500 PRINCIPLES OF SOIL MICROBIOLOGY 



mum; the gases formed consist of C0 2 , CH 4 , H 2 and NH 3 . Under 

 aerobic conditions, there is a much greater loss of dry matter with a 

 much greater decomposition of the nitrogenous compounds. Hydro- 

 gen and methane are not found in the gases. There is no ammonia 

 accumulation, but nitrates are formed in the outer layers; with in- 

 complete aeration, gaseous nitrogen is formed. Various groups of 

 bacteria and fungi are active in the process of formation of ammonia 

 in manure, but not with equal rapidity. According to Conn and 

 Collison, 76 the strong proteolytic and gelatin liquefying organisms, 

 like Bac. cereus and Bad. fluorescens, are not able to give off ammonia 

 in quantities comparable to those given off from unsterilized manure. 

 Conn found that a minute, gram-negative, non-motile, non-spore 

 forming rod, Bad. parvulum was able to give off from manure, in pure 

 culture in the laboratory, amounts of ammonia, equal to or greater 

 than those obtained from unsterilized manure. The decomposition of 

 manure in the pile may not necessarily be carried on by the same 

 organisms as in the soil. Bad. fluorescens, which was found to be 

 relatively less active in the manure pile, was very active in the forma- 

 tion of ammonia from manure in the soil. 77,78 



Nitrogen transformation in the decomposition of organic matter in the 

 soil. When nitrogenous organic substances are added to the soil, a 

 group of complex reactions will result as far as the nitrogen is concerned : 



(1) The hydrolysis of the proteins into polypeptides and amino acids, with the 

 liberation of some ammonia. (2) This is followed by the decomposition of the 

 amino acids and other products of protein hydrolysis, with a further liberation 

 of ammonia. (3) Synthesis of microbial protoplasm, which will lead to a stor- 

 ing away of a part or the whole of the ammonia nitrogen; the greater the quan- 

 tity of available non-nitrogenous organic matter accompanying the nitrogenous 

 substances, the greater will be the synthesis of microbial protoplasm, leading 

 to a greater assimilation of the nitrogen and to a smaller accumulation of am- 

 monia. (4) Various soil conditions, as well as differences in the composition of 



76 Conn, H. J., and Collison, R. C. A study of certain bacteria involved in 

 the ammonification of manure. N. Y. Agr. Exp. Sta. Bui. 494. 1922. 



77 Conn, H. J., and Bright, J. W. Ammonification of manure in soil. N. Y. 

 Agr. Exp. Sta. Tech. Bui. 67. 1919. 



78 Further information on the conservation of manure and the changes taking 

 place in manure during storage is given by Lohnis, F., and Smith, J. H. Die 

 Veranderungen des Stalldiingers wahrend der Lagerung und seine Wirkung im 

 Boden. Fiihling's landw. Ztg. 1914, 153-167; Lemmermann, O., and Weissmann, 

 H. Untersuchungen iiber die Konservierung der Jauche durch verschiedene 

 Zusatzmittel. Landw. Jahrb., 52: 297-341. 1918. 



