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<br />002-572
<br />
<br />quality, and location with reference to water and
<br />markets. About 75 percent of cropped land is
<br />irrigated.
<br />The principal crops grown under irrigation are
<br />vegetables, cotton, citrus and other fruits, feed grains,
<br />and alfalfa. Dryland crops are mainly small grains,
<br />pasture grass, and dry beans.
<br />Rangeland. - Rangeland includes much of the
<br />desert, essentially all intermediate hill land, and some
<br />steep mountainous land. Northern and southern
<br />desert shrubs, salt desert shrubs, grasses, and forbs
<br />provide forage for cattle and sheep to support a
<br />substantial livestock industry. Almost all the acreage
<br />also is being used for other purposes. Other uses
<br />usually include extensive wildlife and recreation use,
<br />as well as the more intensive use such as mineral
<br />exploration and development. Although rangelands
<br />produce a relatively small amount of runoff, the
<br />damage in soil erosion and siltation is disproportion-
<br />ately great because of the condition of the lands.
<br />Forest Land. - Forest land is located mainly in
<br />the mountain terrain and adjacent foothills. An
<br />exception is the coastal redwood area where forests
<br />also occupy valley . floors. The principal forest growth
<br />is coniferous, consisting of a great variety of pines,
<br />flrs, and spruce. Aspen, oak, and maple are hardwood
<br />species and make up nearly one.third of the vegeta-
<br />tion. Chaparral and mountain brush are forest shrubs
<br />which cover more than 20 percent of the forest land.
<br />Some 80 percent of the precipitation in the Pacific
<br />Southwest falls as snow on high elevation watersheds
<br />which are largely forested and melts in late spring.
<br />
<br />
<br />land Resources
<br />
<br />Modern man's fascination with the Pacific South-
<br />west's land began with the Spanish explorers of the
<br />16th century. However, for a very long time -
<br />perhaps 30,000 years - man has been using the land
<br />and its resources. Indian farmers of prehistory de-
<br />veloped irrigation systems along the Salt and Gila
<br />Rivers in Arizona 1,500 years before Coronado set
<br />out to fmd the Seven Cities of Cibola.
<br />Spanish settlement of the region during the 1700's
<br />introduced agricultural development through irriga-
<br />tion and the raising of domestic livestock. The Spanish
<br />and Mexican land grants established private owner-
<br />ship in most of the region's prime grazing and
<br />cropland.
<br />The United States gained control of the region in
<br />the mid-1800's. Private titles to valid grants made by
<br />the Spanish and Mexican Governments were eventu-
<br />ally accepted. Discovery of minerals, grants to railroad
<br />corporations, States, and private individuals for the
<br />purpose of encouraging settlement increased the
<br />acreage of privately owned land. Much of the land
<br />base suitable for intensive agriculture, urban develop-
<br />ment, and industrial use is now in private ownership.
<br />However, extensive areas of public land are suitable
<br />for these purposes if water is made available. (See
<br />table 5.)
<br />
<br />land Resource Groups
<br />
<br />Cropland. - Land used for crops is generally the
<br />flattest and the best land from the standpoints of soil
<br />
<br />Table 5.-Land resource groups, 1965 (1,000 acres)
<br />
<br /> Lower Upper
<br /> California Great Basin Colorado Colorado Pacific Southwest
<br />Cropland 10,741 3,208 1,-816 2,572 18,337
<br />Rangeland 40,168 59,572 57,586 38,107 195,433
<br />Forest land 46,539 17,022 29,997 27,381 120,939
<br />Urban 2,347 776 513 368 4,004
<br />Other 4,387 5,139 76 3,806 13,408
<br />Total 104,182 85,717 89,988 72,234 352,121
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