Vertical Distribution of Corn Stover Dry Mass Grown at Several U.S. Locations

Corn (Zea mays L.) stover was identified as a renewable non-food agricultural feedstock for production of liquid fuels, biopower, and other bioproducts, but it is also needed for erosion control, carbon sequestration, and nutrient cycling. To help balance these multiple demands, our objectives were to (1) determine height distribution of corn stover biomass, (2) quantify the percentage of stover that is corn cob, and (3) develop a general relationship between plant harvest height and stover remaining in the field for a broad range of growing conditions, soil types, and hybrids in different regions. Plant height, dry grain, stover, and cob yield data were collected at eight US locations. Overall, stover yield increased about 0.85 Mg ha-1 and cob yield increased about 0.10 Mg ha-1 for each 1.0 Mg ha-1 increase in dry grain yield. At grain harvest, the stover-to-grain ratio ranged from 0.64 to 0.96 and cob-to-grain ratio ranged from 0.11 to 0.19. A strong nearly 1:1 linear (r2 = 0.93) relationship between the relative cutting height and relative biomass remaining in the field was observed across all sites. These data were requested by the US Department of Agriculture-Natural Resource Conservation Service to help improve version 2 of the Revised Universal Soil Loss Equation (RUSLE2) and Wind Erosion Prediction System and better estimate corn stover harvest rates based on cutting height or selective organ harvest (e.g., grain and cob only). This information will improve the capacity of RUSLE2 and similar models to predict the erosion risk associated with harvesting corn residues.