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United States Department of Agriculture

Agricultural Research Service

Title: Greenhouse Gas Contributions and Mitigation Potential of Agricultural Practices in Northwestern Usa and Western Canada

Authors
item LIEBIG, MARK
item Morgan, Jack
item Reeder, S
item Ellert, Ben - AGRIC & AGRI-FOOD CAN
item GOLLANY, HERO
item Schuman, Gerald

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 25, 2004
Publication Date: June 17, 2005
Citation: Liebig, M.A., Morgan, J.A., Reeder, S.J., Ellert, B.H., Gollany, H.T., Schuman, G.E. 2005. Greenhouse gas contributions and mitigation potential of agricultural practices in northwestern USA and western Canada. Soil & Tillage Research 83:25-52.

Interpretive Summary: Concern over human impact on the global environment has generated increased interest in estimating the effects of agroecosystems on greenhouse gas fluxes. In this regard, USDA-ARS has initiated a national research effort called GRACEnet (Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network), which seeks to improve understanding of agricultural carbon (C) sequestration and greenhouse gas emission reduction. To more effectively direct future research, a series of papers were prepared reviewing management effects on soil organic carbon (SOC) and carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes in cropland and rangeland for much of North America. This paper summarizes published research in the northwestern USA and western Canada. The summary indicates continuous cropping under no-tillage in the region consistently increases SOC at an average rate similar to the Intergovernmental Panel on Climate Change (IPCC) estimate for net annual change in C stocks from improved cropland management. Conversely, definitive estimates of C sequestration potential for rangelands are generally difficult to attain due to the diversity of plant communities, soils, and landscapes within rangeland ecosystems. Emissions of N2O tend to be greatest in irrigated cropland, followed by non-irrigated cropland, and rangeland. Both cropland and rangeland appear to have potential to act as a sink for atmospheric CH4, but the size of this C sink is difficult to determine. Researchers are challenged to address data gaps in CO2, N2O, and CH4 exchange between the atmosphere and cropland and rangeland in the northwestern USA and western Canada, as well as integrate such data to determine the net effect of agricultural land on radiative forcing.

Technical Abstract: Concern over human impact on the global environment has generated increased interest in quantifying agricultural contributions to greenhouse gas fluxes. In this regard, USDA-ARS has initiated a national research effort called GRACEnet (Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network), which seeks to improve scientific understanding of agricultural carbon (C) sequestration and greenhouse gas emission reduction. This paper summarizes published research reviewing management effects on soil organic carbon (SOC) and carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes in cropland and rangeland in the northwestern USA and western Canada. Review results indicate continuous cropping under no-tillage in the region consistently increases SOC at an average rate similar to the Intergovernmental Panel on Climate Change (IPCC) estimate for net annual change in C stocks from improved cropland management. Conversely, definitive estimates of C sequestration potential for rangelands are generally difficult to attain due to the diversity of plant communities, soils, and landscapes within rangeland ecosystems. Although there is generally poor geographical coverage throughout the region with respect to N2O and CH4 flux assessments, emissions of N2O tend to be greatest in irrigated cropland, followed by non-irrigated cropland, and rangeland. Both cropland and rangeland appear to have potential to act as a sink for atmospheric CH4, but the size of this C sink is difficult to determine. Researchers are challenged to address data gaps in CO2, N2O, and CH4 exchange between the atmosphere and cropland and rangeland in the northwestern USA and western Canada, as well as integrate such data to determine the net effect of agricultural land on radiative forcing. [GRACEnet Publication]

Last Modified: 9/29/2014
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