32 DRY-FARMING 
farm it would be an impossibility. It must not be 
forgotten, however, that some of the best dry-farm 
lands of the West are found in the small mountain 
valleys, which usually are pockets of most fertile 
soil, under a good supply of rainfall. The foothills 
of the mountains are almost invariably excellent 
dry-farm lands. Newell estimates that 195,000,000 
acres of land in the arid to sub-humid sections are 
covered with a more or less dense growth of timber. 
This timbered area roughly represents the mountain- 
ous and therefore the nonarable portions of land. 
The same authority estimates that the desert-like 
lands cover an area of 70,000,000 acres. Making 
the most liberal estimates for mountainous and 
desert-like lands, at least one half of the whole 
area, or about 600,000,000 acres, is arable land, 
which by ‘proper methods may be reclaimed for 
agricultural purposes. Irrigation when fully de- 
veloped may reclaim not to exceed 5 per cent of 
this area. From any point of view, therefore, the 
possibilities involved in dry-farming in the United 
States are immense. 
Dry-farm area of the world 
Dry-farming is a world problem. Aridity is a 
condition met and to be overcome upon every con- 
tinent. McColl estimates that in Australia, which is 
somewhat larger than the continental United States 
