INFLUENCE OF ENVIRONMENTAL CONDITIONS 



797 



crop, such as wheat, rye, or timothy; this is particularly true of soils 

 rich in organic matter, and may be due to the more frequent cultivation 

 of the soil, on which the former crops are grown. An alfalfa or clover soil 

 kept fallow for two years was found 118 to nitrify dried blood more 

 rapidly than a timothy soil similarly treated. McBeth and Smith 119 



TABLE 93 

 Effect of buckwheat and of field peas upon the oxidation processes in a 



loam soil 



concluded that the nitrifying power of a cropped and irrigated soil 

 was higher than that of one which was not cropped. There was no 



118 Lyon, T. L., and Bizzell, J. A. The influence of alfalfa and timothy on the 

 production of nitrates in soils. Centrbl. Bakt. II, 37: 161-167. 1913. 



119 McBeth, I. G., and Smith, N. R. The influence of irrigation and crop 

 production on soil nitrification. Centrbl. Bakt. II, 40: 24-51. 1914. 



