426 



INDEX 



Density, with surface tension of 



solutions, 206 

 Deoxidation, 21 

 Deposits, eolial, 53 



glacial or ice-laid, chapter on, 



41 



Determination of humus, 156 

 Diabase, 7 



Dialysis and diffusion, colloids, crys- 

 talloids, 131 

 of colloids, 130 

 Diffusion, factor in aeration, 311 



temperature for, 298 

 Digestibility of feeds, 162 

 Diorite, 7 



Disintegration by plants, 19 

 by waves, 18 

 by wind, 18 

 of rocks, 11, 32 

 Distribution of alkali, vertical and 



horizontal, 281 

 of irrigation water, 268 

 Ditches, open drains, 226 

 Dobeneck, hygroscopic moisture in 

 relation to relative humidity, 

 196 



Dolomite, calcium magnesium car- 

 bonate, 5 

 Dorsey, C. W., reclamation of alkali 



land by underdrainage, 289 

 alkali at Maryland station, 290 

 Drain gages, 220 

 Drainage, chapter on, 222 



benefits of, aeration improved, 



223 



alkali, rise of, prevented, 226 

 decomposition and nitrifica- 

 tion increased, 225 

 erosion decreased, 226 

 granulation improved, 222 

 heaving reduced, 225 

 moisture, available, in- 

 creased, 222 

 stability increased, 222 

 temperature raised, 225 

 effect of, on germination and 



growth, 223 



on soil temperature, 301 

 from 8 feet of saturated sand, 



221 

 types of, open or ditches, 226 



tile, 228 



Drains, see Drainage 

 Drills, seeders, 337 

 Drumlins, 44 



formation of, 45 



Dry-farming, crops for alfalfa, 253 

 barley, 251 

 corn, 251 

 emmer, 252 

 kafir, 252 

 milo maize, 252 

 oats, 251 

 potatoes, 253 

 rye, 251 

 sorghum, 252 

 spelt, 252 

 wheat, 250 

 deep, medium-grained soil well 



adapted to, 243 

 Dry-land agriculture, chapter on, 



238 

 Dumont, effect alkaline carbonate on 



nitrate production, 321 

 Dunes, clay, sand, silt, 53 

 permanent or fixed, 55 

 wandering, migatory, 54 

 Dupr6, with Lynde, capillary pull, 



211 



osmosis in soils, 212 

 Dust and loess, physical analysis of, 



64 



storm, 54 

 volcanic, 65 

 Dynamiting of soils, 345 



Earth, composition of, 2 



dam for filling gullies, 371, 372 

 Earth's crust, elements of, 1 

 Earthworms, aid in soil formation, 



315 



effect of, on soil, 25 

 Eel-grass, 37 

 Elements of earth's crust, 1 



plant food, 390 



Electrical behavior of colloids, 133 

 Elutriator, method of physical analy- 

 sis, Schone, 124 

 churn, Hilgard's 126 

 centrifugal, Yoder's, 128 

 Eolial deposits, or wind-laid soils, 



53 



adobe, in part, 64, 65 

 loess, 60-64 

 sand, 53-64 

 volcanic dust, 65 



Eroded hill lands, yield from, 360 

 soil once forested, China, 359 

 Erosion, chapter on, 357 

 cause of, 



rainfall, character of, 359 

 texture and structure of soil, 

 358 



