|Abrahamson Beese, Deborah|
Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/22/2006
Publication Date: 7/22/2006
Citation: Abrahamson Beese, D.A., Norfleet, M.L., Causarano, H.J., Williams, J.R., Shaw, J.N., Franzluebbers, A.J. 2006. Simulating soil organic carbon sequestration in cotton production systems with EPIC and the soil conditioning index in the southeastern USA [abstract]. Soil and Water Conservation Society Annual Meeting, July 22-26, 2006, Keystone, Colorado.
Technical Abstract: Sequestration of soil organic carbon (SOC) in the southeastern USA is perceived as occurring at a relatively low rate, because of the inherent low SOC content of most agricultural soils. However, recent field estimates of SOC sequestration in conservation management systems suggest that the sequestration rate could be higher than in other regions of the country. We used the EPIC v. 3060 model and the soil conditioning index (SCI) to estimate long-term SOC storage at Temple TX, McColl SC, and Watkinsville GA using four management systems: (a) cotton (Gossypium hirsutum L.) with conventional tillage, (b) cotton with no tillage, (c) corn (Zea mays L.)-cotton rotation with no tillage, and (d) bermudagrass (Cynodon dactylon L.)-corn-cotton rotation with no tillage. All no-tillage systems used wheat (Triticum aestivum L.) as a cover crop. Simulated SOC sequestration averaged 0.46 Mg/ha/yr under the three no-tillage management systems and -0.03 Mg/ha/yr under conventional tillage with EPIC. The SCI also predicted a strong difference in SOC sequestration between conventional and no tillage. Differences in SOC sequestration among crop rotations were not readily apparent with EPIC, but were with SCI. Predictions of SOC sequestration with EPIC were related to the SCI, but not necessarily in a linear manner as previously suggested. Cotton lint yield with no tillage averaged 88% of yield with conventional tillage, but lint water-use efficiency was not different between tillage systems. Under the simulated management and environmental conditions selected, the SCI appears to be a valuable method for making reasonable, cost-effective estimates of potential SOC sequestration in the southeastern USA, although validations under actual field conditions are still needed.