24 BEAN CULTURE 



was found that if either plant was inoculated with 

 germs from the tubercles of the other, some tuber- 

 cles would be formed, but the organisms seemed to 

 be without the power of nitrogen assimilaton. If 

 the inoculation was continued a second season, or 

 through a second or third season of cultures, the 

 bacteria became nearly as efficient as those from the 

 roots of the same genus. To the organisms resulting 

 from such adaptations, the authors have given the 

 name "crossed" or "crossbred bacteria." When in- 

 oculations with these crossbred bacteria were made 

 upon their original host, they were found to have 

 nearly lost their ability of nitrogen assimilation on 

 the roots of that plant, showing little, if any, in- 

 creased nitrogen content over non-inoculated plants. 



Favoring tubercle formation. — Having the fact 

 fixed that bean roots carry bacteria capable under 

 proper conditions of assimilating nitrogen from the 

 air, the next question comes, how can the bean 

 grower facilitate accumulation. This may be done 

 in two ways: First, succeeding beans after beans, 

 and allowing nature to build up a strong colony of 

 bacteria; or second, if artificial inoculation is prac- 

 ticed, cultures may be used, or soil from a field 

 which has produced a crop of beans can be mixed 

 v.'ith that in the field under consideration. 



Much has been said relative to the efficiency of 

 inoculation culture for legumes. The Department of 

 Agriculture at Washington gained considerable no- 

 toriety through Doctor Moore in this connection. 

 The various conflicting evidences which can be 

 assembled warrant no specific and accurate deduc- 

 tions on what should be the practice of the farmer 

 relative to bean cultures. It cannot be disputed 



