252 



INDEX 



B 

 Bacilli in soU, 28 

 Bacillus cellulosae dissolvens, 23 

 Bacillus megatherium, 22 

 Bacteria, abundance of, as index of 

 soil fertility, 236-237 

 decomposing cellulose, 82, 85-87 

 effects of partial sterilization on, 



224-229 

 of soil, 27-33 



abundance of, 56-58 



influence of manure on, 214, 

 216 

 activities of, 30-33 



influence of tillage on, 216-217 

 influence of reaction on cellulose 



decomposition by, 85-86 

 nitrogen fixing, 104-126 

 nodule, life cycle of, 115-117 

 numbers of, 46-47, 48, 52, 56-65 

 penetration of roots by, 201 

 Bacteriorrhiza, 200-201 

 Bacterium coli, in manure, 214 



in soil, 44 

 Bacterium radicicola, 25, 114, 125, 200 

 Bacteroids, 116 

 Balantiophorus elongatus, 40 

 Bases in soil, 17 

 Basidiomycetes, 34 

 Bodo caiidatus, 40 

 Bumillaria exilis, 37 

 Butyric acid, 163, 164 



C 



Carbohydrates, influence of, on am- 

 monia formation, 132-133 

 Carbon, assimilation in decomposition 

 of organic matter, 94-99, 133 

 changes during decomposition, 97- 



99 

 content of microbial cells, 94-95 

 effects of microbes on, 243-244 

 Carbon dioxide, action of, on min- 

 erals, 160 

 evolution of, 181 

 in atmosphere and plant growth, 



182-183 

 in soil, 158-161 



Carbon dioxide, in soil, influence of 

 partial sterilization on, 225- 

 226 

 liberation of, by microbes, 18-19 

 production of, in decomposition 

 processes, 80-81, 86, 90, 97- 

 101, 146, 157 

 in soil, 157 



as index of soU fertility, 237 

 Carbon-nitrogen ratio of soil organic 



matter, 99-101 

 Cellulose, 77, 78 



combination of, with lignin, 82 

 decomposition of, aerobic, 82-86, 

 89, 91 

 anaerobic, 85-87, 89 

 as index of soil fertility, 235 

 influence of, on formation of soil 

 humus, 87 

 on nitrogen assimilation by 



bacteria, 95-96 

 on numbers of fungi in soil, 83 

 influence of environmental con- 

 ditions on, 82, 84-86, 89 

 influence of manures on, 84 

 influence of moisture on organ- 

 isms causing, 88 

 influence of nitrogen on, 83, 84, 



86-87 

 influence of phosphorus on, 84-85 

 influence of reaction on, 83, 84 

 influence of soil conditions on, 87 

 products of, 86-87 

 occurrence in plants, 82 

 organisms decomposing, 82 

 Cellulose bacteria, thermophilic, 86 

 Cellulose-nitrogen ratio, 83-84 

 Chemical composition of soil, 5-8, 16 

 Chitin, decomposition of, 130 

 Chlamydomonas com?nunis, 38 

 Chlorophyceae, 37 

 Ciliates, 38 

 Citric acid, 163 



Climate, effect of, on chemical com- 

 position of soil, 6-8 

 influence of, on microbial devel- 

 opment, 63 

 Clostridium botulinus, 40 



