Evaluation of three cultivars of sweet sorghum as feedstocks for ethanol production in the Southeast United States

Sweet sorghum has become a promising alternative feedstock for biofuel production because it can be grown under reduced inputs, responds to stress more efficiently than traditional crops, and has large biomass production potential. A three-year field study was conducted to evaluate three cultivars of sweet sorghum as bioenergy crops in the Southeast United States (Fort Valley, Georgia): Dale, M81 E and Theis. Parameters evaluated were: plant density, stalk height, and diameter, number of nodes, biomass yield, juice yield, °Bx, sugar production, and theoretical ethanol yields. Yields were measured at 85, 99, and 113 days after planting. Plant fresh weight was the highest for Theis (1096 g) and the lowest for Dale (896 g). M81 E reported the highest stalk dry weight (27 Mg ha-1) and Theis reported the lowest (21 Mg ha-1). Theis ranked the highest °Bx (14.9), whereas M81 E was the lowest (13.2). Juice yield was the greatest for M81 E (10915 L ha-1) and the lowest for Dale (6724 L ha-1). Theoretical conservative sugar yield was the greatest for Theis (13 Mg ha-1) and the lowest for Dale (9 Mg ha-1). Theoretical ethanol yield was the greatest for Theis (7619 L ha-1) and the lowest for Dale (5077 L ha-1).