INDEX OF SUBJECT MATTER 



587 



Structure of soil, effect on capillary 

 capacity, 164. 



effect on capillary movement, 174. 



effect on gravity water, 176. 



effect on heat conductivity, 236. 



ideal condition, 88. 



influence on optimum water, 201. 



nature of, 87. 



summary of, 149. 



types of, 139. 

 Substitutions of bases in soils, 270. 

 Sulfate sulfur as a fertilizer, 468. 

 Sulfofication, effect of lime on, 405. 



factors influencing, 405. 



influence on carbon dioxide produc- 

 tion, 255. 



determination of, 405. 



reactions of, 403. 



relation of to mineral cycle, 408. 

 Sulfur, amount added to soil in precipi- 

 tation, 469. 



amount in soils, 13. 



as a fertilizer, 467. 



experiments with as a fertilizer, 

 467. 



forms of in soil, 11. 



how lost from soil, 404. 



importance of in soil fertility, 470. 



loss of from Cornell soils, 307, 404. 



loss of from soil, 555. 



natural addition to soil, 557. 



oxidation of in soils, 403. 



possible deficiency in arable soils, 

 468. 



pounds removed by various crops, 

 468. 



sources of in soils, 403. 



use in composting, 406. 



use of as a sulfate, 468. 

 Sulfur composts, 406. 

 Sulfur cycle of soil, losses of sulfur from, 

 404. 



sources of sulfur, 403. 



sulfofication, 403. 

 Sulfurous acid, relation to mineral cycle, 



408. 

 Superfluous water, 198. 

 Surface of soil particles, calculation of, 

 97. 



importance of, 97. 

 Surface tension, defined, 160. 



effect on capillarity, 170. 



Surface tension, force of, 160. 



relation to capillary movement, 169. 

 Synergism, relation of to plant absorp- 

 tion, 300. 



relation of to soil acidity, 349. 



nature of, 349. 

 Systems of applying fertilizers, 496. 



Tankage changes in soil, 445. 



character of, 445. 



composition of, 445. 



source of, 445. 

 Temperature of soil, control of, 244. 



data of, 243. 



effect of change on soil air, 259. 



effect on capillary capacity, 163. 



effect on gravity water, 176. 



importance in soil formation, 21. 



influence of decay on, 239. 



influence of slope, 230. 



influence on bacteria, 394. 



influence on hygroscopic coefficient, 

 158. 



influence on nitrification, 420. 



variations of, 242. 

 Temperatures for crop growth, 224. 



for germination of seeds, 224. 

 Terracing, 205. 

 Texture of soil, definition of, 66. 



effect on absorption, 267. 



effect on capillary capacity, 164. 



effect on capillary movement, 173. 



effect on gravity water, 176. 



effect on heat conduction, 236. 



effect on specific heat, 232. 



influence on moisture equivalent, 

 168. 

 Thermal movement of soil water, na- 

 ture of, 182. 



relation to evaporation, 182. 

 Tile drains, depth and interval of, 214. 



effective grade for, 214. 



functions of, 212. 



outlets of, 214. 



size of tile, 213. 



study of drainage water from, 180. 



systems, 212. 



table for determination of size, 214. 

 Tillage, influence on granulation, 144. 



influence on soil solution, 286. 



killing of weeds by, 219. 

 Tilth of the soil, defined, 149. 



