Research on GHG Emissions in Agricultural Ecosystems

This page last reviewed December 5, 2017


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California agriculture, with over 400 commodities, provides high quality food for Californians and people around the nation and the world. However, California croplands are also an important source of nitrous oxide (N2O), a potent greenhouse gas (GHG) causing climate change, contributing over 50% of the total N2O emission inventory in the State. Nitrous oxide is produced from soil through microbial processes that convert nitrogen from nitrogen fertilizers, manure, and crop residues into various nitrogen gases, including N2O. These microbial processes can be affected by environmental conditions which change constantly, leading to substantial uncertainties in N2O emission estimates.

ARB recognizes the complex nature of nitrous oxide emissions from agricultural soils, and has identified the need for “Collaborative Research to Understand N2O Emissions from Nitrogen Land Application” as an Early Action measure in its Initial AB 32 Scoping Plan. ARB, in collaboration with California Department of Food and Agriculture (CDFA), California Energy Commission (CEC), and California Department of Resources Recycling and Recovery (CalRecycle), has implemented a California N2O research program and convened an N2O Stakeholders Working Group to oversee statewide research activities investigating N2O and other greenhouse gas emissions from California agricultural lands. The research program aims to improve California’s N2O inventory and explore alternative management options that can cut N2O and overall greenhouse gas emissions from California croplands. The research program informs mitigation strategies and conservation management practices that will keep California’s agriculture prosper and sustainable.

Project Updates

N2O Stakeholder Meetings

ARB staff periodically hosts conference call meetings for the purpose of providing updates on N2O research activities being conducted by academia and funded by ARB, the California Department of Food and Agriculture (CDFA), the California Energy Commission (CEC) and CalRecycle.  Currently, ARB, CDFA, CEC and CalRecycle have funded ten N2O research projects through 2016. Links to research presentations and final reports are provided below.

Background, N2O Emissions Research 
N2O Emissions Research Projects

Baseline N2O Emissions from California Cropping Systems

  • Measuring and Modeling Nitrous Oxide Emissions from California Cotton, Corn and Vegetable Cropping Systems
    D. Goorahoo, CSU Fresno (CDFA funded, 2009-2014)
    Project was amended in 2012 to evaluate only cotton and tomato systems
    Research Proposal, presented Aug. 24, 2009
  • N2O Emissions from Application of Fertilizers in Agricultural Soils
    J. Six, UC Davis (CEC funded, 2009-2012)
    Research Proposal, presented Aug. 24, 2009
    Final Report, presented Sept. 12, 2011
  • Assessment of Baseline Nitrous Oxide Emissions in Response to a Range of Nitrogen Fertilizer Application Rates in Corn Systems
    M. Burger, UC Davis (ARB funded, 2013-2014)
    Research Proposal, presented Aug. 24, 2009
  • Assessment of Baseline Nitrous Oxide Emissions in California's Cropping Systems
    Combined Research Seminar, presented Nov. 28, 2012
Evaluating N2O Emissions Mitigations for Cropping Systems
N2O Emissions from Composting Systems
  • Research to Evaluate Nitrous Oxide (N2O) Emissions from Compost in Support of AB 32 Scoping Plan Composting Measure
    W. Horwath, UC Davis (CalRecyle funded, 2010-2014)
    Work Plan, presented May 17, 2010
Modeling N2O Emissions from Cropping Systems
  • Improving DNDC Modeling Capability to Quantify Mitigiation Potential of Nitrous Oxide from California Agricultural Soils
    J. Deng, Univ. of NH (ARB funded, 2014-2016)
    Research Overview, presented Jan. 29, 2014
    Final Report, Full Text, presented September 6, 2017


For more information, please contact Lei Guo at (916) 322-8097.

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