70 GENERAL CONSIDERATIONS 



can be sown broadcast, using from three pecks to 

 three bushels of seed per acre. It is more usual, 

 however, to plant in drills about three feet apart. 

 This only requires about half as much seed and al- 

 lows of giving one or two cultivations. If supplied 

 with potash and phosphoric acid, they will make a 

 rank growth even on very poor lands. The use of a 

 fertilizer that supplies these elements is often re- 

 quired to secure the best results. They are very 

 efficient as nitrogen gatherers and thus serve to build 

 up and enrich the soil very rapidly. Practically all 

 soils at the South and in the adjacent tropics are 

 plentifully supplied with the appropriate tubercle- 

 forming bacteria for this plant, so that soil inocula- 

 tion is seldom necessary. There are many varieties 

 of cowpeas. These differ not only in the color and 

 size of the seed, but in time of maturity and habit of 

 growth. The whippoorwill, or speckled pea, matures 

 very early and has an erect, almost bushlike habit 

 of growth. It yields a large amount of seed, but 

 produces less leaves and vines than some of the 

 others. It can be planted farther north than the 

 other kinds, maturing well in Kansas, central Illinois, 

 and Delaware. It is also particularly useful when 

 the land can only be occupied for a short time, and 

 from its erect habit of growth it is easily cut and 

 handled in making hay. The iron pea, unlike the 

 whippoorwill, produces a large amount of vines and 

 leaves, but usually ripens a less amount of seed. It 

 remains green longer than any of the others and is 

 thousrht to be more resistant to certain diseases. At 

 the South, wliere the season is long, it is one of the 



