886 



INDEX OF SUBJECTS 



Nitrification, 62, 527, 637, 836 

 as influenced by carbon-nitrogen 



ratio of soil, 509 

 methods of studying, 715 

 Nitrifying bacteria, numbers of, in 

 soil, 37, 38, 77 

 isolation of, from soil, 63, 68 

 limiting and optimum reaction of, 77 

 occurrence of, in soil, 67, 77 

 Nitrifying capacity of soil as index of 



soil fertility, 713,715-717 

 Nitrite formation, from inorganic and 

 organic substances, 527 

 in the reduction of nitrates, 298 

 Nitrite-forming bacteria, 59, 62, 151 

 Nitrite oxidation, mechanism of, 526 

 Nitrite utilization by actinomyces, 



298-299 

 Nitrobacter, 74, 75, 79, 100, 400, 637 



growth of, on organic media, 76 

 Nitrogen compounds, assimilation of, 

 by algae, 234 

 assimilation of, by bacteria, 368 

 as sources of energy for autotrophic 



bacteria, 62, 389 

 decomposition of, in presence of non- 

 nitrogenous, 505 

 decomposition of, in organic matter, 



705 

 in leachings, as influenced by plant 



residues, 706 

 in manure, 498 



influence of, on plant growth, 502 

 non-protein nitrogen, decomposition 



of, 485 

 utilization of by bacteria and fungi, 

 502 

 Nitrogen fixation, and respiration, 566 

 as influenced by partial steriliza- 

 tion of soil, 757 

 by algae, 105, 231 

 by algae, in symbiosis with Azoto- 



bacter, 120, 232 

 by anaerobic bacteria, 109, 179 

 by higher plants, 106 

 by mycorrhiza fungi, 281 

 by nodule bacteria, 103, 122-140 

 by soil fungi, 105, 207 



Nitrogen fixation, chemistry of pro- 

 cess, 572 

 chemical fixation in soil, 103 

 in nature, 103 

 in soil, 560 



influence of available nitrogen on, 575 

 influence of organic matter on, 579 

 non-symbiotic, 104, 111, 558 

 non-symbiotic, importance of in soil, 



585-588 

 symbiotic, 106, 122, 588 

 Nitrogen-fixing bacteria, 5, 27 

 aerobic, 59, 106, 112, 558 (see also 



Azotobacter) 

 anaerobic, 59, 106, 107, 166, 175, 

 558 (see also Bac. amylobacter 

 and Clostridium) 

 numbers of, in soil, 37, 38 

 symbiotic, 59 

 Nitrogen-fixing capacity of soil, 



729-734 

 Nitrogen gas, formation of in decom- 

 position of organic matter, 183 

 formation of, in nitrate reduction, 



183, 184, 550 

 losses of, in soil, 554 

 Nitrogen, oxides of, formation by bac- 

 teria, 178, 184, 549 

 transformation by microorganisms, 



504 

 transformation in the rotting of 



manure, 498 

 transformation in the decomposition 

 of organic matter in the soil, 500 

 Nitrogen utilization, by actinomyces, 

 298 

 by algae, 231 

 by fungi, 267 

 Nitrogenous substances, decomposi- 

 tion of, by fungi, 266 

 Nilromicrobium, 77 

 Nitrosococcus, 72, 73, 74, 79, 100 

 Nitrosomonads, 8 

 Nitrosomonas, 72, 79, 100, 400, 637 

 europea, 72 

 javanensis, 73, 95 

 Nitschia, 224, 227 

 Nocardia, 287, 288, 402 



