Corn Stover Biofuel Potential and Nutrient Removal Across the Southeastern US.

Corn (Zea mays L.) biomass yield and composition vary with variety, plant portion and management practices. It is essential to understand the theoretical ethanol potential of the total and partial corn biomass to determine which parts of the plant should be harvested as biofuel feedstock. Two continuous corn field studies were established in Alabama and one in South Carolina. Stover removal management practices (0 and 100% removal) were performed at all three locations.  In Alabama the use of rye (Secale cereale L.) as a winter cover crop was also incorporated as a management practice. The soil types in Alabama were Compass and Decatur; in South Carolina the soil was a Coxville/Rains-Goldsboro-Lynchburg association. These three sites were investigated for differences in carbohydrate content, theoretical ethanol yield (TEY), energy content in the form of high heating value (HHV), and nutrient composition among five plant fractions: whole plant (stover); above the first ear excluding cobs (top); below the first ear (bottom); cobs; and above the first ear including cobs (above-ear). The distribution of carbohydrates, nutrients, TEY, and HHV varied significantly among the corn stover portions in every location. The use of a rye cover crop and stover harvest had small impact on biofuel potential. Removing the above-ear portion of the stover only would result in lower removal of nutrients by 46-68% when compared to harvesting the whole plant biomass. Data from this study suggests that the above-ear portions of the stover are the most desirable for bioethanol production at every location.