432 
162; early in spring, 159, 160; 
during season, 160; depth of, 
157; must destroy weeds, 162; 
of growing crops, 163; of rows 
of lucern, 248; of fall-sown crop 
in spring, 159; between rows 
of plants, 163; implements for 
soil cultivation, 310. 
Cultivators, 314. 
Currants, on dry-farms, 253. 
Dakotas, soils of, 74; type of rain- 
fall over, 40; wheats for, 236; 
milo in, 246. ° 
Davidson and Chase, 307. 
Defiance wheat, 240. 
Desert, essentially fertile, 58, 72, 73. 
Disk harrow, 311, 313. 
Disking, 414; after harvester, 127; 
after fall plowing, 129; fall- 
plowed land in spring, 129, 159; 
to reduce run-off, 98; crop in fall, 
226; crop in spring, 227. 
Dog Valley, state well in, 341. 
Drainage, plant food in drainage 
water, 65; in arid countries, 66. 
Drill, invented by Tull, 226, 317; 
types for sowing, 318. 
Drill culture, 225; and snow con- 
servations, 225. : 
Drouth, defined, 49, 400, 402, 412; 
how to farm against, 416; year 
of drouth, 399; year of drouth 
disproved, 403-412; fallow in- 
dispensable in year of, 203; of 
1910, 411. 
Dry-farming, defined, 1; a mis- 
nomer, 2; a technical term, 4; 
vs. humid-farming, 4; fun- 
damental problems, 6,9; theo- 
retical basis of, 11; climatic 
features of areas, 35; physical 
features of territory in United |. 
States, 35; areas in United 
States, 25-32; areas in world, 
32-34:. soils, 50-80; three main 
conditions, 192; water the crit- 
INDEX 
ical element in, 203; and ma- 
chinery, 302, 327; crops for, 232; 
certainty of crop yield, 204; 
importance of steady productive 
power, 293; and irrigation go hand 
in hand, 350; total area in 
United States, 27; originated 
in several places, 193; system 
same in divers localities, 194; 
in a nutshell, 413. 
Dry-farm, size of a dry-farm, 301. 
Dry-farmer, temperamental char- 
acteristics, 330; acreage for one 
man, 301. 
Dry-farming Congress, organization 
and history, 874; opinions on 
cultural methods, 194. 
“ Dry-land agriculture,” 4. 
Dry matter, and transpiration, 182- 
186; methods for determining 
water for, 12; water for one 
pound of, 12; water cost in 
arid countries, 17. 
Durra, 245. 
Durum wheat, 237. 
Ebermayer, 150, 155. 
Egypt, sands of Egypt fertile, 58. 
Electricity, electric motors, 322, 325; 
for pumping, 342. 
Elm, on dry-farms, 2538. 
Emmer, 243. 
Engines, in dry-farming, 321. 
England, Boswell oats from, 241; 
steam plowing in, 323. 
Escobar, 244. 
Eser, 148. 
Europe, steam plowing in, 323. 
Evaporation, formation of water 
vapor, 132; factors increasing, 
133, 136; effect of temperature 
on water vapor, 133; from free 
water surface, 132; and relative 
humidity, 46; measure of arid- 
ity, 131; under humid and arid 
conditions, 149; possible evap- 
oration in arid districts, 131; 
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