408 THE PRINCIPLES OF SOIL MANAGEMENT 



faction. (2) Ammonification. (3) Nitrification. (4) 

 Denitrification. 



278. Decay and putrefaction. Decomposition of 

 the nitrogenous organic matter of the soil, consisting 

 largely of the proteins, begins with either one of two 

 processes decay or putrefaction. Decay is produced 

 by aerobic bacteria, and naturally occurs when the 

 conditions are most favorable for their development. 

 When the conditions are otherwise, the growth of 

 these bacteria is checked, and then further decom- 

 position would be extremely slow were it not for the 

 other process putrefaction. Putrefaction is produced 

 by anaerobic bacteria. In the same body, and conse- 

 quently in the same soil, decay and putrefaction may 

 be in progress simultaneously, decay taking place on 

 the outside and on the surfaces of other parts exposed 

 to the air, while putrefaction occurs on the interior, 

 where the supply of oxygen is limited. By means of 

 the two processes, decomposition is greatly facilitated. 



Decay produces a very rapid and complete decom- 

 position of the substance in which it operates, most of 

 the carbon and hydrogen being quickly converted into 

 carbon dioxid and water, and the nitrogen into am- 

 monia and probably some free nitrogen. The latter 

 is possibly due to the oxidation of ammonia, thus 



4 NH 3 + 3 2 = 6 H 2 + 2 N 2 . 



The sulfur of the proteins finally appears in the form 

 of sulfates. 



What the intermediate products are has not been 

 determined, but in the decay of meat, where there was 



