Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 15, 2004
Publication Date: July 4, 2004
Citation: Ritchie, J.C., McCarty, G.W., Venteris, E.R., Kaspar, T.C., Owens, L.B., Nearing, M. 2004. Assessing soil organic carbon redistribution with fallout 137Cesium. In: Proceedings of Conserving Soil and Waterfor Society: Sharing Solutions, ISCO 2004-13th International Soil Conservation Organization Conference, July 4-9, 2004, Brisbane, Australia. 613:4. 2004 CDROM.
Patterns of soil organic carbon (SOC) vary widely across the landscape leading to large uncertainties in the SOC budget especially for agricultural areas where water and wind erosion redistributes soil across the landscape. This study was designed to determine SOC distribution patterns related to soil redistribution in four different physiographic regions of the United States. Soil redistribution (erosion/deposition) patterns were estimated using the fallout Cesium-137 technique in tilled agricultural fields in Maryland, Ohio, and Iowa. Grazed semiarid rangeland watersheds were sampled in Arizona. In an Iowa field, SOC had an order of magnitude difference in concentration (0.5 to 5%) and was significantly correlated (r2=0.68) with soil Cs-137 concentration and soil erosion/deposition rates. Sites of soil erosion in Iowa had significantly lower average concentrations of SOC (2.4%) than sites of soil deposition (3.4%). SOC was also significantly correlated with erosion rates calculated from Cs-137 in Ohio and Maryland fields although the r2 values were lower. Patterns of erosion and deposition for the semiarid watersheds showed the grassed watershed to have less erosion than the shrub watershed. These studies show the importance of understanding soil redistribution patterns within a field or watershed for understanding soil loss and SOC patterns and the potential for developing or implementing management systems to increase SOC in agricultural areas based on an improved understanding of patterns of soil movement.