MINNEAPOLIS (AP) — Minnesota converted more wetlands into farmland than any other state when crop prices spiked between 2008 and 2012.

That's according to a new study by University of Wisconsin-Madison researchers.

About 250,000 acres, or nearly 400 square miles, were converted to row crops. Most was grassland, but 25,000 acres were wetlands — more than any other state.

Also, 13,000 acres of forests were converted — the second largest forest conversion in the country.

The study estimated that 7.3 million acres were converted nationwide. According to the study, the increased carbon emissions from the additional corn and soybean crops alone would be equal to a year's emissions from 34 coal-fired power plants.

The study was published Thursday in the journal Environmental Research Letters.