SOIL IMPROVEMENT 



105 



Second: Crops should rotate so as to secure most of their 

 nitrogen from the air. This is done by growing legumes, such 

 as clover and cowpeas. Their work in 

 improving the soil is more fully de- 

 scribed in the section on Green Ma- 

 nures. More and more, farmers are 

 realizing the importance and the 

 economy of raising legumes, and so 

 avoiding partly or wholly the expense 

 of buying nitrogen in fertilizers. 



Third: Crops should rotate so as to 

 have plants of different feeding capac- 

 ities and habits of growth follow one 

 another. The greater the difference in 

 all ways, growth, food needs, food- 

 getting power, and methods of cultiva- 

 tion, the better. Food unavailable to 

 plants with shallow fibrous roots, such 

 as wheat, is pumped out of the subsoil 

 by plants with deep taproots, such as 



Clover. ThuS the drain Of Crop-feed- Courtesy of Alabama Agricultural Station 

 ing is divided between SOil and SUb- i, rye after velvet beans; 2, rye from 

 SOil. Different methods Of Cultivation an equal area, after sweet potatoes. 



required by different crops improve soil conditions. All soils need 

 to be sometimes loosened, sometimes compacted. 



Fourth: Crops should rotate so as to make the best use of 

 the residue, or remains, of the preceding crop and of the manures 

 and fertilizers applied. Coarse manures are generally most 

 valuable when applied to strong-feeding crops to precede and 

 prepare for weak-feeding ones. Clover, for instance, is a strong- 

 feeding plant and it makes good use of stable manure; it stores 



