INDEX 



439 



Precipitation, see Rainfall. 



Problems, of dry-farming, 6. 



Protein, in plants, 266 ; acquired 

 early by plants, 274 ; function 

 of, 264 ; more protein in dry-farm 

 crops, 269. 



Puddling, to be avoided, 159. 



Pumping, area irrigated from pump- 

 ing, 341 ; crop possibilities of 

 small plant in Arizona, 348 ; 

 water for dry-farms, 341 ; by 

 windmills, 341 ; cost of, in Ari- 

 zona, 344 ; cost of pumping in 

 California, 344 ; cost of pumping 

 in Kansas, 344 ; cost of, in New 

 Mexico, 343. 



Quality, valuation of dry-farm 

 crops, 257 ; on basis of water 

 content, 263. 



Rabbit-brush, 80. 



Railroads, and dry-farming, 363, 

 370. 



Rainfall, see also Natural Precipita- 

 tion, Winter Precipitation; rec- 

 ords insufficient in dry-farm 

 territory, 28 ; distribution over 

 earth-surface, 33 ; types of 

 distribution, 38-40 ; distribution 

 less important, 130 ; in spring or 

 summer causes loss of soil-water, 

 130, 160 : average does not 

 change, 400 ; chief factor in de- 

 termining aridity, 25 ; over one 

 acre in pounds, 19 ; and native 

 vegetation, 79 ; how disposed of, 

 97; depth of penetration, 114 

 downward movement in soil, 60 

 amount stored in soils, 114-115 

 effect of small rains on soil- 

 moisture, 113; importance of 

 moist subsoil in storm, 116; 

 proportion stored in Great Plains 

 soils, 122 ; amount stored in Utah 

 soils, 121 ; and plant growth, 

 261 ; crop-producing power of. 



18, 20 ; limits for dry-farming, 

 1 , 22 ; dry-farming with less 

 than 10 inches, 357, 385; and 

 amount to sow, 222 ; and fall 

 sowing, 216; irrigation supple- 

 mentary only to, 345 ; stored in 

 cisterns, 336. 



Reclamation Service, United States, 

 on area of desert land, 29. 



Record, continuous record of Barnes 

 farm, 403 ; continuous record of 

 Indian Head Station, 406. 



Red chaff wheat, 240. 



Red clover, pounds water for one 

 pound, 14. 



Red Fife wheat, 237. 



Red Russian wheat, 240. 



Relative Humidity, defined, 135 ; 

 over dry-farm territory, 46 ; 

 effects of, in New York and Salt 

 Lake City, 135 ; influence upon 

 transpiration, 176. 



Reservoirs, for flood water, 334 ; 

 building, 337. 



Rio Grande Basin, status of dry- 

 farming in, 388. 



Rocks, crystalline rocks and clay 

 soils, 57. 



Rocky Mountaiwi, description of the, 

 35. 



Roller, use of, on crop, 226, 227, 

 315. 



Root-hairs, organs of absorption, 

 167 ; immersion in soil-water, 

 168. 



Roots, functions of, 81 ; kinds of, 

 82 ; taproot, 83 ; Hbrous, 83 ; 

 systems, 81; extent of, 84; 

 weight of, 84, 85 ; depth of pene- 

 tration, 86 ; direction of develop- 

 ment, 89 ; development under 

 arid conditions, 88 ; develop- 

 ment under irrigation, 90 ; sys- 

 tems in arid vs. humid climates, 

 92 ; conditions of deep rooting, 

 93 ; deep root systems and fer- 

 tility, 287, 292 ; and deep culti- 



