Corn is the common name for the cereal grass widely grown for food and livestock fodder. Corn ranks with wheat and rice as one of the world's chief grain crops, and it is the largest crop of the United States. The Cultivation of corn in exists in the United States southwestern for least 3000 years. There are many varieties of corns with widely different characteristics; some mature in 2 months; others take 11 months. In the US sweat corn is commonly grown for human consumption as a vegetable.
World output of corn in the early 1990s stood at more than 469 million metric tons annually; in volume of production, corn ranked third behind wheat and rice. A net gain of about 11 percent in production was realized during the 1980s; intensive cultivation with heavy use of fertilizer and herbicides was responsible for the increase. The United States is the leading corn-growing country, with more than 40 percent of the world's production. Most of its crop is grown in the Midwestern region known as the Corn Belt, comprising Ohio, Indiana, Illinois, Iowa, Missouri, Kansas, and Nebraska. The other leading corn-growing nations are China, Brazil, and Mexico.
Approximately 61 percent of the corn sold by farmers in the United States are used as livestock feed. About half of that amount is fed directly to hogs, cattle, and poultry, and the rest is used in mixed feeds. Another 22 percent of U.S. corn is exported; the remaining 17 percent is sold as food and taken by commercial users for the production of alcohol and distilled spirits, syrups, sugar, cornstarch, and dry-process foods.