Lecture – 8 geography of the usa

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Agriculturally, the United States is richly productive, with many crops providing a surplus for export. Most of the eastern two-thirds of the conterminous United States is arable the land of the western United States is used mostly for grazing but has considerable irrigated lands for crops. The principal U.S crops are: fruit, truck farming products, and special crops (including rice and sugarcane) along the Gulf coast, in irrigated areas of the west, and near urban areas in the east; cotton in the southeastern states and on some irrigated lands in the west; tobacco, peanuts, fruit and general farm products on the Atlantic coastal plain and in the eastern Appalachian; dairy products and hay in the northern states; and corn, wheat, and soybeans on the plains.
Livestock on farms habitually totals over 100 million cattle additional millions of hogs and sheep and hundreds of millions of chickens and turkeys. The grazing capacity of the land is very unequal. The humid half of the country can support as many as cows per year per sq mi (193 per sq km, whereas the semiarid and arid western half can support fewer than 100 per sq mi (40 per sq km) and some parts support only about 10 head sq mi (4 per sq km).
Commercial forests cover more than 2,000,000 sq km, especially in the northwestern, northern Midwestern, and the southeastern states. They produce, besides lumber, paper pulp, resins, and syrup. The annual forest cut and burn is less than growth, but care is needed to minimized water and erosion losses due to grazing and lumbering. In recent years increased recycling of paper is reducing consumption of paper pulp.
Changing interests in water resources are reflected in the history of water management. First, the need for transportation led to the building of canals, such as the ERIE CANAL, in the eastern states in the early 19^th century. Second came the great period of flood control, especially along the Mississippi River. Third came a period of large-scale development of irrigation system in the west, beginning around the turn of the century. Fourth came a period of developing hydroelectricity, beginning during the 1930s. Today’s principal concern is pollution control. In the future will come a stage when controls will be needed to prevent groundwater withdrawals from exceeding recharge.
Mineral production, although less than 5 percent of the GROSS NATIONAL PRODUCT (GNP), is vitally important. No nation is self-sufficient in minerals, and although the United States has more than its share, nevertheless domestic production of many minerals is less than demand, necessitating imports. Fossil-fuel shortages combined with high demand threaten the Unites States with severe economic problems. Alternate sources of energy such as solar, geothermal, and wind energy are in the early stages of development.