Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2004
Publication Date: July 15, 2005
Citation: Franzluebbers, A.J. 2005. Soil organic carbon sequestration and agricultural greenhouse gas emissions in the Southeast USA. International Journal of Soil and Tillage Research. 83:120-147. Interpretive Summary: Agriculture in the southeastern USA can be highly productive due to the warm-moist climatic conditions. Storage of organic carbon in soil is an important component of soil fertility, but also plays a role as a mechanism to help reduce carbon dioxide concentration in the atmosphere. This paper was compiled by a scientist at the USDA Agricultural Research Service in Watkinsville Georgia and reviews data available on carbon storage in soil and greenhouse gas emissions from agricultural management systems in the southeastern USA. Management systems that stored more carbon in soil were conservation tillage, utilization of cover crops, more complex crop rotations, optimum nitrogen fertilization, perennial grass pastures, and moderate grazing of pastures. Farmers, scientists, and environmental organizations can benefit from this information to guide more effective implementation of management systems to meet multiple goals of profit, production, and environmental protection.
Technical Abstract: This paper is a review and synthesis of literature pertaining to soil organic C sequestration and greenhouse gas emissions from agricultural activities in the southeastern USA. With conventional tillage as a baseline, soil organic C sequestration with no tillage was 0.42 Mg/ha/yr. Combining cover cropping with no tillage enhanced soil organic C sequestration (0.53 Mg/ha/yr) compared with no tillage and no cover cropping (0.28 Mg/ha/yr). Soil organic C sequestration could be optimized at 0.24 Mg/ha/yr with application of 107 kg N/ha/yr on N-responsive crops, irrespective of tillage management. In longer term studies (521 years), poultry litter application led to soil organic C sequestration of 0.47 Mg/ha/yr. Land that was previously cropped and converted to forages sequestered soil organic C at a rate of 1.08 Mg/ha/yr. By expanding research on soil organic C sequestration into more diverse pasture and manure application systems and gathering much needed data on methane and nitrous oxide fluxes under almost any agricultural operation in the region, a more complete analysis of greenhouse gas emissions and potential mitigation from agricultural management systems would be possible.