INDEX 



437 



Sand dunes, held by trailing wild 



bean, 60 

 vegetation, 57 



movement checked by fences, 58 

 porosity of different grades, 183 

 Sands, 110 



and sandv loams, properties 



of, 139 * 

 radiation ratio of different 



colors of, 295 

 temperature of, effect of color 



on, 302 

 Sandstones, 8 

 Sandy loams, 116 

 Sangamon interglacial stage, 47 



soil, 40 

 Schlpsing, relation, nitrates formed 



to oxygen, 320 

 Schone's elutriator method, physical 



analysis, 124 

 Schreiner, O.,- and Brown, E. K., 



progress of hurnification, 14(5 

 Sedentary formations, 27 

 Sediment carried in suspension by 



rivers, 35 



Seditnental soils, 33 

 classes of. 36 



Sedimentary, fragmental, 8 

 Seed, acclimated, necessary in dry 



fanning, 255 

 bed, preparation of, for corn, 



348 



for oats, 349 

 for wheat, 346 

 Seeders, 337 

 Seeding, different methods of, yield 



wheat on dry land, 254 

 on dry land. 254 

 rate per acre, Colorado, 255 

 Shaler, wave action, Capo Ann. 



Massachusetts, 18 

 Shales, 8 



Shantz, H. L., see Briggs 

 Shape of particles, 178 

 Shrinkage, affected by colloids, 1 32 

 cracks, 1 36 



effect of. on percolation. 21!> 

 physical composition of, 



135 

 of soils, 135 



different, types of soil, 133 

 Sieve method, physical analysis, 124 

 Silica, 2 

 Silt and silt loams, properties of, 



138 

 dunes, 53 



Silt loams, 115 

 Sink holes, 22 



in cave region, 24 



ponds, produced when outlet 



is clogged, 24 

 Size of soil particles, effect of, on 



capillarity, 201 



Slope of land, effect of, on soil tem- 

 peratures, 305 

 Snyder, loss of organic matter in 



forest fires, 152 

 nitrogen in humus from vari- 

 ous materials, 147 

 Sodium nitrate, 399 

 Soil soils 



air and aeration, chapter on, 



309 



carlxm dioxide in, 20 

 composition of, 310 

 alluvial, 38 

 amount of air in, 309 



of organic matter in, 142 

 and subsoil, chapter on, 67 

 are they inexhaustible? 289 

 arid, 74 

 auger, 119 



Bureau of, classification, chap- 

 ter on, 78 

 earried in suspension hv rivers, 



35 

 capillary or moisture-holding 



capacitv of, 209 

 pull of, 211 



character of, factor in its adapt- 

 ability to dry farming, 241 

 Chernozem, roots and humus in, 



144 



class, defined, "!> 

 classes in Illinois, 112 

 clay loams, 1 1 ."> 

 clays, 114 

 gravels. 11(5 

 gravelly loams. 116 

 loams. 1 1 .'> 

 mucks. 114 

 peats, 11(5 

 peaty loams. 116 

 sands, 1 1 6 

 sandy loams, 116 



fine, 11(5 

 silt loams, 115 



classification of. chapter on. 72 

 colloids in. 132 

 colluvial. 30 

 color of. 17(5 



effect on time of germination. 

 304 



