FIELD CROPS 629 



seed all insect life is readily destroyed by treatment with carbon 



* 1 T- J 



Disulpmd. 



Cowpeas may be thrashed with an ordinary grain thrasher. 

 In this case the riddles are adjusted for cowpeas and satisfactory 

 screens are provided. The most essential point in thrashing cow- 

 peas is to maintain a low and even speed of the cylinder, 300 to 400 

 revolutions per minute, while the rest of the machine should be ad- 

 justed to run at least as fast as for thrashing wheat or oats. Some 

 operators prefer to have a greater clearance between the cylinder 

 and concave spikes than for grain thrashing, while others do not 

 think this an advantage. While expert operators sometimes do 

 very satisfactory work with an ordinary grain separator, there are 

 three important difficulties encountered: (1) Too many of the pods 

 pass through with the straw unopened; (2) the machine is easily 

 choked by the tangled vines wrapping around the cylinder; and 

 (3) the percentage of cracked peas is usually large. To overcome 

 these difficulties several modifications of thrashing machines have 

 been devised so as to adapt them for handling cowpeas. 



It is very essential in thrashing cowpeas that there be sufficient 

 power to give a uniform speed to the separator. It is also highly 

 desirable that the cylinder be kept uniformly full in order to get 

 the best results, as runnig empty means an increase in the number 

 of cracked peas. 



The price of cowpea thrashers now on the market ranges from 

 $300 to $600, exclusive of the engine. If the peas are stacked or 

 put into a barn so they need not be thrashed immediately, one 

 machine will be sufficient for 2,000 acres, as the crop from 20 acres 

 can readily be handled in one day. As a rule only a moderate 

 acreage of cowpeas for seed should be grown by any one farmer,, 

 as unfavorable weather may cause great difficulty at harvest time.' 

 It is very desirable to have enough cowpeas for seed grown in a 

 community to justify the local ownership of a thrashing machine. 



Cowpeas for soil Improvement. The beneficial results ^of 

 growing cowpeas are due largely to the ability of the plants^ like 

 those of alfalfa and red clover, to take nitrogen from the air by 

 means of the bacteria which live in the nodules on the roots. Cow- 

 peas also improve markedly the physical condition of the soil. This, 

 taken in connection with their ability to produce a crop quickly on 

 even the poorer soils, makes the cowpea particularly valuable both 

 as a catch crop and in regular rotations when utilized either for 

 hay or seed production. (F. B. 318; Del. Col. A. E. S. 46; Purdue 

 U. A. E. S. 117, 139, 149; Iowa Ag. Col. E, S, 45; La. A. E. S. 111.) 



