n 9 



take place during humification result in the produc- 

 tion of acid products. This is simply the result of 

 the action of the ferments. The acids then act upon 

 the soil bases and produce humates or organic salts. 

 In many fermentation changes there is first the pro- 

 duction of some chemical compound, and then the 

 action of this compound upon other bodies. In ren- 

 dering plant food available, as in nitrification and 

 humification, it is the final product, and not the first 

 product of the organism, which is of value. 



149. Inocculating Soils with Organisms. In grow- 

 ing leguminous crops on soils where they have never 

 before been produced, it has been proposed to supply 

 the essential organisms which assist the crops to ob- 

 tain their nitrogen. For example, if clover is grown 

 on new land, the soil is liable to be deficient in the 

 organisms which assist in the assimilation of nitrogen 

 and which are present in the root nodules of the 

 plant. If these organisms are supplied, better condi- 

 tions for growth exist. Some soils are benefitted by 

 inocculation, while others are not. The extent to 

 which it is necessary to inocculate different soils with 

 organisms for the assimilation of nitrogen, has not yet 

 been determined by actual field experiments. 



150. Loss of Nitrogen by Fallowing Rich Lands. 



Summer fallowing creates conditions favorable to 

 nitrification. A fallow is beneficial to a succeeding 

 crop because of the nitrogen which is rendered avail- 

 able. If a soil is rich in nitrogen and lime, summer 

 fallowing causes the production of more nitrates than 



