The Bulletin. 



37 



would be well to apply 200 to 400 pounds of basic slag or rock phos- 

 phate per acre, as this fertilization is for both the wheat and clover 

 crops. 



An application of 1,000 pounds of rock phosphate to the crop of 

 clover before it is turned under in the fall should furnish sufficient 

 phosphoric acid for the crops of the second period of this rotation. 

 Within a comparatively short time enough nitrogen should be fur- 



Plate 9. — Soja Beans Growing in Rows with Corn, 1910. 



nished by the soja beans, the clover, and the roughage, or stable 

 manure if crops are fed, that the nitrate could be largely if not 

 entirely dispensed with. The application of rock phosphate and 

 lime should be made every three years. Livestock farming in con- 

 nection with this rotation would materially help in improving the 

 productivity of these soils. 



FOUR-YEAR ROTATIONS. 



A good four-year rotation is the same as the above with oats and 

 soja beans following corn the second year. 



Another four-year rotation wdiich could be adopted in this sec- 

 tion is : 



