Temperate zone sweet sorghumethanol production potential

Abstract The objective of this study was to determine factors that could effect maximum sugar yield of sweet sorghum (Sorgum bicolor (L.) Moench) at temperature zone locations. Four sweet sorghum cultivars were tested for fermentable sugar production potential under irrigated and non-irrigated conditions with 0, 84, and 186 kg ha−1 of added nitrogen fertilizer at two temperature zone locations (40·8° and 42°N latitude). Test sites represented a typical temperate zone irrigated location and a typical corn belt natural rainfall area. Average ethanol (EtOH) yields for the 2-year study were above 3100 liters ha−1 and ranged up to 5235 liters ha−1. The irrigated location produced more gross green weight (89·9 Mg ha−1) compared with the natural rainfall location (65·0 Mg ha−1), but total sugar yield and theoretical EtOH were not significantly different. The results emphasize the potential of sweet sorghum as an alternative energy crop, capable of insulating ethanol prices from shifts in corn prices. Added nitrogen fertilizer had little discernible effect on increasing fermentable sugar production.