CBOP ROTATION 27 



together with good cultivation and tile drainage can do 

 towards keeping up soil fertility and maintaining satis- 

 factory crop yields. A rotation of crops reduces the 

 plant food supply in the soil (excepting nitrogen) even 

 more rapidly than the one crop system, and to maintain 

 good crop yields under rotation requires the addition of 

 mineral fertilizers or the application of liberal amounts of 

 farm manure. On the average farm the problem will be 

 best solved by using a certain amount of each. But to 

 go into this phase of the subject more in detail properly 

 belongs to a text-book on soil fertility. 



25. Suggested rotations. — The following are exam- 

 ples of rotations commonly recommended or in frequent 

 use : 



Com, oats, clover. 



Corn, wheat, clover. 



Corn, oats, wheat, clover. 



Corn, com, oats, clover. 



Corn, corn, oats, clover, wheat, clover. 



Corn, oats, wheat, hay, hay (mixed clover and timothy). 



Potatoes, wheat, clover. 



Potatoes, wheat, alfalfa, alfalfa. 



Cowpeas (or soy beans), wheat, hay, hay (mixed). 



Alfalfa 4 years, com 2 years, oats or wheat 1 or 2 years. 



Corn, corn, oats, hay (clover and timothy), pasture. 



Oats (or barley), beans, wheat, hay. 



Corn, barley, wheat, clover and timothy 1 or 2 years. 



Rye, hay, potatoes, oats or barley. 



Wheat, hay, potatoes, beans. 



Tobacco, rye or wheat, clover. 



In almost any of the above rotations one or two catch 

 crops may be grown and plowed under without adding 



