|Prior, Stephen - Steve|
Submitted to: International Soil Tillage Research Organization Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2000
Publication Date: 7/1/2000
Citation: Prior, S.A., Dorman, B.G., Raper, R.L., and Schwab E.B. 2000. Influence of fall and spring tillage on soil CO2 efflux from a loamy sand soil in Alabama. In Proc., International Soil Tillage Research Organization, 15th International Conference, July 2-7, 2000, Fort Worth, TX. 10 pp. Interpretive Summary: Tillage operations can influence loss of carbon from soil. Our goal was to evaluate CO2 flux patterns as affected by time of tillage operations and different tillage implements. Differences in CO2 flux patterns were related to increased soil disturbance. These results indicate that selecting tillage implements that minimize disturbance of residue and underlying soil during fall operations could conserve soil carbon, however such considerations during spring tillage operations would not substantially reduce soil carbon loss.
Technical Abstract: Management decisions that affect tillage intensity and the amount and placement of residues can influence soil C storage, thereby representing a viable strategy to help mitigate the rise in atmospheric CO2. However, information on seasonal CO2 flux patterns as affected by degree of soil disturbance/residue mixing and time of tillage operations are lacking. An experiment was conducted following a grain sorghum [Sorghum bicolor (L.) Moench.] crop on a Norfolk loamy sand (Typic Kandiudults; FAO classification Luxic Ferralsols) in east-central Alabama (USA) to characterize soil CO2 flux patterns as affected by tillage tool type [disk (DK), high residue field cultivator (FC), and no-till (NT)] and time of soil disturbance (i.e., fall and spring). Soil CO2 efflux was assessed immediately following fall tillage and periodically up to and including planting operations; likewise, these measures were also taken in the spring after imposing tillage treatments on another set of undisturbed plots. Concurrent measures were also made on NT plots. Increased CO2 efflux was related to degree of soil disturbance attributed to fall tillage; losses were similar for the FC and NT treatment and the highest loss occurred for DK treatment; cumulative flux estimates also reflected such differences. With spring tillage, loss of CO2 for the NT and DK treatment were similar, while the FC treatment exhibited a slightly lower loss. Results suggest that selection of fall tillage equipment that maintains surface residue and minimizes soil disturbance could help reduce CO2 loss. However, such considerations for spring tillage operations would not result in a substantial reduction in CO2 loss.