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United States Department of Agriculture

Agricultural Research Service

Research Project: Mitigating Agricultural Sources of Particulate Matter and Greenhouse Gas Emissions in the Pacific Northwest

Location: Northwest Sustainable Agroecosystems Research

Title: Carbon storage and nitrous oxide emissions of cropping systems in eastern Washington: A simulation study

Authors
item Stöckle, Claudio -
item Higgins, Stewart -
item Kamanian, Armen -
item Nelson, Roger -
item Huggins, David
item Marcos, Javier -
item Collins, Harold

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2012
Publication Date: September 1, 2012
Citation: Stöckle, C., Higgins, S., Kamanian, A., Nelson, R., Huggins, D.R., Marcos, J., Collins, H.P. 2012. Carbon storage and nitrous oxide emissions of cropping systems in eastern Washington: A simulation study. Journal of Soil and Water Conservation. 67(5):365-377.

Interpretive Summary: Conservation tillage is an agricultural strategy to help reduce atmospheric greenhouse gas (GHG) emissions such as nitrous oxide (N2O) and carbon dioxide (CO2). In agriculture, increases in soil organic C occur as carbon dioxide (CO2) is removed from the atmosphere while nitrous oxide emissions are primarily related to nitrogen fertilizer use. In eastern Washington we evaluated the long-term effects of conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) on soil organic carbon (SOC) storage and nitrous oxide emissions at three dryland and one irrigated location using the cropping systems simulation model CropSyst. Conversion of CT to NT produced the largest relative increase in SOC storage where increased rates of SOC storage ranged from 0.29 to 0.53 Mg CO2e ha-1 yr-1. The changes in SOC storage were less with lower annual precipitation, greater amounts of fallow and with changes from CT to RT. Simulated N2O emissions were not very different under CT, RT and NT. However, N2O emissions were sufficiently high to offset gains in SOC from RT and NT, indicating that improved N management in all systems could contribute to GHG mitigation. These results will be useful for wheat growers, NRCS, Conservation Districts, USEPA, scientists and the fertilizer industry as understanding the effectiveness of agricultural GHG mitigation strategies is critical for addressing climate change and managing soil sustainability.

Technical Abstract: Conservation tillage is an agricultural strategy to mitigate atmospheric greenhouse gas (GHG) emissions. In eastern Washington we evaluated the long-term effects of conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) on soil organic carbon (SOC) storage and nitrous oxide emissions at three dryland and one irrigated location using the cropping systems simulation model CropSyst. Conversion of CT to NT produced the largest relative increase in SOC storage (change in SOC, average yearly storage relative to CT) in the top 30-cm of soil where increased rates of change in SOC storage ranged from 0.29 to 0.53 Mg CO2e ha-1 yr-1. The change in SOC were less with lower annual precipitation, greater amounts of fallow and with changes from CT to RT. Overall, the change in SOC rate decreased from the first to the third decade after conversion from CT to NT or RT. Simulations of change in SOC for the conversion of CT to NT based on a 0–15-cm soil depth were greater than the change in SOC based on a 0–30-cm depth primarily due to differences among tillage regimes in the depth-distribution of C inputs and the resultant SOC characteristic with depth. Simulated N2O emissions, expressed as CO2 equivalent, were not very different under CT, RT and NT. However, N2O emissions were sufficiently high to offset gains in SOC from RT and NT, indicating that improved N management in all systems could contribute to GHG mitigation.

Last Modified: 10/24/2014
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