Monday, November 5, 2007 - 3:10 PM
109-5

Interactions of Cropping History and Residue Management Determine Acceptable Limits for Corn Stover Biofuel Harvest.

Keith Paustian1, Mark Easter2, Kendrick Killian2, Amy Swan2, Steve Williams2, and Karolien Denef3. (1) Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, (2) 200 West Lake Street/Central Rec., Colorado State University, Colorado State University, Natural Resource Ecology Lab, Fort Collins, CO 80523, (3) Ghent University, Gent, Belgium

We analyzed variable rates of corn (Zea mays L.) stover removal from center-pivot irrigated corn in western Nebraska to assess impacts on soil carbon maintenance, soil erosion and net greenhouse gas emissions of stover-to-ethanol production. Field level simulation analyses showed significantly higher recovery rates of stover under no-till conditions compared to reduced and conventional tillage, to maintain similar soil C stock levels. However, management history, specifically time under irrigation, had the largest influence on soil C response to varying levels of stover removal. Regional scale analyses were done for a 12 country region surrounding Imperial, NE to estimate soil C, erosion and net greenhouse gas emissions for different stover supply levels.