Research Program Area: Climate Change
Nitrous oxide (N2O) is a potent GHG, comprising about 3 percent of California's GHG inventory in 2015. Emissions from agricultural soils represent the main source of N2O in California, contributing more than 5.8 metric million ton of CO2 equivalent (MMT CO2E) or 50 percent of total N2O emissions. Emissions of N2O from agricultural soils are closely related to soil nitrogen (N) content, but can be affected significantly by environmental factors such as soil organic carbon content and soil water content. Therefore, it is possible to mitigate N2O emissions by best management practices that alter environmental conditions. Numerous studies have demonstrated that N2O emissions from agricultural soils can be reduced effectively by various management practices. However, to assess mitigation potentials in a quantitative manner under diverse cropping systems and farming management practices, a process-based modeling tool would be required that is capable of simulating environmental impacts in complex agroecosystems. This project refined an existing model, DeNitrification DeComposition (DNDC), and produced such a quantitative tool, which can be used to estimate mitigation potentials of N2O in California specific conditions. The tool has also been adopted to develop N2O emission estimates from California croplands for the 2015 California GHG inventory. Simulation of mitigation scenarios using the tool indicated that subsurface drip and surface drip irrigation, reduction of N rate by 15 percent plus nitrification inhibitor, and planting non-legume cover crops are the most effective mitigation measures, which could reduce statewide N2O emissions by 59 percent, 41 percent, 28 percent and 22 percent, respectively, compared to Business As Usual (BAU) scenarios in California.
For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753
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