INDEX 



255 



M 



Magnesium in soil, 18 

 Manure, animal, composition of, 

 209-212 

 decomposition of, 209-216 

 influence of, on soil microbes, 209, 



214-216 

 losses of nitrogen from, 213-214 

 microbes in, 209-210, 214 

 artificial, 216 

 green, influence of, on soil microbes, 



206-208, 214 

 influence of, on cellulose decompo- 

 sition, 84 

 preservation of, 143, 151 

 Mechanical analysis of soil, 6 

 Methane, decomposition of, 90 

 from cellulose decomposition, 86 

 from sugar decomposition, 80 

 Microbes, activities of, 21-42 

 importance of, in soil, 21-23, 



242-250 

 influence of organic matter on, 



204-216, 219 

 modification of, 203-241 

 nature of, 23-25 

 role of, in plant growth, 13 

 in soU, 19 



in supplying nitrogen to plants, 

 103 

 transformation of nitrogen l)y, 

 102-153 

 Microbial activities in soils, 243 

 correlation of, with soil fertility, 

 234-240 

 Microbial cells, carbon content of, 94- 

 95 

 decomposition of, 97 

 nitrogen content of, 94-95 

 Microbial population, similarities to 



human population, 250 

 Microscopic methods for the study of 



microbes, 24, 50-52, 57 

 Mineral assimilation by microorgan- 

 isms, 167 

 Mineral composition of soil, 4-5 

 Mineral elements as sources of energy, 

 155-156 



Mineral substances, transformation 



of, in soil, 154-180 

 Mineralization of organic matter, 



243-245 

 Moisture, influence of, on carbon 

 dioxide in soil, 160 

 on nitrification, 143-144 

 on numbers of soil microbes, 61- 



63 

 on organisms decomposing cel- 

 lulose, 88 

 Molds, 33 



Mononchus papillatus, 42 

 Mucor, 33, 34 



Mull, formation of, 205-206 

 Mull soils, nitrification in, 139 



organisms in, 139 

 Mushroom fungi, 34 

 Mycorrhiza, 196-200, 205 

 fungi, nitrogen fixation by, 200 

 parasitic action of, 200 



N 



Navicula terricola, 38 

 Nematodes in soil, 39 

 Nitrate, avenues of loss from sod, 

 147-148 

 formation, 136-146 

 influence of, on cellulose decom- 

 position, 87 

 on nitrogen fixation, 110, 120-124 

 production of, in decomposition 



processes, 93, 146 

 products of reduction of, 147-148 

 reduction, 145-152, 156 

 mechanism of, 147-149 

 organisms concerned in, 148 

 Nitre spots, 141 

 Nitrification, 136-146 

 bacteria causing, 136-140 

 factors affecting, 136-145 

 in manures, 143 

 in soil, influence of desiccation on, 



144 

 index of soil fertility, 235-236 

 influence of, on plant growth, 139 

 on soil reaction, 142 



