4.98 



Index 



Park irrigation, 391. 



Peas, water used, 46. 



Peat lands, 491; warping, 262. 



Percolation of water, 225 ; through 

 sand, 113, 205; on duty of water, 203; 

 through shrinkage cracks, 227 ; into 

 tile, 446; loss, 330; rate from tile, 400. 



Perels, E., duty of water, 203, 212. 



Persian wheel, 325, 328. 



Peru, irrigation, 71. 



Phoenician irrigation, 69. [299. 



Pipe line, Redlands, 296; redwood, 298, 



Pipes for lawns, 394. 



PJagniol, salt in soils, 275. 



Plant breathing, 47. 



Plant feeding, 52, 57. 



Plant-food, 14, 15, 93, 252, 259; developed 

 by tillage, 149; effect of fallowing, 

 154; in alkali salts, 280, 285. 



Plant-house experiments, 18, 35, 43; 

 yields, 25, 41. 



Plowing, fall, 131: plowing under green 

 manure, 151; to form check ridges, 

 346. 



Plow, for producing mulch, 149 ; for 

 producing distributing furrows, 340, 

 342. [260. 



Po, irrigation, 72; sediment in water, 



Potatoes, irrigation, 28, 32, 35, 172, 353, 

 357, 413; water used, 30, 37, 46, 174, 

 237; yields, 110, 357; advantages of 

 irrigation in humid climates, 172 ; 

 watering alternate rows, 354, 357 ; 

 distance between rows, 357; moisture 

 in rows, 161, 200; duty of water, 215; 

 number of waterings, 237, 356. 



Press drill, 167. 



Puddling of soils, principles governing, 

 334. 



Pumping, with windmill, 313, 316; with 

 engines, 324; cost, 324, 326; for cran- 

 berries, 368; for drainage, 463. 



Pumps, with windmill, 316, 319; with 

 engines, 324, 326, 393; with water 

 wheels, 76, 306, 308, 309; with horse 

 power, 325. 



Quicksand, 488. 



Rainfall, in arid and semi -arid climates, 

 4, 6, 99, 101; timely, 10; of irrigated 

 countries, 89; in Kansas, 103; fre- 

 quency in Wisconsin, 108 ; like 

 amounts not equally effective, 101, 

 115, 204 ; relation to yield, 109, 125 ; 

 conditions modifying effectiveness, 

 110; in United States, 123; in eastern 

 United States, 124; amount needed in 

 humid regions, 121; of growing sea- 

 son, 124 ; distribution in time un- 

 favorable to maximum yields, 125; ' 

 early rains saved by tillage, 128; af- 

 fects duty of water, 204; in Colorado, 

 236; in India, 291. 



Ramming engine, 310. 



Rape, irrigation, 359. 



Raspberries, roots, 231; irrigation, 383; 

 sub-irrigation, 398. 



Read, T. M., solids in river waters, 253. 



Redlands, Cal., irrigation systems, 296. 



Red rice, 371. 



Reservoir, distributing, 297; construc- 

 tion, 320; sluice, 321; circular, 3^2; 

 seepage and evaporation, 323; capac- 

 ities, 323; for cranberries, 367; use in 

 drainage, 464. 



Rice, irrigation, 368; in Italy, 210; in 

 Egypt, 211; South Carolina, 238, 266, 

 306, 369, 372; duty of water, 217; fre- 

 quency of irrigation, 238 ; cultiva- 

 tion, 370; red rice, 371; upland, 373. 



Ridge cultivation, 165. 



Rio Grande, analyses of water, 253, 259. 



Road grader, 350. 



Rolling in relation to soil moisture, 166; 

 cause of loss of moisture, 167. 



Roman canals, 70. 



Root cap, 64. 



Root hairs, 55; relation to soil grains, 

 55; acid reaction, 59. 



Roots, depth of penetration in arid 

 soils, 6, 229; shallow in undrained 

 soil, 13; function, 55; absorbing sur- 



