Corn Belt states have seen a sizable jump in the amount of land dedicated to corn. This boom has been fueled in part by a federal law requiring oil companies to add corn-based ethanol to the gasoline supply.
Here's a look at the change, in acreage planted to corn, in major corn states since 2006, the year before the ethanol mandate took effect.
Source: United States Department of Agriculture
Note: Due to differences in government survey and sampling methodology, state totals do not necessarily match up precisely with government county-level data also distributed by The Associated Press. For a detailed explanation of the differing survey methodologies, see http://1.usa.gov/1b5FKTq and http://1.usa.gov/19CXFAo