Impact of NPK Treatments on Sweet Sorghum (Sorghum bicolor (L)) Yields for Biofuel Feedstock in Piedmont Region of North Carolina

Abstract

Alternative sources for biofuel production such as juice extracted from sweet sorghum are in high demand and proper nutrient management practices need to be established for growing sweet sorghum in order to maximize profits. Sweet sorghum (Sorghum bicolor (L.) Moench) is a promising alternative energy crop. A field experiment was conducted on a North Carolina Piedmont soil to evaluate the production of sweet sorghum as a feedstock for bio-ethanol. Two varieties of sweet sorghum (Dale and M81-E) and four fertilizer treatments (T1: 0, T2: 168-56-168, T3: 84-28-84-soysoap, T4: 168-56-168-Soysoap, of N-P2O5-K2O kg ha-1). The experiment was conducted at the North Carolina A&T research farm in 2011. Dale and M-81-E varieties of sweet sorghum produced significantly higher yields of tops fresh weight and stalk fresh weight from all fertilizer treatments (T2, T3 & T4) than the control (T1). Quantity of juice extracted from stalks was significantly higher for all fertilized treatments compared with the control, but was not affected by variety. No significant difference was observed in total sugar levels in all fertilized treatments. Across all measured variables, T3 gave significantly higher yields than the control but not from T2 or T4. T3 treatment involves half the amount of fertilizer than T2 & T4 and a surfactant effectively cutting fertilizer input expenses by 50%.