450 



PRINCIPLES OF SOIL MICROBIOLOGY 



addition of lime. Using C() 2 evolution as an index of decomposition 

 of organic matter, Potter and Snyder 71 found that CaC0 3 accelerates 

 the rate of decomposition of the organic matter present in the soil or 

 added in the form of stable manure (10 to 50 tons per acre). Similar 

 results were previously obtained by Lemmermann and associates. 72 



To stimulate cellulose decomposition in the soil, it may be sufficient 

 to add the proper nutrients, such as phosphoric acid or nitrogen sub- 

 stances. Charpentier 7 * found that the addition of 2 per cent of cow or 

 horse manure will greatly stimulate cellulose-decomposition in the soil. 

 The influence of the manure depends on the content of nutrients in the 

 manure and in the soil. With a sufficient amount of moisture and a fav- 

 orable reaction, the action of the manure is greater with a higher content 



Cei'ivlo&e 

 i> 



9.9 



O.t 



V 



3.--- 



■■*--"|.1»w^« 



1% Cellulose 



„ _ ., 27. stable manure 



. . — ♦''0.015?'. ammomium sulfate 



^-"-3 



ZhO 



360 390 



Fig. 25. Influence of nitrogen source upon the decomposition of cellulose in the 

 soil (after Charpentier). 



of nutrients in the manure and a lower content in the soil. The greater 

 the moisture content of the soil, the quicker will the cellulose be de- 

 composed. Cellulose decomposition is active both in acid and alka- 

 line soils, and lime merely plays the part of a regulator of soil reaction. 

 The addition of equal amounts of nitrogen in the form of ammonium 

 sulfate and cow manure brings about an equal stimulation of cellulose 



71 Potter, R. S., and Snyder, R. S. Carbon dioxide production in soils and 

 carbon and nitrogen changes in soils variously treated. Iowa Agr. Exp. Sta. 

 Res. Bui. 39: 255-309. 1917. 



72 Lemmermann, O., Aso, K., Fischer, H., and Fresenius, L. Untersuchungen 

 liber die Zersetzung der Kohlenstoffverbindungen verschiedener organischer 

 Substanzen im Boden, speziell unter dem Einfluss von Kalk. Landw. Jahrb., 

 41: 217-256. 1911. 



73 Charpentier, 1921 (p. 431). 



