616 SOILS: PROPERTIES AND MANAGEMENT 



which it is applied. This has proved to be the case with 

 commercial fertilizers, and the fact is also becoming 

 recognized in the economic use of farm manures. 



In general, hay has derived more benefit from the re- 

 sidual food than almost any other crop in the rotation. 

 At the Pennsylvania Experiment Station, 1 in a rotation of 

 corn, wheat, and hay over a test for twenty-five years, in 

 which manure was applied in equal amounts to the corn 

 and wheat, the results were as follows : — 



Percentage Increase from Use of Manure, and Value of 

 that Increase 



The same fact has been clearly shown in the Ohio 

 experiments 2 covering a term of eighteen years. The 

 query immediately arising here is : If hay responds so 

 well to residual feeding, why not apply the manure 

 directly to it? On this point the following figures from 

 the Illinois Experiment Station 3 may be presented, com- 

 paring the response of corn and oats when manured to 

 the yield of clover with the same treatment : — 



1 Hunt, T. F. General Fertilizer Experiments. Ann. Rept. 

 Pennsylvania Agr. Exp. Sta., 1907-1908, pp. 68-93. 



2 Thorne, C. E., and others. Plans and Summary Tables 

 of the Experiments at the Central Farm. Ohio Agr. Exp. Sta., 

 Cir. 120, pp. 101-105. 1912. 



3 Hopkins, C. G. Thirty Years of Crop Rotation in Illinois. 

 111. Agr. Exp. Sta., Bui. 125, p. 337. 1908. 



