INDEX 



427 



Erosion, cause of, topography, effect 



of, 358 



vegetative covering, 359 

 checked by brush, 372 

 decreased by drainage, 226 

 by organic matter, 150 

 headwater, 372 

 in pasture, 370 

 kinds of, sheet, 361 



gullying, 369 

 of streams, 16 

 old-field in Mississippi, 370 

 organic matter lost by, 151 

 results of, color of soil changed, 



361 

 organic matter and nitrogen 



removed, 360 

 physical character of soil 



changed, 360 



sheet, methods of prevention and 

 reclamation, contour 

 seeding, 365 

 crops, protection by, 



361 

 deep contour plowing, 



364 

 limestone, application 



of, 361 



organic matter, in- 

 creasing. 363 

 reforesting, 369 

 residues, 363 

 terracing, 3(55 



tiling, 369 

 Eruptive rocks, 6 

 Esker, Adeline, 44 



material composing it, 45 

 formation of, 45 



Evaporation, effect of, on soil tem- 

 perature, 300 



factor in adaptability of a re- 

 gion to dry farming, 241 

 from a free-water surface and 



rainfall, 241 



large loss from, in dry farm- 

 ing, 243 



loss by, effect on transpira- 

 tion, 191 



of water, cools soil, 296 

 prevented by mulches, 232 

 rainfall and, Rothamsted, 211 

 rainfall and percolation. Hoth- 

 amsted, 220 

 retarding of, factor in cropping 



alkali land. 285 

 Everglades, Florida, 29 

 Exfoliated granite in California, 13 



Expansion, enormous, due to hydra- 



tion, 21 



due to oxidation, 21 

 of rocks, 13 



Expressing moisture content, ways 

 of, 191 



Fall plowing, 342 



Fallow, continuous vs. after, wheat 



yields, Montana, 248 

 Fallowing, loss of organic matter 



by, 153 

 Farm land, value per acre, 410 



property, value per acre, 411 

 Feeds, digestibility of, 162 

 Feldspars, 3 



composition of, 3 

 Fermentation in manure, factor m 



loss of organic matter, 164 

 Fertility in Illinois soils, 394-396 

 Films and waists of water about 



particles, 200 



thickness of, in soil column, 201 

 Fine sandy loams, 116 

 Fippin, E. O., with Lyon, T. L., sur- 

 face tension and density of cer- 

 tain solutions, 206 

 Fires, organic matter lost by, 152 

 Fischer, carlxm dioxide in rain and 



snow water, 20 



Flocculation, effect of ammonia, 

 lime, gypsum, sodium carlx>n- 

 ate on, 137 



or coagulation of clays, 137 

 Flooding orchards, basin system, '270 

 Florida everglades, 29 

 Flow of water, comparison l>etween 



computed and observed, 129 

 Food for bacteria, 319 

 Forl>es, R. H., vnlue of material car- 

 ried by Salt River. 262 

 Forest, being buried by sand dune, 55 



resurrected. 55 

 Fragmental deposits. 8 

 Freezing and boiling points, col- 

 loids, effect on, 131 

 and thawing. 14 



effect on water logged soil. 22.S 

 Furrow irrigation of potntoes. 271 



Geological classification of soils. 72 

 <!corgeson, influence of manure on 



soil temperature, 294 

 Germination and growth, effect of 



drainage on. 223 

 limit of alkali for. 284 

 temperature for. 296 



