Monday, November 5, 2007
99-15

Carbon and Nitrogen Dynamics in Sustainable Biofuel Agroecosystems.

Cathryn Dunn1, Emily Heaton2, Stephen P. Long3, Frank Dohleman4, Kelly McConnaughay1, Kim Magrini5, Ronald Follett6, Eldor Paul7, and Sherri Morris1. (1) Biology Department, Bradley University, 1501 West Bradley Avenue, Peoria, IL 61611, (2) Ceres, Inc., Ceres, Inc., 1535 Rancho Conejo Boulevard, Thousand Oaks, CA 91320, (3) Departments of Plant Biology and of Crop Sciences, University of Illinois, Urbana-Champaign, 1201 W. Gregory Drive, Urbana, IL 61801, (4) University of Illinois-Urbana-Champaign, 1201 W. Gregory Dr., 379 ERML, Urbana, IL 61801, (5) National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO ý80401-3393ý, (6) USDA-ARS, USDA-ARS Soil Plant Nutrient Research, 2150 Centre Ave. Bldg. D Ste. 100, Fort Collins, CO 80526-8119, (7) Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523

Bio fuels will occupy an important acreage of worldwide production in the future. Some land will come from agriculture, and some will be from soils not now intensively cultivated. Since this is a new venture, it is imperative that we, as scientists, strive to ensure that this is done in the most environmentally friendly manner. We need to ensure that there is net C sequestration in the soil, a minimum of applied chemicals, no soil erosion and maximum ecosystem sustainability. This will include both wildlife and societal benefits involving effects on the landscape and bio diversity. Nitrogen must be an important planning-research component. There should be a closed N cycle that involves no loss of radiative N gases to the atmosphere, no leaching of N to groundwater and a closed cycle of movement of nutrients from the field to the processing plant back to the field to maximize nutrient efficiency. Our own studies with Miscanthus and switchgrass in Illinois show deep rooting of the Miscanthus, which has three to four times the production capacity of switchgrass. This produces sequestered C at depth and appears to mine mineral soil N from depth in former agricultural fields. Extended laboratory incubations and measurement of CO2 fluxes show a build up of the active and slow pool of carbon with an associated increase in soil N pools. Pyrolysis molecular beam mass spectrometry shows unique chemical soil constituents in the tested Miscanthus, switchgrass, and associated soybean fields and may be useful in measuring root production.