39 



It will be noticed that the crop was very largely increased where the 

 sweet clover was ploughed in. Similar results were obtained with pota- 

 toes. The quantity of seed required per acre is from twenty-jfiye ;t0 

 thirty pounds. It should be sown from about July 25 to August Ifh — ff' 

 sown much later it is liable to wintei'-kill. It is believed that under the 

 right conditions it will give good results when sown in corn at the last, 

 cultivation but this has not yet Ijeen demonstrated at Amherst. 



The Cow Pea, Horse Bean and Hoy Bean. — These ei'ops require a 

 longer season for growth than most coming under this class, but all 

 may be valuable as soil improvers and they will therefore be briefly 

 spoken of. To show their probable value and for the purpose of coni- 

 pai'ing them with one another and with the crimson and sweet clover 

 the following table has been prepai-ed : — 



Crop^ for Green Manuring comijared. 



Crop. 



Cow pea, . 

 Soy beau, . 

 Horse bean, 

 Sweet clover, , 



CrimBon clover 



Green 

 Fodder 



Nitrogen 



(Ton.). (I'onnds). 



10 

 10 

 12 

 12 

 Hay, lbs. 

 4,388 



62 

 168 

 163.2 



108 



84.6 



Potash 

 (Pounds). 



36 



142 



Phosphoric 



Acid 

 (Pounds). 



20 

 40 

 19.2 

 31.2 



20.1 



Examination of this table shows that the soy bean gives a laro-er 

 amount of each of the important elements of plant food than either of 

 the other crops under consideration. It furnishes more than doulale the 

 quantity of each of the important elements of jjlant food contained in 

 the cow peas. In comparing diflerent 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 l)e 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, possesses numerous ad- 

 vantages 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 ni- 

 trogen from the air in largest ijroportion 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 doubtless 

 valuable further south, both for fodder and for green-manui'ing, is there- 

 fore believed to be inferior to the l)est varieties of the soy bean for these 

 purposes. 



The number of vai-ieties of this bean is large. Among those experi- 

 mented 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 moderatly heavy soils and 

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



The horse bean is not recommended for Massachusetts as it seems to 

 be subject to blight which seriously lessens its productiveness. 



