500 



Index 



201 ; lose effectiveness, 145 ; of dif- 

 ferent soils compared, 144, 201 ; 

 depth, 147, 165, 206; frequency of stir- 

 ring, 164. 



Soil moisture, advantages of abundant 

 supply, 9; mechanism of plant sup- 

 ply, 54; effect of subsoiling, 134; ef- 

 fect of fallowing, 153, 155, 162, 225; in 

 potato rows, 161; means of conserv- 

 ing, 131; conservation by tillage, 164; 

 influence of rolling, 166; loss through 

 mulches, 144, 201; best amount, 226. 



Soil ventilation, 419; need, 11; work of 

 carbonic acid, 419 ; influence of drain- 

 age, 418; part played by roots, 420, 

 421; influence of changing air tem- 

 perature and pressure, 420; may les- 

 sen denitrification, 420; may increase 

 nitrates, 420; may be too thorough, 

 421. 



Soil temperature, 248, 250, 425; in- 

 fluenced by drainage, 423 ; importance, 

 425; influence on germination, 425; 

 influence of cultivation, 427. 



Soil warmth, 425. 



Soil water, plant-food dissolved, 14 ; 

 amount of alkalies carried, 278; stag- 

 nation prevented by drainage, 416. 



South America, irrigation, 87. 



South Carolina, rice irrigation, 238, 

 266, 306, 369, 372. 



Spain, irrigation, 72, 238; duty of water, 

 211. 



Spill-box, 245. 



Spraying lawns, 393. 



Strawberries, irrigation, 110, 181, 384 ; 

 roots, 232; sub-irrigation, 398. 



Storer, F. H., 254, 275. 



Sub-irrigation, 396; of clover, 179 ; ob- 

 jections and difficulties in the way, 

 396, 397, 401 ; water-meadows, 401 ; 

 orchards and small fruits, 401 ; dan- 

 ger of clogging tile by roots, 401 ; 

 time required, 401; through tile 

 drains, 400 ; conditions necessary, 401 ; 

 an adjunct to drainage, 460. 



Subsoil, affects duty of water, 205. 



Subsoiling, 133 ; effects, 139 ; sugar 

 cane, irrigation, 214 ; duty of water, 

 215. 



Summer fallowing, 153, 154, 163. 



Sunlight, evaporation during, 44 ; action 

 in plant-feeding, 49; limited in close 

 planting, 183, 194. 



Surface drainage, 464 ; examples, 466 : 

 peat lands, 491. 



Surface tension, 57. 



Swamp lands, 273 ; area in United 

 States, 415 ; improved by drainage, 

 416; intercepting underflow, 459; in- 

 tercepting surface water, 461. 



Switzerland, irrigation, 74, 365. 



Target-rod, 470, 471. 



Temperature of soil, 248 ; subsoil 

 changed by rains and irrigation, 14, 

 248 ; reduced by close planting, 183 .- 

 favorable to sewage irrigation, 404. 



Temperature of water for irrigation, 

 250. 



Tidal irrigation, 238, 261, 306, 369, 373. 



Tigris, canals, 69. 



Tile, injury by frost, 442 ; for sub-irri- 

 gation, 398, 400; sire, 449, 452; laying, 

 484; in quicksand, 488. 



Tile-hook, 482. 



Tillage, extent to which it may replace 

 rain or irrigation, 117 ; most which 

 may be hoped for tillage, 120 ; inap- 

 plicable in some cases, 127 ; chiefly 

 saves early rains, 128; may do harm, 

 129 ; late plowing, 132 ; subsoiling, 

 133; earth mulches, 142, 164, 206; 

 mulches lose in effectiveness, 145 ; 

 harrowing and rolling, 146, 166; early 

 tillage important, 148 ; plow as a til- 

 lage tool, 149 ; intertillage, 157, 163 ; 

 frequency of tillage, 164, 205 ; depth, 

 165, 206 ; ridged and flat cultivation, 

 165 ; in rice fields, 370 ; after irriga- 

 tion, 381, 389 ; with orchard cultiva.- 

 tor, 38;. 



