398 



FIELD CROPS 



from one-eighth to one-quarter of an inch. The size of the 

 plant, the habit of growth, and the size and color of the seeds 

 vary even more than these characters of the cowpea. While 

 most of the varieties are erect and vary in height from 1 to 4 

 feet, some sorts have small seeds, small leaves and a trailing 

 habit, the vines reaching a length of several feet. The most 



prominent varieties are Mam- 

 moth, Ito San, and Early 

 Yellow. 



507. Importance. The soy 

 bean does not yet occupy a very 

 prominent place in the United 

 States, though in China and 

 Japan it is one of the most im- 

 portant crops for the production 

 of grain and oil. As the plant 

 is less easily injured by frost 

 than the cowpea, it can be grown 

 farther north. Its greatest use- 

 fulness will probably be along 

 the northern border of the sec- 

 tion where cowpeas are grown, 

 from Kansas, Kentucky, and 

 Maryland northward. The soy 

 bean grows very well on poor 

 and sandy lands, and may be- 

 come as important for the building up of poor soils and 

 for forage in this region as the cowpea now is farther south. 

 608. Growing the Crop. The methods of growing soy 

 beans differ little from those in use in the cultivation of the 

 cowpea crop. The plants are more often grown in rows and 

 cultivated, as the crop is generally grown for the production 

 of seed as well as forage. The preparation of the soil should 



Fig. 123. Soy bean plant. Note 

 the nodules on the roots. 



