Potential of Growing Sorghum As Bioenergy Feedstock on Lands Economically Unfit for Maize Production.

Most of the focus of growing biomass feedstocks on marginal lands to meet the 2022 national biofuel target mandate has been on perennial grasses like giant miscanthus (Miscanthus × giganteus) and switchgrass (Panicum virgatum). However, information on comparative production potential of different sorghum (Sorghum bicolor L.) species versus mainland corn (Zea mays L.) production is limited. The objective of this study was to compare the biomass yield, nutrient-use efficiency, structural and non-structural carbohydrate pools of continuous sorghum systems with continuous corn under varying nitrogen (N) fertilizer rates across multiple site-years. A replicated field plot study was conducted from 2011 to 2015 with five N rates (0 to 200 Kg N ha^-1) as main plots and crop species (dual purpose sorghum, sweet sorghum, photo period sensitive sorghum, and corn) as sub-plots. Treatments were established in the first year and stayed in the same plots until the end of study. Preliminary analysis suggests that the mean above-ground biomass yield of corn was found lowest among species ranging from 1.4 to 10.1 Mg ha^-1 across sites and N rates and highest for photo-period sensitive sorghum ranging from 4.3 to 14.4 Mg ha^-1. The biomass yield of dual-purpose sorghum and sweet sorghum yields were in-between corn and photo-period sensitive sorghum yields except at SEPAC site where sweet sorghum outperformed photo-period sensitive sorghum. ANOVA and regression analyses will be conducted to achieve stated objectives and results will be presented at the meetings.