THE COWPEA AND THE VELVET BEAN AS FERTILIZERS. 



BY J. F. DUGGAR. 



Summary. 



This bulletin records the results of more than fifty ex- 

 periments conducted at Auburn during the past five 

 years, to ascertain the effects of cowpeas and velvet 

 beans in the improvement of the soil. The amount of 

 soil improvement has been determined by the incriease 

 in the yields of cotton, corn, oats, wheat and sorghum, 

 grown as first, second, third or fourth crops after the 

 stubble and roots of cowpeas or velvet beans or after 

 vines, stubble and roots of these plants have been plowed 

 under. The basis for determining this increase has 

 been the yield of each crop on plots where no leguminous 

 plant has recently grown. 



The fertilizing value of different varieties of cow- 

 peas was found to vary considerably, and is probably in 

 proportion to the luxuriance of growth. 



In two tests there was a slightly larger yield of corn 

 from plowing in cowpea vines very late in the fall 

 than from postponing the plowing until April ; but it is 

 regarded as generally best to plow in the vines not more 

 than a few weeks before the next crop is planted. 



The average for six varieties showed that when cow- 

 peas were at a suitable stage for mowing 36.6 per cent, 

 and in another case 39 per cent, of the dry weight of 

 the plant was available for fertilizing uses in stubble, 

 roots and fallen leaves. In the entire growth of cow- 

 peas on one acre there was contained in one case 53.7 

 pounds of nitrogen, in another 69.8, and in another 

 87.2, an average of 70.2 pounds of nitrogen per acre, 



