120 SOILS AND FERTILIZERS 





134. 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. 



In order to allow nitrification to proceed, all of these 

 conditions must be satisfied. The process is fre- 

 quently checked because some of the conditions, as 

 presence of a basic compound, are unfulfilled. 



135. Food for the Nitrifying Organisms. — All 



living organisms require a supply of food and one of 

 the food requirements of the nitrifying organism is a 

 supply of phosphates. In the absence of phosphoric 

 acid, nitrification cannot take place. The change 

 which the phosphoric acid undergoes in serving as 

 food for the nitrifying organism is unknown, but it 

 doubtless makes the phosphoric acid more available as 

 plant food. The principal organic food of the nitrify- 

 ing- organism is the organic matter of the soil. 

 Organic matter, only when incorporated with soil, can 

 serve as food for the nitrifying organism. In the pres- 

 ence of a large amount of organic matter, as in a 

 manure pile, nitrification does not take place. The 

 process can take place only when the organic matter 

 is largelv diluted with soil. Under favorable condi- 



