(595e) Impacts on Soil of Large-Scale Crop Residue Harvest for Biofuel Production

Great enthusiasm exists among government agencies, private industry, and the general public for use of renewable feedstocks, such as crop residues and biomass crops, for production of ethanol and bio-based products. Proponents suggest that stover removal will provide growers with additional sources of income, expand the rural industrial base, and reduce reliance on increasingly scare petroleum, all from material that is now considered ?waste?. However, crop residues are not wasted if returned to the soil. Dynamics of organic matter decomposition give soil life and sustain its critical productive characteristics. Research has shown that residue removal reduces soil organic matter content, crop yield, and soil quality. In addition, residue removal leaves fields more susceptible to erosive losses of sediment and nutrients, with negative consequences for surface water bodies, including eutrophication and siltation. Failure to properly account for and predict the impact of residue removal on future crop yield, soil organic matter content, and water quality will have serious implications for the long-term sustainability of our food, feed, and fiber production systems. Promising research is underway to develop new farming systems that will permit substantial increases in biomass removal while sustaining soil and water resources, but the challenges are formidable.