Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2002
Publication Date: 1/1/2003
Citation: ZHANG, X.C., NEARING, M.A., POLYAKOV, V.O., FRIEDRICH, J.M. USING RARE-EARTH OXIDE TRACERS FOR STUDYING SOIL EROSION DYNAMICS. SOIL SCIENCE SOCIETY OF AMERICA JOURNAL. 2003. v. 67(1). p. 279-288. Interpretive Summary: Soil erosion deteriorates land, soil, and water resources, and therefore adversely affects environmental quality and sustainability of agricultural production. Development of effective soil erosion control measures requires a thorough understanding of soil erosion mechanisms, that is, how soil materials are detached, transported, and deposited along a hill slope or within a watershed. The purpose of this work was to test the feasibility of using non-hazardous Rare Earth Element oxide lanthaide for tracing sediment movement along a hill slope. Results indicate that Rare Earth Element oxide tracers are capable of tracing sediment movement and redistribution within a field or hill slope with fairly good accuracy. This tracing technique may provide erosion scientists a unique means of understanding how soil is eroded, transported, or deposited within a field. This information is also useful to soil conservationists for developing or evaluating new erosion control measures. For practical applications, the tracing technique can be used to pinpoint sediment source areas within a hill slope or watershed of special interests.
Technical Abstract: Most soil erosion data are spatially averaged, which provide limited value in understanding soil erosion dynamics. Spatially-distributed and dynamically-varied erosion data are needed for better understanding erosion processes and thorough evaluation of process-based erosion prediction models. The objectives of this study were to examine the feasibility of the direct-mixing of Rare Earth Element (REE) oxides with soil materials for tracing soil erosion at a plot scale and to further explore the potential of using this tracing technique for studying soil erosion dynamics. Five REE oxide powders were mixed with a Camden silt soil (fine, silty, mixed, mesic Typic Hapludalt) at five slope positions. Six rains (60 mm/h for the first four rains and 90 mm/h for the last two) were applied to a 4 by 4 m soil bed at 10% slope. Runoff was collected during rains and the surface soil was sampled after each rain. All samples were extracted for REE with a quick acid leaching method and the extracts were analyzed by inductively coupled plasma-mass spectrometry. The average relative error of REE-estimated sediment discharge relative to measured total across 6 rains was 14.5%. Our results demonstrate that the REE tracing technique is feasible, being capable of producing both spatially and temporally distributed erosion data. This technique has the potential to bring about new perspectives to soil erosion research.