December 18, 2006

Prairie grass may replace corn in ethanol

With world demand for food and fuel reaching high levels, US researchers fear corn might not be able to fill both stomachs and gas tanks.

Researchers at the University of Minnesota, led by David Tilman, however, have come out with a solution. A diverse mixture of native prairie grasses could yield more net energy than ethanol from corn, they found. Grass-based fuel could even lead to a net decrease in atmospheric carbon dioxide.

A director of the Minnesota Corn Growers Association though felt otherwise. Supplanting corn with grasses would be a complex, costly task that could take years, he warned.

Tilman pointed out prairie grasses could represent a new cheap-to-produce cash crop that would be more of an opportunity than threat to farmers.

In a cover story published in "Science Magazine", the researchers reported that a field planted with a medley of prairie grasses and flowering plants packed more than triple the energy of single-variety grasses.

Their study also estimated that mixed prairie grasses grown on marginal farmland would yield 51 percent more energy per acre than corn cultivated on fertile land.

Also, the diverse mixture of prairie grasses was grown on depleted land without the fertilisers and pesticides commonly used on corn crops. Since the grasses require almost no maintenance, less gasoline and diesel fuel would be burned tending to fields. And because prairie grasses act like traps for greenhouse gases, greenhouse gas reductions would be 6 to 16 times higher than from corn-based ethanol, the researchers estimated.

Incidentally, US President George W Bush has touted research into making ethanol from switchgrass. But according to researchers, a single species of grass was far less promising than a blend of prairie grasses for ethanol production.

The ethanol industry and corn growers on the other hand are still apprehensive whether prairie grasses could supplant corn as a major ingredient in producing ethanol as they believe corn would always remain a king in ethanol production.