CESIUM-137, SOIL, AND SOIL ORGANIC CARBON REDISTRIBUTION ON THE LANDSCAPE

Authors: Ritchie, Jerry; McCarty, Gregory; Venteris, Erik

Submitted to: IAEA-FAO Research Coordination Meeting for CRP
Publication Type: Abstract Only
Publication Acceptance Date: 9/24/2004
Publication Date: 10/2/2004
Citation: Ritchie, J., McCarty, G., Venteris, E. 2004. Cesium-137, soil, and soil organic carbon redistribution on the landscape [abstract]. Abstract of the 2nd Research Coordination Meeting of the IAEA/FAO Co-ordination Research Project. p. 25.

Interpretive Summary:

Technical Abstract: Patterns of soil organic carbon (SOC) vary widely across the landscape leading to large uncertainties in the SOC budget of agricultural systems especially for landscapes where water, tillage, and wind erosion redistributes soil and SOC across the landscape. It is often assumed that soil erosion results in a loss of SOC from the agricultural ecosystem, but recent studies indicate that soil erosion and its subsequent redistribution within fields can stimulate carbon sequestration in agricultural ecosystems. This study investigates the relationship between SOC and soil redistribution patterns on agricultural landscapes. Soil redistribution (erosion and deposition) patterns were estimated in three tilled agricultural fields using the fallout 137Cesium technique. Cs-137 and SOC concentrations of upland soils are significantly correlated in our study areas. Soils in upland areas (eroding) have significantly less Cs-137 and SOC than soils in deposition areas. SOC decreased as gradient slope increases and soils on concave slopes had higher Cs-137 and SOC than soils on convex slopes. These data suggest that soil redistribution patterns and topographic patterns may be used to help understand 137Cs and SOC dynamics on the landscape. Different productivity and oxidation rates of SOC of eroded versus deposited soils also contribute to SOC spatial patterns. However, the strong significant relationships between soil redistribution, Cs-137 , and SOC concentrations in the upland soil suggest that soils and organic matter are transported along similar physical pathways in these systems. Our study also indicates that landscape position is important for understanding soil movement and redistribution patterns within a field or watershed. Such information can help develop or implement management systems to increase SOC in agricultural ecosystems.