NITRIFICATION Iig 



It is to be regretted that in the cultivation of large 

 areas of land to staple crops as wheat, corn, and cotton, 

 the methods of cultivation are such as to decrease the 

 nitrogen content and crop-producing power of the soil 

 when this can be prevented. 



NITRIFICATION 



132. Former Views Regarding Nitrification. — 



The presence of nitrates and nitrites in soils was 

 formerly accounted for by oxidation. The theory 

 was held that the production of nascent nitrogen by 

 the decomposition of organic matter caused a union 

 between the oxygen of the air and the nitrogen of the 

 organic matter. The studies of fermentation bv 

 Pasteur led him to believe that possibly the formation 

 of nitric acid in the soil might be due to fermentation. 

 It was, however, 15 years later before the French 

 chemists, Schlosing and Miintz, established the fact 

 that nitrification is produced by a living organism. 



133. Nitrification Caused by Micro-organisms. 



— Nitrification is the process by which nitrates 

 or nitrites are produced in soils, by the workings of 

 organisms. Nitrification results in changing the com- 

 plex organic nitrogen of the soil to the form of nitrates 

 or nitrites. It is the process by which the inert 

 nitrogen of the soil is rendered available as crop food. 

 The organisms which carry on the work of nitrifica- 

 tion have been isolated and studied by Warington, 

 and by Winogradsky. 



