444 



PRINCIPLES OF SOIL MICROBIOLOGY 



permits the measurement of nitrogen transformation as an index of 

 cellulose decomposition, since they run parallel. 



There is good evidence that fungi are chiefly responsible for the 

 decomposition of celluloses in acid, humid soils under aerobic conditions. 

 When the soil is partially sterilized to eliminate the fungi, cellu- 

 lose decomposition comes practically to a standstill. When cellu- 

 lose is added to the soil, especially in the presence of an available 

 source of nitrogen, the fungi develop much more abundantly than 



TABLE 36 

 Decomposition of cellulose by pvre cultures of microorganisms 



ORGANISM 



Trichoderma koningi 



Trichoderma koningi 



Fusarium 115 



Aspergillus fumigatus 



Aspergillus glaucus 



Aspergillus wentii 



Aspergillus fuscus 



Penicillium of soil Group III . 



Mucor racemosus 



Z ygorhynclius molleri 



Cunninghamella elegans 



Actinomyces violaceus-ruber . . . . 



A ctinomyces cellulosae 



Actinomyces viridochromogenus 



Bacterium fimi ia 



Bac. cereus 



Bac. vulgalus 



CELLULOSE 



either the bacteria or actinomyces; 50 this can be readily demonstrated 

 both by the plate and direct microscopic methods. 



Cellulose decomposition in manure. Thirty to forty per cent of the 

 dry weight of manure consists of cellulose and 20 to 30 per cent of 

 pentosans. 51 When manure undergoes decomposition, whether in the 



49 This organism of Kellerman et al., was from stock culture; Spirochaeta 

 cytophaga studied later was found to be much more active and decomposed al- 

 most as much cellulose as the fungi themselves. 



60 Waksman and Skinner, 1926 (p. 190). 



61 Stoklasa, J. tTber die Wirkung des Stallmistes. Ztschr. landw. Versuchsw. 

 Oesterr., 10: 440. 1907; Fuhling's landw. Ztg., 56: 411. 1907. 



