238 



SOILS AND FERTILIZERS 



inorganic matter. By the second form of transfer the nutri- 

 ents in this available form are deposited in the upper soil from 

 which most crops draw the larger part of their nutriment. 



297. Crops used for green-manuring. — The following table 

 contains a list of the plants commonly used as green-manures 

 both in cultivated fields and in orchards, together with some 

 information as to the season of the year when they may be 

 used and whether adapted to northern or southern conditions. 



Table 56. Crops Used as Green-Manures 



Legumes (annual) 



Canada field pea 



Hairy vetch 



Crimson clover 



Peanut 



Velvet bean 



Soy bean 



Cowpeas 



Legumes (biennial or perennial) 

 Red or mammoth clover . . . 



Alsike clover 



Alfalfa 



Sweet clover 



Non-Legumes 



Rye 



Oats 



Buckwheat 



Cowhorn turnips 



Mustard 



Rape 



Season 



summer 



winter 



winter 



summer 



summer 



summer 



summer 



one year at least 

 one year at least 

 one year at least 

 one year at least 



winter 



fall or early spring 



fall and summer 



summer 



summer 



summer and fall 



Region 



Northern states 

 Northern and southern states 

 Middle and southern states 

 Middle and southern states 

 Middle and southern states 

 Middle and southern state3 

 Southern states 



Northern states 



Northern states 



Northern and southern states 



Northern and southern states 



Northern and middle states 

 Northern and middle states 

 Northern states 

 Northern states 

 Northern states 

 Northern states 



A soil that has become less productive under cultivation, 

 and that must be improved before profitable crops can be 

 grown, receives more benefit from the use of legumes than 

 from any other crop. The legume to use is naturally the one 

 best adapted to the region in which the soil is located. 



The perennial or biennial legumes are too slow of growth 

 really to be considered green-manure crops. They are like 



