Measuring The Merits Of Corn Stover-Based Ethanol

Science Daily — Stover refers to stalks, leaves and cobs that remain in corn fields after the grain harvest. Farmers leave it there to revitalize the soil and prevent erosion. Now, thanks to scientific and technological advances, farmers face the prospect of harvesting stover for cellulosic sugars that can be fermented into ethanol.

However, this presents a quandary, notes Wally Wilhelm, a plant physiologist in the Agricultural Research Service's (ARS) Agroecosystem Management Research Unit at Lincoln, Neb.

On the one hand, harvesting stover for sugars to make ethanol may lessen dependence on crude-oil imports. On the other hand, leaving stover in place may help prevent soil erosion caused by strong winds or intense rainfall. It also replaces lost nutrients and sequesters carbon in the soil, lessening CO2 accumulation in the atmosphere as a greenhouse gas and its contribution to global climate change.

This summer marks the second season of field studies under a five-year project that Wilhelm is coordinating to determine where, when and how much stover can be harvested for ethanol uses without harming the soil. His collaborators on the Renewable Energy Assessment Project (REAP), as it's called, include scientists from 12 other ARS locations, state universities and the U.S. Department of Energy.

Science Daily, July 9, 2007