Washington, November 24 A new study has determined that 50 million US acres of cropland, idle cropland, and cropland pasture could be converted from current uses to the production of perennial grasses, such as switchgrass, from which biomass could be harvested for use as a biofuel feedstock quite efficiently.

Economically viable production of a perennial grass monoculture from which substantial quantities of biomass are removed annually is expected to require nitrogen fertilizer.

An agronomist at Oklahoma State University, Regents Professor Emeritus Charles Taliaferro, designed and conducted an experiment to determine biomass yield from alternative levels of nitrogen fertilizer for a single and double harvest per year system for four perennial grass species.

Agricultural economics graduate student, Mohua Haque, used the data produced in the field experiments to determine the most economical species, level of nitrogen, and harvest frequency for several sets of nitrogen fertilizer prices and hypothetical biomass prices.

According to Haque, "For the soil and weather conditions that prevailed at the experiment site for the duration of the study, switchgrass clearly produced more dry biomass per dollar cost than the other three species."

"If perennial grass for biofuel feedstock is the best alternative for a field, and if the biomass price exceeds the cost of production, the optimal strategy would be to establish switchgrass, and in post-establishment years, to fertilize with 60 pounds of nitrogen per acre per year, and to harvest once per year after senescence," Haque said.

If an economically viable system for conversion of biomass from perennial grasses to biofuels is developed, millions of acres may be bid from current uses and seeded to switchgrass.

Results from the study will be incorporated into a model at Oklahoma State University to evaluate the economic potential of alternative cellulosic biofuels production systems for Oklahoma. (ANI)