Water Quality Impacts of Corn Production to Meet Biofuel Demands

The overall goal of this project was to quantify the long-term water quality impacts of land management changes associated with increased demands for corn as a transportation biofuel feedstock in the United States. A modeling approach that considers a nonpoint source model, Groundwater Loading Effects of Agricultural Management Systems and National Agricultural Pesticide Risk Analysis, was used to simulate annual losses in runoff, percolation, erosion, nitrate-nitrogen, total phosphorus, atrazine (1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine), and pyraclostrobin (Methyl {2-[1-(4-chlorophenyl)-1H-pyrazol-3-yloxymethyl] phenyl} methoxycarbamate) to the edge-of-field and bottom-of-root zones associated with multiple cropping scenarios. Model results for representative soils, throughout Indiana, were analyzed to determine 10% (worst case) and 50% (average case) probability of exceedence in the aforementioned water quality indicators. Modeling results indicated significant differences (p<0.05) in water quality indicators between continuous corn and corn-soybean rotations. The results showed that agricultural management decisions would have greater impacts on nutrient, runoff, erosion, and pesticides losses from agricultural fields compared to water quality indicators associated with the projected changes in crop rotation systems. The model results point to the need for additional research to fully understand the water impacts of land management decisions associated with corn grain as a feedstock for biofuel production.