Leguminous Green-Manures 247 



on velvet-bean stubble, on land where a crop of velvet 

 beans had been turned under, and on land where crab- 

 grass had been harvested. 



On the first of these plots, the yield of oats was at 

 the rate of thirty-eight bushels per acre, and on the third, 

 at the rate of seven bushels per acre. Evidently, the 

 preceding growth of velvet bean had benefited the 

 oats both on the land where the stubble and where the 

 entire crop of beans was turned under. The very large 

 amount of green material turned under on the second 

 plot reduced the yield of oats. Either the acidity intro- 

 duced into the soil or the loosening of the soil to too 

 great an extent, thus affecting adversely the moisture 

 conditions, was the cause. 



The great value of cowpeas as a green-manuring crop 

 is not restricted to the southern or southwestern states 

 proper. It has found a place in Maryland, Delaware and 

 New Jersey and has been used in other states of the 

 Atlantic seaboard, as well as in the Middle West. It 

 has rendered valuable service in these states, not only 

 in restoring worn-out soils, but, also, in the building up 

 of vast tracts of light, shifting sands. The bacteria- 

 producing nodules on the roots of the cowpea seem to 

 be widely distributed in these soils, and hence make 

 artificial inoculation unnecessary. The soybean, which 

 is related to the cowpea, has also been used as a green- 

 manure on light soils. It does well, however, also on 

 heavier soils, provided it is properly inoculated, and 

 is not as readily injured by cold weather. 



Crimson clover.-^- Cowpeas and soybeans are summer 

 crops and are serviceable for green-manuring purposes after 



