FUNCTION 335 



The cellulose ferments also perform other direct functions in 

 the soil, as for instance, the liberating of plant food which is bound 

 up in plant residues. Heinze has very recently ascribed to bacterial 

 activities much of the benefits obtained from summer fallowing. 

 In quantitative studies he found them to be more numerous in 

 fallow soil than in cropped soil, and he thinks it to be due to their 

 activities in rendering the cellulose more suitable as a carbon 

 supply for the Azotobacter that causes the increase of soil nitrogen 

 in fallow land noted by a number of recent workers. One of the 

 more important problems of today in soil bacteriology is the rela- 

 tionship between this class of organisms and other important soil 

 organisms, especially the nitrifiers and the nitrogen fixers. 



REFERENCES. 



Lafar: Handbuch der Technischen Mykologie. 



McBeth: Studies on the Decomposition of Cellulose in Soils, Soil Science, i, 

 437-488. 



