ed the natural relationship between plants to make their crops more productive. They planted corn, beans, and squash together in small groups, so that the corn plants supported the beans, the nitrogen released by the roots of the bean plants fertilized the corn, and the sprawling squash vines reduced the number of weeds. Corn, beans , squash, potatoes, tomatoes, peanuts, chocolate, and many other plants were originally domesticates by Native Americans.Until the 19th century, agriculture in the United States shared the history of European and colonial areas and was dependent on European sources for seed, stocks, livestock, and machinery. That dependency made American farmers somewhat more ingenious. They were aided by the establishments of societies that lobbied for governmental agencies of agriculture; the voluntary cooperation of farmers through associations; and the increasing use of diverse types of power machinery on the farm. Government policies traditionally encouraged the growth of land settlements. The Homestead Act of 1862 and the resettlement plans of the 1930s were the key agricultural legislative acts of the 19th and 20th centuries. In the 20th century steam, gasoline, diesel, and electrical power came into wide use. Chemical fertilizers were manufactured in greatly increased quantities, and soil analysis was widely employed to determine the components needed by a particular soil to maintain or restore its fertility. The loss of soil by erosion was broadly combated by the use of cover crops; contour plowing in which the furrows follow the contour of the land and are level; and strip cropping.Selective breeding produced strains of both farm animals and crop plants. Hybrids, offspring of unrelated varieties or species, of desirable characteristics were developed; especially important for food production was the hybridization of corn in the 1930s. New uses for farm products, byproducts, and agricultural wastes were a...
