INDEX 



493 



Sediments, cultural treatment of, 103. 



effect on crop yields, 104. 

 Seelhorst, 157. 



Seepage. See also Over^irrigation and 

 Alkali. 



from Indian canals, 341. 



from reservoirs and canals, 371. 



from over-irrigation, 373. 



arid vs. humid, 375. 



lined with ditches against, 376. 



drainage against, 381. 



economical use of water against, 381. 



and alkali. 384. 

 Selina, Ala., 407. 

 Sevier River, 375. 

 Sewage, value in irrigation, 414. 



use of, 415. 



Shade, effect on evaporation, 47. 

 Shad-scale, 397. 

 Shantz, 14, 126, 156. 

 Shaw, 239. 

 Showers, 59. 



Silting, as ditch-lining, 378. 

 Slosson, 390. 



Small fruits, under irrigation, 326. 

 Smith, 329, 405. 

 Smythe, 7, 484. 

 Snake River, 91. 

 Snow. See also Rain. 



loss by thawing, 41. 

 Society under irrigation, 476. 

 Soil, size of particles, 9. 



composition, 9. 



surface of particles, 10. 



moisture film of, 11. 



relation of particle and film, 12. 



hygroscopic coefficient, 13. 



wilting coefficient, 14. 



lento-capillary point, 16. 



maximum capillary capacity, 17. 



fill water in, 17. 



as water reservoir, 21. 



capacity for water of different, 22. 



unsaturated under irrigation, 22. 



field capacity of moisture, 29. 



hardpan in, 30. 



gravel in, 34. 



quantity water stored in, 35. 



best for irrigation, 35. 



absorption of water by, 38. 



effect of evaporation, 47. 



self-mulching, 52. 



fertility and cultivation, 59. 



contraction of, 64. 



changes due to water, 64. 



cohesion of particles, 65. 



volume change, 67. 



Soil, cracking of, 68. 



effect of water on top, 69. 



natural packing of, 70. 



successive wetting and drying, 70. 



temperature, 71. 



arid and humid contrasted, 73. 



continuous solubility, 74. ' 



absorption by, 76. 



composition of drainage water from, 

 78. 



depth of arid, 82. 



plant-food added by water, 93. 



washing of, 95. 



seasonal washing of, 98. 



suspended matter added by irriga 

 tion, 100. 



suspended matter from surface, 100. 



composition of river sediment, 101. 



physical effect of sediments, 102. 



cultural treatment of sediments, 103. 



water and soil life, 104. 



effect of sediments on crop yields, 104. 



effect of soil depth on water use, 116. 



effect of composition on water use, 

 117, 118. 



effect on water-cost, 137. 



storage of water in, 236. 

 Soil fertility and cultivation, 59. 

 Soil moisture, 8. 



See also Evaporation, Soil, Water, 

 Water-film, and Moisture-film. 



attraction of near bodies, 8. 



film of, 11. 



relation of particle and film, 12. 



hygroscopic coefficient, 13. 



wilting coefficient, 14. 



lento-capillary point, 16. 



maximum capillary capacity, 17. 



free water, 17. 



summary, 19. 



soil as reservoir, 21. 



capacity of different soils, 22. 



unsaturated soils under irrigation, 22. 



movement of, 23. 



distribution of, 25. 



field capacity, 29. 



effect of hardpan, 30. 



distribution in furrow irrigation, 30. 



effect of water table, 34. 



effect of gravel, 34. 



quantity water stored, 35. 



absorption by soils, 38. 



saving by cultivation, 40. 



how disposed of, 40. 



upward movement, 42. 



and evaporation, 43. 



contraction of film, 64. 



