GREEN MANURES 



623 



When other conditions are equal, it is of course always 

 better to choose a leguminous green manure in preference 

 to a non-leguminous one, because of the nitrogen that may 

 be added to the soil. However, it is so often difficult to 

 obtain a catch of some of the legumes that it is poor 

 management to turn the stand under until after a number 

 of years. Again, the seed of many legumes is very expen- 

 sive, almost prohibiting their use as green manures. 

 Among the legumes most commonly grown as green ma- 

 nures, cowpeas, soy beans, and peanuts may be named. 

 Many of the other legumes do not so fit into the common 

 rotations as to be handily turned under as a green manure. 



For the reasons already cited, the non-legumes have in 

 many cases proved the more popular and economic as 

 green manures. Rye and oats are much used because 

 of their rapid, abundant, and succulent growth and be- 

 cause they may be accommodated to almost any rotation. 

 They are hardy and will start on almost any kind of a 

 seed bed. They are thus extremely valuable on poor soils. 

 Often the value of such a green manure as oats is greatly 

 increased by sowing peas with it. The advantages of a 

 legume and a non-legume are thus combined. 



