GROWN ON THE RANGE: Across the Dakotas and Nebraska, more than 1 million acres of the Great Plains are giving way to cornfields as farmers transform the wild expanse that once served as the backdrop for American pioneers.
MELTING POT: This Corn Belt transformation is being fueled in part by America's green energy policy, which requires energy companies to blend billions of gallons of corn ethanol into their gasoline. In 2010, fuel became the No. 1 use for corn in America, a title it held in 2011 and 2012 and narrowly lost this year.
HOT MARKET: Plowing untouched grassland releases carbon dioxide that has been naturally locked in the soil. It also increases erosion and requires fertilizers and other industrial chemicals. That can destroy native plants and wipe out wildlife habitats. It appears so damaging, scientists warned that America's corn-for-ethanol program would fail as an anti-global warming strategy if too many farmers tilled virgin land.