|Del Grosso, Stephen - Steve|
Submitted to: American Geophysical Union
Publication Type: Other
Publication Acceptance Date: 2/2/2006
Publication Date: 2/9/2006
Citation: Del Grosso, S.J., Parton, W.J., Ojima, D.S., Deandelo, B.J., Rose, S. 2006. Global scale daycent model analysis of greenhouse gas mitigation strategies for cropped soils. American Geophysical Union. (Oral presentation at the annual meeting).
Technical Abstract: Conversion of native vegetation to cropland and intensification of agriculture typically results in increased greenhouse gas (GHG) emissions and NO3 leaching. Agriculture is responsible for ~50% and ~70%, respectively, of the anthropogenic emissions of CH4 and N2O. Agriculture is also the primary contributor of eutrophication of aquatic systems from nutrients that are runoff or leached from cropped fields into waterways. Regional and larger scale estimates of GHG emissions and NO3 leaching are usually based on IPCC emission factor methodology, which is associated with high uncertainty. Process based models, such as DAYCENT, are just beginning to be used for national inventories of GHG emissions. The methodology used to conduct DAYCENT global and regional scale simulations of three major crops (corn, soybean, wheat) under baseline and alternative management is described in detail by Ojima et al. in this session. We compared model generated baseline GHG emissions and N losses for irrigated and rainfed cropping with land use alternatives intended to reduce GHG emissions. Mitigation scenarios considered are: nitrification inhibitors, split fertilizer application, N fertilizer reduction, and no-till cultivation. Simulations suggest that use of nitrification inhibitors leads to the largest reduction in N losses (~10%) and conversion to no till can store C and further offset GHG emissions associated with agriculture. Reduced fertilizer resulted in lower N losses, but crop yields were also reduced. Use of nitrification inhibitors and split fertilizer application both led to increased (~6%) crop yields. Future simulations will explore interactions between different mitigation options.