Researchers at the University of Minnesota are looking for ways to take the burden off corn as a source of fuel in ethanol, the Star Tribune reported, as the world demand for both food and fuel projected to double in the next 50 years.
 
“Unless we produce food and biofuel in an efficient manner, they will be directly competing with each other,” said University of Minnesota ecology professor David Tilman. “We will have high prices for both.” 
 
Researchers are examining a solution that would see ethanol plants supplied with a diverse mixture of prairie grasses instead of corn. The grasses produce more net energy per acre than corn, and researchers say the grasses also act as a sponge for greenhouse gases before they’re harvested by soaking them out of the air and into their roots and surrounding soil.
 
A director of the Minnesota Corn Growers Association has warned that supplanting corn with grasses would be a complex, costly task that could take years, but Tilman said that prairie grasses could mean a new, cheap-to-produce cash crop that would be more opportunity than threat to farmers.
 
Researchers reported that a field planted with a variety of prairie grasses and flowering plants packed more than three times the energy of single-variety grasses. The study estimated that mixed prairie grasses grown on marginal farmland would yield 51% more energy per acre than corn cultivated on fertile land.  The study also found that the prairie grasses absorb about 14 times more greenhouse gases than is released in producing grass-based fuel.
 
The Minnesota researchers found that a single species of grass is less promising than a blend a prairie grasses, of which they studied 16 varieties. 
 
“Switchgrass is very productive when it’s grown like corn, in fertile soil with lots of fertilizer, pesticide and energy inputs, but this approach doesn’t yield as much energy gain as mixed species in poor soil, nor does it have the same environmental effects,“ Jason Hill, a researcher who worked with Tilman, said in a statement.