Franzluebbers, Alan (USDA-ARS, Watkinsville, GA, 30677; Phone: 706-769-5631; Fax: 706-769-8962; Email: afranz@uga.edu)

Soil Organic Carbon Sequestration in Pastures of the Southeastern USA: Knowledge and Gaps

A.J. Franzluebbers *

Agricultural land in the southeastern USA encompasses approximately 45 Mha, of which 19 Mha is devoted to pasture. This extensive resource has the potential to sequester soil organic C (SOC), especially following historical conversion of land, first from native forest to intensively cultivated cropland and more recently from intensively cultivated cropland to pastureland. This paper reviews recent research reporting SOC changes with pasture management and identifies significant gaps in our knowledge of how pasture management might affect SOC and emission of greenhouse gases. Management factors affecting SOC include land use, forage type, fertilization, and forage utilization. Establishment of perennial grass pastures could sequester SOC at rates of 0.2 to 1.5 Mg C/ha/yr, depending upon management variables. Although some information on SOC sequestration and greenhouse gas emission is available, there is a great need to conduct more research on the diversity of pasture systems relevant to agriculture in the southeastern USA.