Vertical Distribution of Corn Biomass as Influenced by Cover Crop and Stover Harvest

Corn (Zea mays L.) production for grain is important given its many uses for human food, animal feed, and other industrial products. Additionally, the abundance and potentially large biomass yield makes corn an attractive bioenergy feedstock. The objective of this study was to evaluate the effect of in-season weather conditions, rye (Secale cereale L.) as a winter cover crop, and corn residue harvest on grain yield and biomass distribution across two soil types. Grain, as well as, total and partial stover yields (below the ear, above the ear excluding cobs, cobs alone, and above the ear including top and cobs) were measured from 2009 to 2011 at two sites with different soil types: loamy sand and silt loam, in central and northern Alabama, respectively. Significant differences in grain and biomass yields were observed among individual years and locations. Grain yields were positively correlated with seasonal cumulative precipitation and negatively with seasonal average temperature at both locations. In central Alabama, the 3-yr use of a rye cover crop increased corn biomass yields compared to rye removal while there was no difference compared to plots without a rye cover crop. The 3-yr corn residue management effect was not significant at any location. Based on this study, harvesting the above-ear corn plant fraction could be an attractive option for partial biomass harvesting in southeastern United States.