138 COTTON 
Where this method is practiced, itcombines easily 
with winter or cover crops like clover or rye, and as 
plant food is released it is stored in stem, root, and 
leaf of the growing plant, thus leaving a wealth of 
plant food and humus in the soil for other crops 
that come later. 
GREEN MANURES 
A green crop plowed under offers another quick 
way of improving the productive power of the soil. 
For this work you can use clover, rye, or cow- 
peas. Clover and cowpeas are preferred, since 
they add humus abundantly, and at the same time 
gather atmospheric nitrogen and store it in the soil. 
