FOR BETTER CROPS IN THE SOUTH 17 



Nitrogen — The element nitrogen ought never to be bought 

 in general livestock or grain farming. The atmospheric pres- 

 sure is fifteen pounds to the square inch. Of this, about twelve 

 pounds pressure is due to the nitrogen contained in the air. If 

 we compute the value of this nitrogen at fifteen cents a pound, 

 the price commonly paid for the nitrogen in commercial ferti- 

 lizers, we find about $11,000,000 worth of nitrogen resting on 

 every acre of the earth's surface. 



It is true that such crops as corn, oats, wheat, timothy, cot- 

 ton and tobacco have no power to make any direct use of this 

 atmospheric nitrogen, but there is a class of plants known as 

 legumes, including such valuable agricultural plants as red 

 clover, alsike, alfalfa, crimson clover, cowpeas, soy beans, vetch, 

 etc., upon the roots of which there are or should be small nodules 

 or tubercles, varying from the size of pin heads upon clover roots 



r~ 





Manure exposed in this way loses its fertilizing 

 elements very rapidly 



to that of peas upon soy beans, in which live great numbers of 

 very minute microscopic organisms called bacteria, which have 

 power to take nitrogen from the air as it enters the pores of the 

 soil, and to cause this free gaseous nitrogen to combine with 

 other elements in suitable form for plant food which is then 

 taken up by the clover or other legume for its own growth. 



If the roots and stubble are left to decay in the ground, the 

 nitrogen which they contain becomes available for succeeding 

 crops of corn or other grains or grasses, but on land of moderate 

 productive power the soil will furnish as much nitrogen to the 

 clover crop as will be contained in the roots and stubble after 

 the hay and seed crops are harvested. If the entire legume crop 

 is plowed under as green manure, then all of the nitrogen taken 

 from the air is left in the soil for succeeding crops. 



If the crops are fed to animals provided with plenty of 

 absorbent litter or bedding, as straw or refuse shredded corn 

 fodder, so that all liquid excrement is saved, then about 75 per 



