762 



INDEX 



Root development, effect of drainage, 



631. 



Root excretions, 136. 

 Roots, effect on colloids, 411. 



effect of phosphorus, 550. 



effect on soil ventilation, 488. 



entrance into tile, 642. 



extent of surface, 412. 



nodules on, 458. 



of plants, distribution, 81. 



of plants and humus, 127. 



of plants under dry-farming, 717. 



of plants in soil, 424. 



oxidizing enzymes in, 407. 



solvent action, 405. 

 Rotation and green manure, 625. 



of crops and maintenance of humus, 

 152. 



of crops and manure, 615. 



of crops, remedy for soil diseases, 



425. 



Rothamsted, composition of drainage 

 water, 370. 



drain gauges, 266. 



losses of nitrogen, 500. 

 Run-off, losses from, 265. 



Salt, as amendment, 543. 

 Sampling soil in the field, 731. 

 Sand, 99. 

 Sand dunes, 63. 

 Sandstone, 6, 8. 



Sanitation of soil, effect of drainage, 633. 

 Sanitation of soil and toxic material, 137. 

 Saturated soil, 201. 

 Sawdust as litter, 603. 

 Schist, 6. 



Scraping, correction for alkali, 401. 

 Second-food of water, defined, 706. 

 Sediment in water, effect on erosion, 637. 

 Sedimentary, soil-forming rocks, 6. 

 Seeding machines as cultivators, 678. 

 Seepage, extent and prevention in irri- 

 gation, 694. 



Selective absorption, 362. 

 Selective absorption by colloids, 165. 

 Separates, mineralogical character, 99. 

 Separates, physical character of, 98. 

 Separates of soil, 84. 

 Series, the, in soil classification, 722. 

 Series of soil, named, 725. 

 Serpentine, 9. 

 Sewage irrigation, 711. 

 Sewage-sick soil, 474. 

 Shading and moisture loss, 287. 

 Shale, 6. 



Sheep manure, composition, 584. 



Shelters and moisture control, 285. 



Siderite, 9. 



Silica in soil separates, 102. 



Silicates, absorption by, 360. 



Silicates, influence on absorption, 357. 



Silicon, 6. 



Silt, character of separate, 98. 



Silt-basins, in drains, 656. 



Silvinit, potassium salt, 523. 



Single-grain structure, 110. 



Size of colloidal particles, 154. 



Size of soil particles, 95. 



Size of the drains, 650, 654. 



Slate, 6. 



Slag phosphate, 513. 



Slope and temperature, 317. 



Slime molds in soil, 425. 



Snow, effect on soil temperature, 306. 



Sod, effect on nitrification, 452. 



Sodium, 6. 



Sodium compounds, as fertilizer, 544. 



Sodium nitrate, as plant food, 498. 



Soil amendments, 534. 



best suited for dry-farming, 716. 



classification, factors used, 720. 



composition, general, 2. 



defined, 1. 



organic matter, 126. 



organisms, 421. 



sampling in the field, 731. 



solution in situ, 342. 



solution and plant growth, 347. 



survey, accuracy and detail, 733. 



survey, equipment for, 726. 



surveys, extent, 737. 



survey map, 736. 



survey report, 735. 



survey, its uses, 739. 



survey, principles of classification, 

 718. 



type, name, 725. 

 Soil and subsoil, arid and humid regions, 



82. 



Soil and subsoil, defined, 79. 

 Soil-forming minerals, 8. 

 Soil-forming rocks, 6. 

 Soil mulch versus dust mulch, 275. 

 Sol, colloidal condition, 159. 

 Soldate, module, 707. 

 Solid manure compared with liquid, 585. 

 Solubility of rocks in sodium carbonate, 

 26. 



of soil and texture, 331. 



of the soil, 327. 

 Solution and soil formation, 21. 



