136 



wliicli tlM' ^;(>il is cin-iclKMl l»y llic ;;T()\vin^- of oowpeas. 

 The ^I'owiim IcnNcs in llic air-dry condition contain 

 nc-ai'l.v Iwicc as lar^c a ijcrcciitamc of iiitro«i;on as the 

 tine sU'ins, and more tlian twice as much as the coarse 

 stems and loots and fallen material. 



Antoiniix of air-dnj inuivnal and nifrof/cn afforded hij 

 different jnirts of the eoicijea plant on one acre 

 {average of six varieties) 



Air dry 

 material. 



I Nitrogen. 



In leaves retained on vines ... 



In fine stems 



In coarse stems 



In pods, blooms, etc 



In fallen leaves and leaf stalks 

 In roots and 2-incli stubble .... 



Total 



Libs. 



501.0 



401.6 



438.8 



325.0 



357.3 



411.7 



2435.4 



Lbs. 



18.00 

 7.66 

 6.61 



*9.75 

 5.97 

 5.68 



53.67 



♦Assuming 3% of nitrogen in thoroughly air-dry pods. 



The amount of nitrogen stored np by a poor crop of 

 cowpeas growing on an acre, 53.67 pounds, is equivalent 

 to that contained in 767 pounds of cotton seed meal. It 

 should be remembered that an undetermined portion of 

 this nitrogen came from the soil, though on a soil as 

 lx>or as this the nitrogen derived from the air probably 

 constituted b}^ far the larger portion of the total nitro- 

 gen utilized by tlie jdant. 



In the stubble, roots, and fallen material there Avas 

 11.65 pounds of nitrogen per acre or the same amount 

 as is contained in 162 pounds of cotton seed meal. 



Of the total nitrogen in the entire plant 22 per cent, 

 was found in the roots, stubl)le and fallen material. 



An experiment somewhat similar to the preceding 

 was made in 1900, using only a single variety, Wonder- 

 ful or Unknown. The seed were planted in drills 2J 



