INFLUENCE OF ENVIRONMENTAL CONDITIONS 



773 



By comparing the influence of manure with inorganic fertilizers, 

 Temple 19 found that the addition of sodium nitrate to the soil increased 

 the number of bacteria from 6,500,000 to 8,480,000; the addition of a 

 complete mineral fertilizer increased these numbers to 11,540,000, 

 while stable manure brought about an increase to 23,310,000, on the 

 average of several determinations. This increase continues over a 

 considerable period. However, when the manure was previously 

 sterilized, before adding it to the soil, the increase in the numbers of 

 bacteria was even greater than in the case of unsterilized manure. 

 Temple suggested, therefore, that the increase in the numbers of 

 bacteria as a result of addition of manure is due to the addition of the 

 organic matter (available energy) rather than to the actual introduction 



TABLE 87 



Influence of coto manure (10 tons per acre) upon the number of bacteria per gram of 



dry soil (1 gm. of manure contained 625,000,000 bacteria) 



of bacteria, as suggested by other investigators. A direct relationship 

 between the organic matter added to the soil and the bacterial count 

 was also observed. 20 The work of Charpentier and Barthel (p. 450) 

 on the decomposition of pure cellulose in the soil tends to confirm the 

 observations that the fertilizing effect of manure is due entirely to its 

 nitrogen and minerals and not to the bacteria introduced. No greater 

 increase in the numbers of bacteria from the addition of stable 

 manure with green manure to the soil was obtained than from the 



19 Temple, J. The influence of stall manure upon the bacterial flora of the 

 soil. Ga. Agr. Exp. Sta. Bui. 95. 1911; Centrbl. Bakt. II, 34: 204-223. 1912. 



20 Briscoe, C. F., and Harned, H. H. Bacteriological effects of green manure. 

 Miss. Agr. Exp. Sta. Bui. 168, 20 p. 1915. 



