54 CLOVERS 



soon after the seed is sown. Considerable quantities 

 of earth must needs be apphed by this method. 



It should be remembered that each class of 

 legumes has its own proper bacteria. Because of 

 this, inoculation can only, or at least chiefly, be ef- 

 fected through the use of soils on which that par- 

 ticular class of legumes have grown, or which are 

 possessed of bacteria proper to that particular species. 

 In other words, bacteria necessary to the growth of 

 vetches will not answer for the growth of clovers, 

 and vice versa. Nor will the bacteria requisite to 

 grow medium red clover answer for growing alfalfa. 

 In other words, the bacteria proper to the growth of 

 one member of even a family of plants will not al- 

 ways answer for the growth of another member of 

 the same. But in some instances it is thought that 

 it will answer. The study of this phase of the ques- 

 tion has not yet progressed far enough to reflect as 

 much light upon it as could be desired. It is cer- 

 tainly known, however, that alfalfa will grow on 

 soils that grow burr clover (Medicago maculata) 

 and sweet clover (Melilotus alba), hence the infer- 

 ence that soil from fields of either will inoculate for 

 alfalfa. 



Nitragin is the name given by certain German in- 

 vestigators to a commercial product put upon the 

 market, which claims to be a pure culture of the 

 root tubercle organism. These cultures were sold in 

 the liquid form, and it was customary when using 

 them to treat the seed with them before it was 

 planted. Their use has been largely abandoned, be- 

 cause of the few successes which followed their use 



