Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2008
Publication Date: 3/10/2008
Citation: Adler, P.R., Dell, C.J., Veith, T.L., Del Grosso, S.J., Parton, W.J. 2008. Greenhouse gas mitigation potential with cellulosic and grain bioenergy crops. Ecological Society of America Abstracts. p. 40 Interpretive Summary: An interpretive summary is not required.
Technical Abstract: The land use impacts, such as nitrous oxide (N2O) emissions and soil carbon sequestration, are associated with the largest changes in life cycle greenhouse gases from growing bioenergy crops. The biogeochemical model DAYCENT simulates fluxes of carbon (C) and nitrogen (N) between the atmosphere, vegetation, and soil. From weather, soil-texture class, and land-use inputs, DAYCENT simulates crop production, soil organic-matter changes, and trace-gas fluxes. The objectives of this study were to evaluate the ability of DAYCENT to simulate measured N2O emissions, the largest greenhouse gas source, and quantify life cycle greenhouse gas emissions from bioenergy cropping systems. Switchgrass, reed canarygrass, and a corn rotation with soybeans and alfalfa were grown in central Pennsylvania and N2O emissions were measured. Given the high variability of N2O fluxes in natural systems, DAYCENT captured the observed daily variability in N2O emissions and simulated the observed seasonal patterns within bioenergy crops and differences in annual mean emissions among systems reasonably well. Compared with the life cycle of gasoline and diesel, in the long-term, where soil C sequestration was assumed to no longer occur, ethanol and biodiesel from the corn-soybean-alfalfa rotation reduced net greenhouse gas emissions by 43%, reed canarygrass by 97%, and 110% for switchgrass. Higher yielding switchgrass cultivars further reduced the life cycle greenhouse gases associated with ethanol use.