CROPS AND SOIL IMPROVEMENT 



from the standpoint of soil fertility because the 

 draft upon humus is heavy in a close rotation em- 

 bracing a tilled crop and small grain. The sod 

 should be chiefly clover, or manure should be used 

 in connection with commercial fertilizer. 



Grain and Clover. In the case of some soils 

 it is possible to grow a wheat or corn crop each 

 year, clover being grown as a catch crop. In the 

 long run, this practice will fail because the clover 

 will cease to make a thrifty growth when grown 

 so nearly continuously. It succeeds best on fertile 

 land. 



Potatoes and Crimson Clover. In some po- 

 tato-producing sections in warm latitudes it is a 

 not uncommon practice to grow potatoes year 

 after year on the same land, seeding to crimson 

 clover after the removal of the crop in August, 

 and plowing the clover down early in the spring. 

 Rye has been similarly used farther north. In 

 each instance available plant-food must be freely 

 supplied. The practice is a temporary expedient 

 of value, but probably cannot be pursued in- 

 definitely with profit. This is likewise true of 

 similar close rotations. 



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