149-1 Modeling Nitrous Oxide Emissions in Bioenergy Cropping Systems Using DNDC.

Poster Number 1708

See more from this Division: SSSA Division: Soil & Water Management & Conservation
See more from this Session: Developing Sustainable Bioenergy Cropping Systems: II

Monday, November 16, 2015
Minneapolis Convention Center, Exhibit Hall BC

Andrew R. McGowan, The Climate Corporation, San Francisco, CA, Miguel Arango, Colombian Corporation of Agricultural Research (Corpoica), Villavicencio, Colombia and Charles W. Rice, 2701 Throckmorton Hall, Kansas State University, Manhattan, KS
Abstract:
The 2007 Energy Independence Security Act mandates the production of 60 billion liters per year of cellulosic biofuel by 2022, which will be required to have life cycle assessment greenhouse gas (GHG) emissions at least 60% below those of gasoline/diesel. Emissions of nitrous oxide (N2O) could have a major impact on the GHG balance of biofuels. The multiple environmental and management factors driving N2O emissions make process-based models, like the DeNitrification DeComposition (DNDC) model, necessary to quantify these processes over large spatial and temporal scales. However, few studies have used DNDC to simulate N2O in bioenergy cropping systems. Therefore, the objectives of this study were to 1) use DNDC to model dedicated bioenergy crop growth in Manhattan, KS and 2) evaluate the ability of DNDC to predict N2O emissions under different bioenergy crops. DNDC crop parameters and field observations from the literature were used to develop initial crop parameters for corn, photoperiod-sensitive sorghum, switchgrass and miscanthus. DNDC was used to simulate biomass production of these crops and was compared to measured data from a 7 year field trail in Manhattan, KS. DNDC was then used to model N2O emissions which were compared to field observations. Yield was poorly simulated by DNDC, with negative Nash-Sutcliffe model efficiency coefficients (ME) for all crops except switchgrass. Daily fluxes of N2O were successfully simulated in switchgrass only (ME = 0.43). Simulated annual N2O emissions were significantly different from measured estimates in 7 out of 16 crop-years. These preliminary findings suggest that calibration of crop and soil parameters is required to improve yield and N2O simulations in DNDC for the crops in this study.

See more from this Division: SSSA Division: Soil & Water Management & Conservation
See more from this Session: Developing Sustainable Bioenergy Cropping Systems: II

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