There are costs and benefits for every land management decision. In the Midwest, researchers wanted to better understand the costs of planting perennial biofuel crops like switchgrass or native grasses.

Their work suggests in one category, at least, biofuel crops and corn are equal. Both have a similar water-usage footprint.

When biofuels are burned, less carbon dioxide is released into the atmosphere than is released by fossil fuels. But are biofuels a net positive? To know for sure, researchers need to more accurately calculate the energy required to grow biofuel crops and how their production affects the environment.

Recently, researchers at Michigan State University looked at how switchgrass and other biofuel plants affect the water cycle in the upper Midwest. To measure their affects, scientists installed water sensors in the soil of a number for farm fields in Michigan.

The sensors helped scientists calculate how much water made its way to the water table and how much evaporated back into the atmosphere.

"When we established the different cropping systems in 2008, we installed soil-water sensors at various depths through the root zone," Stephen Hamilton, a scientist at the Great Lakes Bioenergy Research Center, said in a press release. "We've been continuously monitoring the soil water content ever since."

Hamilton and his colleagues found that biofuel crops like switchgrass, miscanthus, native grasses, restored prairies and hybrid poplar trees use roughly the same amount of water as corn crops.

"The message here," Hamilton said, "is that in many settings, perennials may not use more water. For well-drained soils in the upper Midwest at least, and probably for eastern North America in general, these results most likely apply, and water balance would not be adversely affected."

The new research was published this week in the journal Environmental Research Letters.