338 



BOARD OF AGRICULTURE. [Pub. Doc. 



Crops for Green-manuring compared. 



Examination of this table shows that the soy bean gives a 

 larger amount of each of the important elements of plant food 

 than either of the other crops under consideration. It 

 furnishes more than double the quantity of each of the im- 

 portant elements of plant food contained in the cow pea. 

 In comparing different crops as soil improvers we have to 

 consider chiefly the amount of nitrogen they contain, for 

 nitrogen is the only important element of plant food which 

 can be increased in amount in the soil by green-manuring. 



The cow pea is highly praised in many quarters as a crop 

 for soil improvement. The soy bean, in my opinion, pos- 

 sesses numerous advantages over it for that purpose. The 

 cow pea does not ripen seed here while the soy bean does. 

 It is well known that legumes take nitrogen from the air in 

 largest proportion as they approach maturity, hence the crop 

 which matures will enrich the soil in this element to a greater 

 extent than one which does not. The cow pea, while doubt- 

 less valuable further south, both for fodder and for green- 

 manuring, is therefore believed to be inferior to the best 

 varieties of the soy bean for these purposes. 



The number of varieties of this bean is large. Among 

 those experimented with at Amherst the medium green proves 

 to be best. This is confidently recommended for fodder, 

 to be used green or to be put into the silo with corn or with 

 millet, or for green-manuring. It must be planted in drills ; 

 it does best upon medium or moderately heavy soils and 

 about one-half bushel of seed per acre is required. 



The horse bean is not recommended for Massachusetts as 

 it seems to be subject to blight, which seriously lessens its 

 productiveness. 



