134 The Plant World 



Fig. 1.— -Buckwheat Planted in Sand Cviltures. 



Xo. I. Uninoculated. 



No. 2. Inoculated with a pure culture. Red Clover 



No. 3. Inoculated with a pure culture. Crimson Clover. 



No. 4. Inoculated with a pure culture. Alfalfa 



No. 5. Inoculated with a pure culture Red Clover 



No. 6. Inoculated with a mixed culture. Red Clover 



No. 7. Inoculated with a mixed culture Alfalfa 



For the investigation of assimilation of nitrogen in soil 

 a clay soil was procured from the Station Plats which had the 

 following analysis: 



SOIL SAMPLE FROM PLAT NO. 24. 



Total Nitrogen 106 



Humus 1.12 • « 



Phosphoric Acid, N5HN0 3 22.3 pts. per million" * io 



Potash, N5HN0 3 193.2 pts. per millitxwi ni 



Potash, water soluble 24.2 pts. per miliiqn ffo j j 



As in the case of the sand, small wire baskets were filled -win fa 

 this soil and inoculated with cultures from different legumes* 

 These were treated just the same as the sand except the soil was 

 not previously sterilized. The assimilation would hardly beiais-j 

 great in this clay type as in an open and more easily aerated 

 soil, yet, on the average, the amount of nitrogen fixed by nateans 

 of Bacillus radicicola was much more in soil than in sterileisandt 



