| OCR Text |
Show land, and sufficient water for a material expansion of irrigation; the difficulty is to bring the two to- gether at a cost low enough to make production feasible. Most of the inexpensive sites have been used, and the dispersal of irrigable lands, difficult terrain, and limited variety of crops will make it necessary to plan future expansion carefully. Another major problem is that of increasing the stability of agriculture in this region of extreme rainfall variability. Land abandonment and agri- cultural distress have recurred with each drought period. The use of water to promote greater stability of agriculture would mark a major advance. Mineral resources are found throughout this area. Oil is important in the economy of the area around Casper and Cody, Wyo., and Shelby, Mont. Other fields in Montana and Wyoming are being explored, and some are believed to have important possibil- ities. Natural gas in several localities is used for domestic and other purposes. Many localities are underlain with soft coal or lignite, and several com- munities grew up based on the coal mining opera- tions, which supply local needs but due to the dis- tance to large markets have never been of more than local importance. The growing use of Diesel fuel rather than coal by railroads is seriously affect- ing the coal mining economy. These large deposits of soft coal and lignite may be looked to as one source of synthetic fuels to meet future national needs. The Black Hills are an eastern extension of this region. A circular area of low mountains in southwestern South Dakota, they rise to over 7,000 feet above sea level. The thin, rocky soils are densely forested. The open parks and glades are heavily used as summer range by cattle and big game. Most of the area is in a national forest. Precipitation is considerably heavier than in the surrounding plains. Around the base of the hills are numerous small irrigation enterprises dependent on the flow from the mountain snow-melt water, including the Belle Fourche Project. The lime- stone soils surrounding the mountains are very subject to erosion. Recreation use of the Black Hills is extensive. Not only are they a mecca for the Missouri Basin residents, but the adjacent national monuments and State parks draw visitors from throughout the Nation to see these geological wonders and scenic attractions. A number of mining operations are carried on, one of which, the Homestake Gold Mine, is very large. The Plains Region The central area of the Great Plains is a region of great instability, for which climatic conditions are largely responsible. The average precipitation is only about 16 inches and the average of the 10 wettest years out of 40 is only 20 inches. Even the wettest summers have only 12 inches, while the 10 driest summers averaged only 4 inches. Sunshine is 80 percent of that possible, and the average humidity is low. Constant winds cause high evap- oration. Although dry farming is extensively practiced, agriculture under such conditions is often precar- ious. Wheat is the principal grain although oats and kaffir corn are also grown extensively. In good years there are abundant crops, but early drought or lack of winter snow cover may result in widespread dust storms and crop failure. Long droughts and severe financial reverses have caused major migrations from the region, and the shorter, gradual losses of population. After each great drought, recovery has been slow and uncertain. Much of the rolling area of the plains is grass- land. Originally it provided excellent livestock range, but it has been depleted by droughts and overgrazing. Many of the nutritious grasses have now been replaced by less valuable vegetation. Large areas have been plowed for wheat, which has resulted in loss of the valuable topsoil, especially in the southern part of the basin. Large parts of the area are rough. Some of these are badlands. Once part of the plain, the deep clay soils of these areas became exposed through depletion of the cover by drought or over- grazing. After exposure these soils are rapidly desiccated. A great gully system originates which grows both laterally and downward. When thor- oughly wet, the clays almost melt. The fine ma- terials are easily floated away. These sterile fines characteristically keep the waters of the Missouri and many of its tributaries muddy at all times. Bad- lands occur in each of the plains States except Kansas. The farms are large and the population evenly but sparsely distributed over the region. Towns are small and widely scattered. There is some controversy as to irrigation in sections of the plains region. During wet years, rainfall is adequate to produce crops without irri- gation. Also, the percentage of dry years is less than farther west. Irrigation is practiced along the Platte, and to a much less extent along other 167 |
