<P> Agriculture is a major industry in the United States, which is a net exporter of food . As of the 2007 census of agriculture, there were 2.2 million farms, covering an area of 922 million acres (3,730,000 km), an average of 418 acres (169 hectares) per farm . Although agricultural activity occurs in all states, it is particularly concentrated in the Great Plains, a vast expanse of flat, arable land in the center of the United States and in the region around the Great Lakes known as the Corn Belt . </P> <P> The United States was a leader in seed improvement i.e. hybridization and in expanding uses for crops from the work of George Washington Carver to the development of bioplastics and biofuels . The mechanization of farming and intensive farming have been major themes in U.S. history, including John Deere's steel plow, Cyrus McCormick's mechanical reaper, Eli Whitney's cotton gin to the widespread success of the Fordson tractor and the combine harvesters first made from them . Modern agriculture in the U.S. ranges from the common hobby farms, small - scale producers to large commercial farming covering thousands of acres of cropland or rangeland . </P>

Where are most crops grown in the us
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