The Fixation of Nitrogen 



133 



tained very active nitrogen-fixing organisms; these were Nos. 

 3, 7, and 9. 



TABLE II. 



Assimilation of Nitrogen by Means of Bacillus radieieola in Sand for 



Four Weeks. 



Pot No. Culture. Nitrogen in 100 gr. of Sand. 



1 . . . .Alfalfa, Pure 4.00 Mg. 



2 . . . .Alfalfa, Pure 7.00 Mg. 



3 . . . .Alfalfa, Pure 16.00 Mg. 



4. . . .Alfalfa, Mixed 14.00 Mg. 



5 . . . .Red Clover, Pure 6.00 Mg. 



6 . . . .Red Clover, Pure 5.00 Mg. 



7 ... .Red Clover, Pure 13.00 Mg. 



V;. .Red Clover, Mixed 10.00 Mg. 



9. . . .Crimson Clover, Pure 6.00 Mg. 



10.. . .Crimson Clover, Pure 7.00 Mg. 



11.... Crimson Clover, Pure 10.00 Mg. 



12 ... .Crimson Clover, Mixen 21.00 Mg. 



13 . . . .Cowpea, Pure 5.00 Mg. 



14 . . . .Cowpea, Pure 7.00 Mg. 



15 ... .Cowpea, Pure 16.00 Mg. 



16. . . .Cowpea, Mixed. . 22.00 Mg. 



In sterilized sand that is kept moist with a glucose solution 

 containing some potassium Diphosphate, the legume bacteria 

 will grow arid assimilate nitrogen. Somewhat larger amounts 

 of nitrogen were fixed in sand than in the liquid medium, but 

 in both the amounts were small as compared with the assimila- 

 tion of nitrogen in the presence of the host plant. Here again 

 the «mixed cultures assimilated more nitrogen than the pure 

 cultures. After the samples were taken from each of the pots 

 and analyzed, the pots were removed to the greenhouse and 

 planted with buckwheat. For the first week the growth in all 

 pots was about the same. At the end of the third week the plants 

 in the uninoculated pots began to wilt while the plants in the 

 inoculated pots continued to grow. The cut below shows 

 inoculated and uninoculated pots. 



