528 



INDEX 



PAGE 



Storing water in soil, importance 



of depth 198 



Straw as litter in manure 367 



Straw mulches, in potato growing. 201 



Stream-formed soils 47 



Structure of soil, defined 88 



Structure, conditions affecting. . . . 103 



Affected by animal life 118 



Affected by carbonate of lime. .352 



Affected by caustic lime 352 



Affected by crop rotations 506 



Affects capillary water 151 



Affected by organic matter. . . .114 



Affected by rainfall 119 



Affected by soluble salts 116 



Affected by surface covering ... 1 19 



And moisture content 105 



Crumb 91 



Effect on capillary movement. .182 



Heat conductivity 459 



Percolation 167 



Tillage on 111,469 



Lime 116 



Nitrate of soda 118 



Structure, effect of plow on 469 



Affected by roots 13 



Granular 91 



Ideal aspects 88 



Influence of drainage on 240 



Modification of 104 



Puddled 90 



Relation to texture 88, 92 



Relation to soil air 432 



Relation to moisture 156 



Relation to porosity 88 



Structure, separate grain 89 



Sub-irrigation, natural 233 



Advantages and disadvantages . 234 



Method of artificial 234 



"Subsoil", defined 68 



Organic matter in 125 



Plows, operation of 218 



Plow, purpose of 477 



Plow, when to use 478 



Productiveness of arid and 



humid 69 



Subsoiling, aims of 218 



Conditions requiring 218 



Increases water capacity 219 



May be injurious 218 



Relation to sub-surface packing . 212 



Time to perform 212 



Substitution of bases in the soil . . . 297 



PAGE 



Substitution of one mineral nutri- 

 ent for another 280 



Packer 488 



Packing necessary in subsoiling . 220 



Sub-surface packing 212 



Sulfate of lime, effect on soil 354 



Sulfate of potash 341 



Sulfur, as plant-food element 3 



Sunshine distribution of in United 



States 452 



Relation to soil temperature 452, 453 

 Superphosphates, composition of. 338 



Fertilizers 337 



Manufacture of 337 



Supply of soil water 136 



Surface area, in field soils 83 



Calculation of 83 



Relation to absorption 103 



Relation to texture 82 



Surface covering, influence on struc- 

 ture 119 



Surface tension.and capillarityl58, 182 



Affected by 159, 173 



And plasticity 97 



Movement of water by 182 



Relation of fertilizers to 182 



Relation to granulation in tillagell2 

 Surface drains. See Open drains. 

 Swamp soil, organic matter in. . . . 125 

 Sweep, cultivators, efficiency of . .480 



Swine manure 370 



Symbiosis, fixation of nitrogen by .423 

 Systems of textural classification 71, 73 



Table of surface tensions 159 



Tankage 334 



Temperature affects, movement of 



moisture 1 73 



Of color on 456 



Percolation 168 



Surface tension 173 



Temperature of soil. <See, also, Heat. 



Affected by wind 461 



And air, monthly range 454 



At different depths 454 



Daily range of 453 



Effect of drainage on 463 



Effect of manure on 464 



Effect of moisture on 461 



Effect on chemical processes . . . .451 



Effect on conductivity 459 



Effect upon movement of soil air 441 

 Factors which determine 453 







