INDEX 



431 



Clay, from combined silica ; in 

 soils, 56 ; and climate, 57 ; and 

 hardpan, 64 ; and native vege- 

 tation, 80 ; soils defined, 57 ; in 

 soil classification, 57 ; depth of 

 planting in, 221 ; soils respond 

 to cultivation, 157. . 



Clearing, machiuery for clearing 

 land, 302. 



Climate, climate features of dry-farm 

 area, 35 ; summary of climate in 

 dry-farm territory, 48 ; does not 

 change, 400 ; and proportion of 

 plant parts, 261. 



Clover, pounds water for one pound, 

 15 ; taproot of, 83 ; for nitrogen, 

 297. 



Coal, for steam pumps, 342. 



Colorado, area, 26 ; type of rainfall 

 over, 40 ; soils of, 74, 76 ; nitrogen 

 in Colorado soils, 286 ; deep and 

 fall plo'wing in, 195 ; fallowing 

 in, 197 ; field peas in, 249 ; n:iilo 

 in, 246 : dry-farm orchard in, 

 252 ; pumping plants in, 342 ; 

 first Dry-Farming Congress held 

 in Denver, 374 ; present status 

 of dry-farming in, 389. 



Colorado Basin, soil district, 76 ; 

 status of dry-farming in, 388. 



Colorado, Canon of, description, 35. 



Colorado Station, first experiments 

 on dry-farming, 366. 



Columbia Basin, description, 36 ; 

 soil districts, 74 ; use of roller in, 

 315; weeder used in, 314; be- 

 ginnings of dry-farming in, 357 ; 

 an originator of dry-farming, 

 193 ; present status of dry-farm- 

 ing in, 384. 



Commercial fertilizers, and dry- 

 farming, 296. 



Composition, chemical composition 

 of arid and humid soils, 68 ; of 

 crops, 257—277 ; young plants 

 rich in protein, 274 ; commer- 

 cial value of superior quality of 



dry-farm crops, 278 ; variations 

 due to climate, 271-274; varies 

 with water supply, 267-271 ; a 

 reason for variation in, 274-275 ; 

 causes of variations in, 267. 



Continuous cropping, dangerous, 

 203. 



Cooke, 369. 



Corn, 243 ; pounds water for one 

 pound, 15, 16 ; depth of root 

 penetration, 86, 87 ; root sys- 

 tem, 83 ; water absorbed by 

 seeds of, 209 ; repeated drjdng 

 in germination, 218 ; amount to 

 sow, 224 ; mechanical planters, 

 320 ; harvesters for, 321 ; varia- 

 tion in composition, 267 ; im- 

 portance of humus for, 297 ; 

 water and yield, 346. 



Cracked land, danger of, 141. 



Crimean wheat, 238. 



Crop, see also Plant; for dry-farm- 

 ing, 232 ; for irrigation and dry- 

 farming, 256 ; varieties, 234 

 condition of good dry-farm, 234 

 adaptation of, 232 ; care of, 226 

 harrowing of, 162 ; not on fallow 

 land, 124 ; composition of dry- 

 farm, 257 ; nutritive substances 

 in, 264 ; from dry-farms highly 

 nutritious, 275 ; water in dry- 

 farm, 262 ; yield varies with 

 water applied, 345 ; producing 

 power of rainfall, IS ; soil- 

 water necessary to mature, 118; 

 effect on transpiration, 178 ; to 

 prevent soil blowing, 198 ; special- 

 izing in dry-farm, 279 ; problems, 

 256. 



Cultivation, see also Tillage; saves 

 moisture, 152-156 ; experiments 

 showing value of cultivation in 

 reducing evaporation, 154-155 ; 

 increases depth of soil-water, 116 ; 

 effect on transpiration, 187 ; and 

 humus, 198 ; and root systems, 

 92 ; time of, 158 ; after rains, 



