LITERATURE 135 



nitrate under aerobic conditions, such a transformation is quite 

 completely inhibited under anaerobic conditions, and accumula- 

 tion of ammonia over a period of time may be greater in an anaero- 

 bic environment than where there is free access of oxygen. Under 

 aerobic conditions a great variety of organisms are active. Some 

 fungi may be as active under neutral as under acid conditions. 

 The bacteria and actinomyces are coniined to much narrower 

 ranges of reaction. 



At no time is all the nitrogen of the organic matter liberated 

 completely as ammonia, but the longer the period of decomposition 

 the more complete the reaction. The factors considered above are 

 of particular importance in determining the speed of mineralization 

 of nitrogen added to the soil in the various plant and animal 

 residues. 



LITERATURE 



1. BoNAZzi, A. The mineralization of atmospheric nitrogen by biological 



means. Proceedings of the Fourth International Soil Science Con- 

 ference. 1925. Section 3B, No. 8. 



2. Buchanan, R. E., and Fulmer, E. I. Physiology and biochemistry of 



bacteria. Volume 3, Chapter 16. The Williams & Wilkins Co. 

 Baltimore, 1930. 



3. Fred, E. B. The root-nodule bacteria of leguminous plants, in The 



newer knowledge of bacteriology and immunology, pp. 332-340. The 

 University of Chicago Press, 1928. 



4. GiOBEL, G. The relation of the soil nitrogen to nodule development and 



fi.xation of nitrogen by certain legumes. N. J. Agr. Exper. Sta. Bulle- 

 tin 436. 1926. pp. 1-125. 



5. Stephenson, M. Bacterial metaboHsm. Chapter 8. Longmans, Green 



& Co. London, 1930. 



6. Waksman, S. a. Principles of soil microbiology. Chapters 4 and 22. 



The Williams & Wilkins Co. Baltimore, 1927. 



