INDEX 



385 



Soil, atmosphere— Continued 



respiration, 174 



winter and summer, 174 

 base exchange, 179-182 

 capacity, 180 

 classification 



by mature profiles, 155 



climatic, 155, 157-158, 160 



zonal, 157, 160 

 conservation, 338-341 



strip cropping and terraces, 340 

 defined, 144 

 development, 147 



and vegetation, 159-161 



biological activity, 146 



moisture, 159 



temperature relationships, 159 

 flora 



organisms free in soil, 197-198 



symbiotic fungi and bacteria, 

 194-196 

 formation, 144-147 



agents, 144 



carbonation, 145 



oxidation and hydration, 145 



processes, 144 

 horizons, 146, 147 



and root distribution, 147 

 litter, 153 



major components, 148 

 organic content, and microorgan- 

 isms, 146, 153-154 

 origin, 153-154 



fermentation (F) layer, 154 



humus (H) layer, 154 



litter (L) layer, 153 

 organisms 



and acidity, 178 



growth inhibiting substances, 182 

 origin 



cumulose soils, 148-149 



residual soils, 148 

 sedentary soils, 148 



transported soils, 152 

 plant relationships, 148 

 point cones, 173-174 

 porosity, 177 

 profile, 146, 147-148 



and weathering, 147 



development of, 147 



processes of development 

 calcification, 156-157 

 laterization, 156-157 

 podsolization, 155-156 

 salinity, 184-185 



sampler, 167 

 samples, in place, 167 

 solution, 171 

 source of nutrients, 153 

 structure, 153 



aggregation, 153 



determines air capacity, 175 



effect of colloids, 153 



shrinkage on drying, 153 



single grain, 153 

 temperature, 122, 123 



daily and seasonal lag, 122 



extremes at surface, 119 



forest litter, 127 



germination, 126 



modified by cover, 126 



relation to atmosphere, 122 



seedling survival, 126 



water content, 171 



water relations, 126, 171 

 texture, 152-153 



a basis of classification, 1 52 



and naming of soils, 153 



and shrinkage, 153 



mechanical analysis, 152 

 total pore volume, 177 

 transported 



alluvial, 149-150 



by ice, 151 



colluvial, 150 



colluvial cones, 150 



dunes, 111-115, 149-150 



glacial moraine, 151 



loess, 112-113, 149 

 types and climate, 157-159 

 types, climatic, 155, 157 

 variations, local, 148-154 



in origin, 148-154 



structure, 148 



texture, 148 

 variations, regional, 154-161 



relation to climate, 154-155 

 water, 161-174 



and competition, 30 



and temperature, 126 



availability to plants, 170-171 



classification, 161-162 



constants, 166-171 



capillary capacity, 168 

 capillary potential, 164 

 field capacity, 164, 168 

 hygroscopic coefficient, 167 

 maximum water holding 



capacity, 168 

 moisture equivalent, 169 



