224 



FIELD CROPS FOR THE COTTON-BELT 



TABLE 19. APPROXIMATE AMOUNTS OF NITROGEN, PHOSPHORIC ACID 

 AND POTASH REMOVED BY A 50-BusHEL CROP OF CORN (Pounds) 



When total yield of dry matter to the acre is considered, 

 corn does not make an excessive demand on the soil for 

 food. Nevertheless, the amounts removed are appreciable. 

 The nitrogen should always be returned in amounts greater 

 than that contained in the crop to offset the loss from 

 leaching. The phosphoric acid and potash should be re- 

 turned in all cases except where the soil contains large 

 natural supplies of these materials. 



It should be noticed that two-thirds of the total nitrogen 

 and the greater part of the phosphoric acid removed fr.om 

 the soil are in the grain. The stover contains nearly 

 three-fourths of the total potash. Even if only the grain 

 was removed and the stover returned to the soil the supply 

 of nitrogen and phosphoric acid in the land would be 

 materially decreased. Sound fertilizer practice, however, 

 is not based on supplying to the soil the plant-food constit- 

 uents in the same proportion in which they are removed 

 in crops. 



273. Soils and fertilizers. The nature and amount 

 of fertilizing materials most profitable for corn are deter- 

 mined largely by the character of the soil on which the crop 

 is grown. The method of determining the fertilizer needs 

 of soil for cotton is given in paragraph 100. This same 

 principle is equally applicable to corn. That best results 



