Various Kinds of Green-Manures 245 



The cowpea, soybean, and velvet bean as green-manure 

 crops.— Oa the sandy soils of the East, the cow- 

 pea, soybean, sand vetch, crimson clover, and velvet 

 bean have been used widely for the improvement of land. 

 In the cotton-growing states of the South, the cowpea 

 is almost indispensable as an aid in the maintenance of 

 the humus and the nitrogen of the soil. Because of the 

 long growing season and abundant rainfall, two crops of 

 cowpeas may be grown in a single season in some places. 

 With the cheap phosphates available to the farmers of 

 that region and the great supply of atmospheric nitrogen 

 at the disposal of the cowpea, the growing of cotton and 

 of corn is less difficult than formerly on poor soils. 

 Many acres that had been depleted of their fertility 

 and abandoned have been made highly productive. 

 The bacterial activities in the decomposition of the 

 cowpea vines and roots, or of the residues of other crops, 

 are scarcely suspended during the mild winters of the 

 South. Green-manuring must necessarily, therefore, 

 find there a more extensive application. 



In states Hke Alabama, Florida, and Louisiana, the 

 velvet bean promises to become a rival to the cowpea 

 as a green-manuring crop. It is fond of warm, moist 

 weather and produces, under favorable conditions, im- 

 mense quantities of plant substance. In experiments 

 with the velvet bean in the three states just mentioned, 

 the yields of green material per acre were 19,040 pounds, 

 22,919 pounds, and 21,132 pounds, respectively. The 

 corresponding yields of nitrogen were 213.9 pounds, 

 172.9 pounds, and 141.2 pounds, respectively. In the 

 experiments of the Alabama station, oats were seeded 



