Alan Franzluebbers and John A. Stuedemann. USDA-ARS, 1420 Experiment Station Road., Watkinsville, GA 30677
Long-term estimates of soil organic C sequestration in pastures managed with different approaches are needed to help determine the magnitude and extent of greenhouse gas mitigation with agricultural management. We determined soil organic C content throughout a 12-year period, in which Coastal bermudagrass (Cynodon dactylon L.) was sprigged into abandoned cropland and grown as the dominant forage during early years of management. At the end of five years, Georgia-5 tall fescue [Lolium arundinaceum (Schreb.) Darbyshire] was interseeded into the dormant stand of bermudagrass to obtain a mixed stand of warm- and cool-season perennial forage. Forage was utilized as: (a) unharvested conservation reserve, (b) grazed intensely by cattle, (c) grazed lightly by cattle, and (d) hayed. To obtain nearly equivalent N application, pastures were fertilized biannually with either inorganic or poultry litter fertilizer. This paper describes the changes in soil organic C in response to fertilizer source applied to pastures in northern Georgia.