230 SOILS AND FERTILIZERS 



Average Yield of Wheat per Acre. 



Bushels. 



No manure for 40 years 14 



Minerals alone for 32 years 15^ 



Nitrogen " " " " 23$ 



Farmyard manure for 32 years 32I 



Minerals and nitrogen for 32 years 1 36^ 



< i (< (( l( <« S ,,3 



3^1 



The food requirements of wheat are such that it should 

 be given a favored position in the rotation. Wheat may 

 follow clover provided the clover sod is light and is 

 fall plowed. On some soils, however, wheat does not 

 thrive following a sod crop. It takes nearly a year 

 for a heavy sod residue to get into suitable food forms 

 for a wheat crop. Under such conditions, oats should 

 first be sown, then wheat may follow. On average 

 soil a medium clover sod, plowed late in summer or in 

 early fall, and followed with surface cultivation, leaves 

 the land in good condition for spring wheat. It is not 

 advisable to have wheat follow barley, because the 

 soil will be too porous, and barley being a stronger 

 feeding crop leaves the land in poor condition as to 

 available plant food. When a corn crop is well ma- 

 nured, wheat may follow. The food requirements of 

 wheat are best satisfied following a light, well cultiva- 

 ted clover sod, or following oats which have been grown 

 on heavy sod, or following corn that has been well 

 manured. 



1 86 pounds of nitrogen as sodium nitrate. 



2 86 " " " " ammonium salts. 



