DECOMPOSITION OF NON-NITROGENOUS ORGANIC MATTER 



449 



optimum temperature for the action of cellobiase, while Pringsheim 

 found that cellulose decomposition will take place at temperatures of 

 20° to 70°. 



As to the influence of soil reaction, Hellstrom 69 demonstrated in 1899 

 that the action of lime on peat soils is not so much to serve as a nutrient 

 for plants as to stimulate the decomposition of the organic substances 

 in the peat and neutralize the acid products formed. Christensen 70 

 also found that a basic soil shows a much higher cellulose decomposition 

 than a base-free soil. The results of Charpentier and Barthel 65 seem 

 to prove that liming of soil has no favorable action at all upon cellulos 



Cellulose 



6 8 

 0.i 



0.6 



O.i 

 0.* 



0.3. 



Oi 



04 







Sandy soil 



Clay 50il I 



Clay soil 2 



Peat soil 







Pay; 



60 



90 



120 



210 



Fig. 24. Influence of soil type upon the decomposition of cellulose (after 

 Charpentier). 



decomposition. This is due largely to the fact that the process is 

 carried out both by fungi and bacteria. The reaction of the soil no 

 doubt influences the type of organisms taking an active part in cellu- 

 lose decomposition, but not the process itself. Since various fungi and 

 various bacteria decompose cellulose actively, a change in reaction will 

 favor the development of either one group or another, while the actual 

 amount of cellulose decomposed may be influenced only inappreciably. 

 However, the decomposition of the organic matter of the soil itself, 

 such as "humus" of mineral soils or peat and other decomposed or 

 semi-decomposed organic materials may be greatly stimulated by the 



69 Hellstrom, P. 1909. Ref. Charpentier, 1921 (p. 431). 



70 Christensen, 1915 (p. 578). 



