INDEX 



PAGE 



Absolute specific gravity jf soil ... 94 



Absorption by the soil ..... 297 



Causes of ... 299 



Effect of adsorption .301 



Effect of aluminum hydrate . . .300 



Effect of calcium carbonate 300 



Effect of ferric hydrate 300 



Effect of humus 300 



Effect of size of particle 299 



Effect of zeolites 299 



Influence in soil analysis 277 



Insolubility of absorbed sub- 

 stances 299 



Occlusion 301 



Relation to drainage 302 



Relation to productiveness 306 



Time required 297 



Absorption of nutrient salts 286 



Absorptive, physical 102 



Absorption properties of humus. . 128 

 Abundance of common minerals . . 8 

 Acidity of soil, effect of ammonium 



sulfate 326 



Effect of lime 349 



Effect on availability of fertiliz- 

 ers 360 



Effect on availability of phos- 

 phorous 361 



Effect on bacteria 360 



Effect on liberation of potas- 

 sium 360 



In relation to bacteria 401 



Acme harrow, efficiency of 484 



Adaptation of crops to soil, exam- 

 ples of 503 



Part in soil management, 465 



To soil, factors in 499 



To soil, philosophy 497 



To soil, lack of knowledge 501 



Adjustment of soil moisture 170 



Adobe soil, relation to wind forma- 

 tion 62 



Adsorption by the soil 301 



Effect on nitrates 301 



Relation to plant nutrition. . . .301 



PAGE 



yEolian rocks 11, 14 



yEolian soils, deposition of 60 



Composition of 63 



Relation to loess 60 



Aeration, effect on availability of 



fertilizers 359 



Effect of drainage on 242 



Effect of nitrification 416 



Agencies of rock decay 14 



Plants and animals 28 



Agricultural classes of soil 74, 77 



Air (oxygen) of soil, as factor in 



plant growth 1 



Circulation of, affects soil tem- 

 perature 461 



Air of soil, effect of on percolation . 167 



Air of the soil 432 



Analyses 434 



Composition 434 



Carbon dioxide in 438 



Effect of carbon dioxide produc- 

 tion on 435 



Effect of cropping on 447 



Effect of irrigation on 447 



Effect of manures on 444 



Effect of organic matter on. . . .433 

 Effect of roots on composition. .437 



Effect of soil moisture on 433 



Effect of structure 432 



Effect of texture 432 



Effect of tillage on 444 



Effect of underdrainage on. . . .445 



Escape of carbon dioxide 436 



Functions 437 



Modifying volume and move- 

 ment 443 



Movements 439 



Movement due to atmospheric 



pressure 440 



Movement due to gaseous dif- 

 fusion 439 



Movement due to temperature. 441 



Movement due to water 440 



Movement due to wind 443 



Oxidation 437 



GG 



(513) 



