284 



Soil Inoculation. 



[AUG., 



the light of fertilisers, or as capable of increasing the yield 

 under average conditions. They do not contain nitrogen 

 itself, but bacteria, which make it possible for the legumes to 

 secure nitrogen from the air (through the formation of root 

 nodules). Where the soil is already adequately supplied 

 with these bacteria, it will not usually pay to practice 

 artificial inoculation. 



2. When the soil is already rich in nitrogen. 



It is neither necessary nor profitable to inoculate a soil rich 

 in nitrogen when sowing legumes. Not only does the available 

 nitrogen in the soil render the formation of nodules less neces- 

 sary, but the nitrogenous materials in the soil largely prevent 

 the bacteria from forming nodules. 



Any increased virility in nitrogen-fixing power possessed by 

 any of the types of bacteria yet distributed may be rapidly 

 lost in a soil containing an abundance of nitrogen, because 

 the bacteria are in a medium in which there is no demand 

 for activity in securing atmospheric nitrogen. 



When Failure is to be Expected. — Inoculation will fail where 

 other conditions (aside from the need of bacteria) are not 

 taken into account, among which are the following — ■ 



1. In soil that is acid and in need of lime. 



Liming to correct acidity is as important for the proper 

 activity of the bacteria as for the growth of the plants. 



2. In soil that is deficient in fertilisers, such as potash, 

 phosphoric acid, or lime. 



The activity of the bacteria in securing nitrogen from the air 

 and rendering it available to the legumes does not do away 

 with the need for such fertilising elements as potash and 

 phosphorus. 



3. It must also be remembered that inoculation does not 

 " act like magic " ; it will not overcome results due to bad seed, 

 improper preparation and cultivation of ground, and decidedly 

 adverse conditions of weather or climate. 



In the use of the cultures, also, failure is almost certain 

 where the directions are not carefully studied and intelligently 

 followed. 



