530 



INDEX 



PAGE 



Volume change of humus 128 



Of soil air, methods for modify- 

 ing 443 



Of water held by soils 154 



Weight, table of 96 



Wagner, on effect of manure on soil 



temperature 464 



Warington, effect of lime on clay 



soil 117 



Figures on water used by plants . 133 

 Quotes figures on heat conduc- 

 tivity 459 



.Quotes figures on specific heat. .456 

 Quotes on adequate soil moist- 

 ure 156 



Quotes, on shrinkage 98 



Shrinkage of clay and humus. . . 128 



Specific gravity of humus 128 



Suggestions on structure 103 



Warm soils, meaning of 462 



Water, amount of used by plants . 133 



Amount in soil 135 



As agency of rock decay 21 



As agency of soil transportation . 45 



Available in field soils 157 



Capillary movement of 169 



Capacity, maximum 161 



Capacity of humus 130 



Capacity of soil 136 



Capacity of soil, effect of texture 



and structure on 216 



Capacity of soil increased by 



subsoiling 219 



Capacity of soil, influence of 



drainage on ' 241 



Capacity of soil, means of increas- 

 ing 216 



Carrying power 24 



Causes expansion of soil 162 



Character of soils deposited by. 46 

 Chemical action of in rock decay 21 

 Content of soil, effect on temper- 

 ature 461 



Content, statement of 136 



Content of soil, relation to crops .155 

 Composition of soils deposited 



by 49,50,51,52,53 



Critical content 155 



Division of soils deposited by . . . 46 



Erosion by 494 



Extract of soil 276 



Film 146 



PAGE 



Water, films and checking of soil . 98 



Films and structure 105 



Forms of 141 



Function of in plants 133 



Gravitational form 160 



Increased loss through rainfall . 198 



In soil, availability 141 



In soil, density of 290 



In soil, means of decreasing 238 



In soil, effect on movement of 



air 440 



Lack of, often controls crop 



yields 197 



Loss of from soil 164 



Material transported in chief 



rivers 26 



Maximum content 155 



Minimum content 155 



Mechanical action of in rock 



decay 24 



Movement of in soil 165 



Soil as reservoir 133 



Soil supply dependent on 136 



Solvent action 21 



Sorting power 27 



Supply of 136 



Used by different crops 185 



Volume of, held 154 



Way, experiments with soil absorp- 

 tion 298 



Weed, defined 489 



Control of, principles 490 



Deplete soil moisture 195 



Early and late tillage to kill. . . .491 



How, injurious 490 



Implements useful to kill 492 



Relation to crop rotation 508 



Removal of saves water 216 



Special methods of control 492 



Weeders, type of cultivator 483 



Weight of soil 94 



Weight of soil, per cubic foot 96 



Per acre-foot 96 



Weight of organic matter in soil . . 128 



Weight of peat and muck 128 



Wet soil, organic matter in 125 



White alkali , 309 



Whitney and Hosmer, soil moist- 

 ure 157 



Suggestions on structure 103 



Surface tension of solutions. . . . 159 

 Wind-blown material, character- 

 istic of 18 



