438 



INDEX 



Soils, compacted by tillage, 326 



conductivity of, effect on tem- 

 perature, 305 

 constituents, capillary lift of, 



212 



specific heat of, 299 

 cumulose, 27 



deep, medium -grained, well 

 adapted to dry farming, 243 

 definition of, 1 



effect of alkali on physical con- 

 dition of, 280 

 of color of, on growth, 303 

 on transpiration, 191 

 eolial, 53 



erosion, chapter on, 358 

 fertility, appendix I, 389 

 -forming minerals, 1 

 glacial, 41 

 gravelly, not well adapted to 



dry farming, 240 

 gravity-laid, 30 

 gullies filled with, 374 

 heat, loss of, by conduction 

 downward into soil, 29(5 

 by convection currents of 



air, 296 

 by evaporation of water, 



296 



by radiation, 295 

 sources of, 293 



chemical changes, 294 

 physical changes, 294 

 precipitation, 294 

 radiation, direct from sun, 



293 



"heavy," "light," defined, 134 

 humid, 75 

 hygroscopic capacity of, 194 



coefficient of, 196 

 Illinois, fertility in, 394 

 Kentucky, 393 

 lacustrine, 37 

 lime and magnesia in, 75 

 marine deposits, 36 

 material and its origin, chapter 



on, 1 



placing of, 27 



relative conductivity of, 306 

 methods of increasing moisture 



capacity of, 230 



mineral constituents of, chap- 

 ter on, 123 

 content of, 74 

 Missouri, 392 

 mulch, defined, 233 

 mulches, effectiveness of, 235 



Soils, odor of, 177 



organic constituents of, chap- 

 ter on, 142 



organisms, chapter on, 315 

 particles and their separation, 



123 



held together by organic mat- 

 ter, 151 

 surfaces of, in different soils, 



181 

 physical character of, changed 



by erosion, 360 

 properties of, chapter on, 175 

 plant food, supply in, 391 

 porosity of, 182-184 

 prairie, . 75 

 provinces, area surveyed to 



1915, 78 

 regions, area surveyed to 1915, 



78 

 residual, 27 



plant food in, 392 

 running together hinders aera- 

 tion, 313 

 samplers, 1 19 

 sampling of, 120 

 Sangamon, 49 

 sedimental, 33 



classes of, 36 



series, Bureau of Soils, 79-111 

 shrinkage of, 133, 135 

 soluble salts in, 74 

 specific heat of, 300 

 strata, distribution of organic 



matter in, 147 

 thickness of. 120 

 weight of, 120 

 stream-laid, 38 

 subsurface, 67 

 surface, 67 



survey by .bureau of Soils, chap- 

 ter on, 78 

 by Illinois Experiment S'ta- 



tion, chapter on, 1 12 

 methods of, 118 

 objects of, 117 

 surveys, 116 



temperature, chapter on, 293 

 conditions affecting, 298 

 absorption and radiation, 



302 



color, 303 

 conductivity, 306 

 drainage, 301 

 evaporation, 300 



