GRASS-CROP AREAS 83 
With proper care in preparation of the soil and in seeding, 
this leguminous crop can be grown without irrigation over 
a very considerable portion of the area. 
114. The arid region.—This includes all the region 
west of the Great Plains where the rainfall is insufficient 
for the growth of crops without the aid of irrigation. 
Besides the two main mountain systems, the Rocky 
Mountains and the Sierra Nevada, there are numerous 
smaller ranges throughout the region between. The term 
Great Basin strictly applies to that portion such as most 
of Utah and Nevada which has no drainage to the sea, 
This name is often applied in a loose way to the whole 
region between the two mountain systems mentioned. 
The general level of this interior region is at 4,000 to 5,000 
feet altitude. Usually at higher altitudes in the mountains 
the climate is increasingly moist. Above about 8,000 
feet the climate is usually humid and the slopes are in 
general more or less forested. 
The climate of the plains and valleys is arid. Crops 
are raised only as water for irrigation can be obtained from 
the streams. Much of the area is sufficiently arid to be 
called a desert. This is especially so in the southern part 
where the summers are longer. Under favorable conditions 
crops can be raised by applying the methods of dry-land 
farming. Such may be the case at the base of a mountain 
slope where there is sub-irrigation through seepage from 
the mountain. The great proportion of this arid region 
is used for stock-grazing in so far as it can be used at all 
for agricultural purposes. Most of the grazing is in the 
mountains but there is some forage on the desert which is 
utilized if water for stock is available (Par. 20). Where 
there is snow in winter, sheep can be pastured, the animals 
depending on the snow for their water-supply. 
