Location: Soil, Water & Air Resources ResearchTitle: Sustainable corn stover harvest strategies for Midwest agricultural landscapes Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2014
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: To support emerging U.S. cellulosic bioenergy industries, 239 site-years of data from field studies at 36 sites in seven states were recently summarized in BioEnergy Research by the ARS Resilient Economic Agricultural Practices (REAP) team [formerly the Renewable Energy Assessment Project (REAP) team] in collaboration with the Department of Energy (DOE) Regional Research Project – Corn Stover Team, and several university partners associated with the NIFA Sun Grant Initiative. This presentation summarizes important results from that mult-location, trans-disciplinary project and illustrates the importance of striving for a landscape vision to ensure Midwestern corn (Zea mays L.) stover harvest for bioenergy and/or bio-products occurs in a sustainable manner and does not result in soil degradation or other unintended environmental consequences. Key findings include: (1) Crop residue management costs can be reduced by harvesting a portion of the residual corn stover, BUT excessive stover harvest can degrade soil health in several ways: (a) Reduced particulate organic matter (POM) levels, (b) Smaller average aggregate size, and (c) Undesirable shifts in the soil microbial community; (2) Compared to harvesting only corn grain, N, P, and K removal are increased by at least 16, 2, and 18 kg Mg-1 of stover removal. Sampling at physiological maturity, about 3 to 4 weeks before grain harvest projects even higher rates of nutrient removal; (3) Averages are meaningless – variability associated with different soils, weather patterns, and crop growth conditions resulted in minimum residue return projections for 35 studies to be 6.38 ± 2.19 Mg stover ha-1 yr-1; and (4) Spatial and temporal variability can be addressed by using tools such as the Landscape Environmental Assessment Framework (LEAF) to develop sub-field management strategies that are sensitive to and capitalize on subtle landscape differences. Finally, based on the lessons learned from this coordinated multi-location research project, the ARS-REAP team is now striving to diversify crop rotations in different ways for various landscapes. This includes incorporating cover crops, double-cropping with oilseeds, and increasing the presence of perennials by developing innovative harvest strategies, multiple uses and greater “market pull” for a traditional Midwestern crop – alfalfa (Medicago sativa L.). Collectively, these soil and crop management strategies will help diversify Midwestern landscapes, improve soil health, and protect soil and air quality, while simultaneously providing sustainable supplies of high-quality feedstock for production of bioenergy and other bio-products.