INDEX 



425 



Control of moisture, chapter on, 222 

 Cordilleran center of accumulation, 



45 



Corn, acreage, 1909, 412 

 belt rotations, 382 

 comparison, cultivated, scraped, 



weeds allowed to grow, 351 

 cultivation, 353 



effect on yield of root pruning 

 and deep and shallow cultiva- 

 tion, 355 

 grown on dry land, 252 



on swamp land, effect of po- 

 tassium- on, 404 

 method of preparing seed bed 



for, 348 

 planter, 338 

 production, 1909, 413 

 results of cultivation, 352 

 yields of, different methods <>f 



tillage, 354 



Cotton belt, rotation for, 384 

 Cottrell, II. M., pounds seed per acre 



for different crops, 255 

 Cover and catch crops, 161 

 Cox, II. II., with Cates, J. S., re- 

 sults corn cultivation, 28 states, 

 353 

 Cracks, in black clay loam, 136 



shrinkage, effect of, on percola- 

 tion, 219 

 Cropping, alternate rs. continuous, 



yields, 250 

 continuous vs. after fallow, 



wheat yields, Montana, 248 

 IOBS of organic matter, due to, 



151 



systems of, 248 



Crop requirements, plant food, 390 

 Crops, alkali-resistant, growing of, 



on alkali land, 285 

 catch and cover. 161 

 deep rooting, effect of, 345 



on moisture capacity, 171 

 for dry farming, see dry-farm- 

 ing crops 

 for irrigated land, see irrigated 



land, crops for 



non-tilled, factor in maintain- 

 ing organic matter, 171 

 plant food in, 390 



Crops, protection from erosion by 



catch and cover, 362 

 meadows and pastures, 361 

 rotation of, aid in maintaining 



organic matter, 171 

 ten-year average yield of, by 

 states in United States, 407, 

 408 

 Crystalloids, dialysis and diffusion 



of, 131 



Cultivation after irrigation, 273 

 and summer tillage in dry farm- 

 ing, 246 

 level, 355 

 object of, 350 

 of corn on gray silt loam on 



tight clay, yields, 353 

 of corn, Illinois yields. 352 

 results of deep and shallow, with 

 and without root pruning, 

 corn, 355 

 ridged, 356 

 Cultivators, 337 

 blade, 339 

 disk, 339 

 shovel, 338 

 weeder, 340 

 Cumulose soils, 27 

 Currents of air, convection, source 



of loss of soil heat, 2!Hi 

 Cyanamid, calcium, 400 



Dams, for filling gullies, concrete, 



273 



earth, 271, 272 



Deacon, (J. I 1 '., relation between ve- 

 locity and amount of ma- 

 terial carried by streams, .'!:{ 

 Debris cliff, 30 

 Decomposition, effect of, on loss of 



constituents of rock, 22 

 of organic matter by drainage, 



225 



of rocks, 1 1 

 by acids, 19 

 by animals, 25 

 by plants. 25 

 tli rough solution, 22 

 Deep-rooting crops, etl'eet of, 345 



on water capacity of soil. 



_>::i 



Deherain, effect of aeration on nitri- 

 fying bacteria. '!-<> 

 loss of nitrates by leaching. '\'2'2 

 Denitrification, nitrates lost by, 3'2.'l 



