Miscanthus. Photo: Tau’Olunga, Wikimedia Commons.

Perennial crops like the tallgrass miscanthus can be turned into ethanol like corn, but give off less nitrogen into the atmosphere, according to a University of Illinois study.

Limiting nitrogen is important because it can produce nitrous oxide, a greenhouse gas that furthers global warming. And nitrate can contaminate drinking sources and leach into lakes where it contributes to lethal dead zones for fish life.

Ethanol is added to gasoline to reduce dependence on the fossil fuels that contribute to global warming. But it’s counterproductive to produce ethanol in a way that makes yet another powerful greenhouse gas – nitrous oxide.

“Corn production with large fertilizer inputs leads to large losses of nitrogen into the environment, both through gas emissions of nitrous oxide and leaching of nitrate,” Mark David, an Illinois biogeochemist reported.

The study compared miscanthus, switchgrass and mixed prairie species of grass with corn and soybean.

Each of the perennial crops were “highly efficient at reducing nitrogen losses, with miscanthus having the greatest yield” of biomass used for fuel, according to the university.