NITRIFICATION 



135. 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 de- 

 composition of organic matter caused a union be- 

 tween the oxygen of the air and the nitrogen of the 

 organic matter. Fermentation studies by 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 nitrifi- 

 cation is produced by a living organism. 



136. Nitrification Caused by Micro-organisms. 

 Nitrification is the process by which nitrates or 

 nitrites are produced in soils, by the workings of or- 

 ganisms. 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 

 nitrification have been isolated and studied by War- 

 ington, and by Winogradsky. 



137. Conditions Necessary for Nitrification are : 



1. Food for the nitrifying organisms. 



2. A supply of oxygen. 



3. Moisture. 



4. A favorable temperature. 



5. Absence of strong sunlight. 



6. The presence of some basic compound. 



(8) 



