Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/5/2004
Publication Date: 11/16/2004
Citation: Liebig, M.A., Gollany, H.T. 2004. Sequestering carbon in cropland: Effects of management in semiarid regions of northwestern USA and western Canada. p. 32-36. IN: Proc. of the Alberta Reduced Tillage Linkages, Direct Seeding Advantage 2004. 16-17 Nov. 2004, Nisku, Alberta, Canada. Interpretive Summary: Management practices that increase SOC in cropland can: a) mitigate atmospheric carbon dioxide increase and its contribution to global climate change, b) improve soil quality, and 3) increase crop yields. As a result, benefits from soil carbon sequestration are accrued across multiple spatial scales by both agricultural producers and society. Recognition of cropland as a significant carbon sink and development of public and/or private reimbursement mechanisms for carbon sequestration can enhance adoption of improved management practices on cropland. Within semiarid regions of northwestern USA and western Canada, continuous cropping with no-till appears to be the most effective dryland cropping system to increase soil organic carbon. The agronomic and environmental benefits associated with this cropping system improve agroecosystem performance, thereby increasing agricultural sustainability.
Technical Abstract: In semiarid regions of northwestern USA and western Canada, approximately one-third of soil organic carbon (SOC) has been lost as a result of conversion of grassland to cropland. This loss equates to a decrease in soil organic matter of about 2% at the field-level, or 1,850 million metric tons C at the region-level. To counteract this decline in SOC, management systems known to sequester C need to be identified and employed. Continuous cropping management, used in concert with no-till, is the most effective dryland cropping system to increase SOC in northwestern USA and western Canada. The rate of SOC accretion for continuous cropping with no-till averaged 0.27 Mg C/ha/yr for the region. This management system creates a more resilient soil resource through its effect on soil quality, as shown through improvements in nutrient cycling potential, erosion resistance, and water absorption and transfer. An improvement in soil quality, in turn, increases crop yield, thereby enhancing global food security. The agronomic and environmental benefits associated with continuous cropping with no-till improve agroecosystem performance, thereby increasing agricultural sustainability. [GRACEnet Publication]