twice during 10 years. 



The average results of 10 years' work on the Littles field are not 

 very satisfactory, since the difference between the average yields of 

 certain check plots is greater than the difference between the checks 

 and the plots treated with phosphates. Moreover the yields of all 

 crops (except the legumes) on some of the checks were practically ^as 

 good and in some cases better than the yields on the plots treated with 

 phosphates alone, indicating that the soil was not very responsive to 

 phosphate treatments. Only in the case of the legume hay did acid 

 phosphate seem. appreciably more beneficial than raw rock; in fact, 

 it was on this crop only that the former appeared at all effective. 

 More significant increases in the yields of legumes were obtained, 

 however, on plots receiving manure reenforced with phosphate rock. 



On the Scottsburg field the effect of phosphate treatments seemed 

 much more marked, the average yields of the fertilized plots being 



