SOIL INOCULATIONS. 1 19 



SOIL INOCULATIONS. 



The need of bacterial action in the soil naturally suggests the 

 question whether the necessary activities may not be brought about 

 or increased by inoculating the soil with the desired bacteria, just as 

 a brewer inoculates his malt with yeasts. This plan has been tried 

 extensively by at least two different methods. 



Nitrogen Fixers, Alinit, Nitrifying Bacteria. Alinit is a 

 material placed on the market and widely used for a time. It was 

 said to be made from a pure culture of the bacteria that can fix free 

 nitrogen in the soil. Careful testing, however, failed to show any 

 favorable results from the use of alinit, and so it has been abandoned. 

 Other nitrogen fixers have also been tested as pure cultures inocu- 

 lated into soil, with like failure. The attempt to simulate nitrifica- 

 tion by the use of cultures of nitrifiers has likewise failed. 



Tubercle Bacteria of Legumes. Nitragin. As already 

 noticed, this commercial product, supposed to contain the bacteria- 

 producing root tubercles, was found to be a failure, although claims 

 are still made of the success attending the use of the New Nitragin 

 and of some of the other cultures of similar organisms. While 

 these may be found practical and while it would seem as if this 

 method would be likely, in the future, to become successful, at the 

 present time the results are so uncertain that a decision as to the 

 value of such inoculation for the developing of legume tubercles must 

 be held in abeyance. Inoculations with legume earth, however, have 

 proved to be of great value, and whenever it is desired to cultivate 

 a legume in a soil where it does not readily grow, this inoculative 



excretes into the soil certain substances that serve as poisons to another 

 similar crop on the same soil. It is said that practically all soils at all times 

 contain a sufficiency of food, but that the accumulation of these excre- 

 tions after a time renders the soil incapable of supporting a satisfactory 

 crop. The value of fertilizers is not to give food, but to neutralize these 

 excretions, and that a proper rotation of crops will serve just as well, since 

 the excretions from one kind of plant, while injurious to the same plant, 

 will not injure a different kind of plant. Such a conception would largely 

 revolutionize the methods of treating the soil, since, if accepted, it would 

 lead to the abandonment of any attempt to feed the crops and would re- 

 place such methods by those designed simply to remove the poisonous 

 excretions. This theory as to soil fertility would bring into greater 

 prominence the agencies of soil bacteria, but it is very vigorously disputed 

 and certainly has not reached a position where it warrants an acceptance. 



