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United States Department of Agriculture

Agricultural Research Service

Title: Cesium-137 for Measuring Soil Erosion and Redeposition: Application for Understanding Soil Carbon

Author
item RITCHIE, JERRY

Submitted to: Advances in Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 1999
Publication Date: N/A

Interpretive Summary: The large size of the soil organic carbon pool makes it a key factor for understanding global carbon cycles. While there is great potential to sequester carbon in soil, it is necessary to know the mechanism of carbon loss from the soil to determine its fate in the environment. Studies have shown that the most important factors for understanding long-term carbon loss for soils are soil erosion or biological oxidation. There is little doubt that better estimates of soil redistribution on the landscape would improve our understanding of the soil organic carbon pool. Measurements of Cesium-137 redistribution across the landscape can provide a rapid and realistic estimates of soil redistribution on the landscape. This study reviews the applications of Cesium-137 for measuring in situ soil erosion and redeposition in a field and link these measurements to understanding soil organic carbon pools on the landscape.

Technical Abstract: Radioactive fallout Cesium-137 (Cs-137) can provide quantitative estimates of soil erosion and redeposition. This paper provides an overview of the use of the Cs-137 technique for estimating soil erosion and redeposition and examples of its potential for helping to understand soil organic carbon (SOC) pools. Since most SOC is in the soil layers most vulnerable to soil erosion, large amounts of SOC are redistributed along with the eroding soi particles while other SOC is exposed to oxidation process at the surface. Cs-137 was used to measure the erosion and redeposition of soil particles of the vulnerable layer. Erosion and redeposition of soil particles on transects upslope of a conservation practice site showed both erosion and deposition with a net accumulation measured. Assuming that SOC was uniformly distributed then a net accumulation rate of SOC has occurred also. However, since the redistribution of the soil particles would expose eSOC to a more oxidizing environment there could be a differential loss of soil particles and SOC. Cs-137 can give information on the redistribution of soil particles within the landscape unit and provide information on the loss of soil particles and SOC from the landscape unit.

Last Modified: 9/10/2014
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