SOILS AND FERTILIZERS 



437 



vented by plowing it down in the fall, instead of leaving it exposed 

 on the surface all winter. In order to get some definite data on this 

 point, tests were conducted. It must be remembered that the ma- 

 nure was applied but once in the rotation, and that to the first 

 crop of corn, and that the effects on the wheat was only what re- 

 mained after two crops of corn had already had access to the ma- 

 nure. 



Showing Yields of Corn and Wheat from Plowing Manure Under in 

 Fall and Spring (Yields Per Acre). 



The results given in the above table are slightly, but uniformly, 

 in favor of allowing the manure to remain on top of the land during 

 the winter, and plowing it down in the spring, rather than plowing 

 it down in the fall. This is probably due to the conditions near the 

 surface being more favorable to nitrification, and consequently 

 more of the manure has become available for crops. 



Farmers sometimes object to the spreading of manure in sum- 

 mer, in the belief that when manure is so spread the hot summer 

 suns burn out its substance, as they express it, and make it compara- 

 tively valueless. An inspection of the table shows this belief to be un- 

 founded. The manure spread on July gave better results than that 

 spread in either fall or spring. 



In the following experiment the manure was applied in the win- 

 ter on sod land, and was plowed under at once. On one plot the land 

 was plowed to the usual depth prevailing in that field, or seven inches 

 deep, and the other plot was plowed but five inches deep. The ef- 

 fects of this treatment on the yields of corn and wheat are given 

 in the following table: 



Showing the Results of Plowing Manure Under Different Depths 

 Upon Yields of Corn and Wheat (Yields Per Acre). 



* Average of 4 crops. 



t Average of 2 crops. 



