Sweet sorghum is primarily grown in the U.S. as a source of sugar for syrup and molasses. But the hearty grass has more attributes that could make it especially appropriate for production as a bioenergy crop, U.S. Department of Agriculture (USDA) studies suggest.

Sorghum is a good candidate because of its drought tolerance, adaptability to diverse growing conditions, low nitrogen fertilizer requirements and high biomass (plant material) content, according to molecular biologist Scott Sattler and collaborator Jeff Pedersen with the USDA Agricultural Research Service (ARS) Grain, Forage and Bioenergy Research Unit in Lincoln, Neb. It also produces soluble sugar that can be converted to biofuel. In addition, residual fibers left over from the juice extraction process can be burned to generate electricity.

Sattler and Pedersen's sorghum studies are part of a larger effort by ARS-USDA's principal intramural scientific research agency to answer a government mandate calling for the production of up to 36 billion gallons of biofuel by 2022. Approximately 15 billion gallons of that total will come from grain ethanol, with the remaining 21 billion gallons coming from other feedstocks, including sorghum, sugarcane, grasses such as switchgrass and oilseed crops such as rapeseed and soybean.

USDA reports indicate that sorghum and sugarcane are top candidates for production in the Southeast because they are complementary crops that can extend the biofuel production season and use the same equipment.