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Selecting and Applying Cesium‐137 Conversion Models to Estimate Soil Erosion Rates in Cultivated Fields
Author(s) -
Li Sheng,
Lobb David A.,
Tiessen Kevin H.D.,
McConkey Brian G.
Publication year - 2010
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2009.0144
Subject(s) - erosion , environmental science , soil science , tillage , hydrology (agriculture) , geology , geotechnical engineering , agronomy , paleontology , biology
The fallout radionuclide cesium‐137 ( 137 Cs) has been successfully used in soil erosion studies worldwide. However, discrepancies often exist between the erosion rates estimated using various conversion models. As a result, there is often confusion in the use of the various models and in the interpretation of the data. Therefore, the objective of this study was to test the structural and parametrical uncertainties associated with four conversion models typically used in cultivated agricultural landscapes. For the structural uncertainties, the Soil Constituent Redistribution by Erosion Model (SCREM) was developed and used to simulate the redistribution of fallout 137 Cs due to tillage and water erosion along a simple two‐dimensional (horizontal and vertical) transect. The SCREM‐predicted 137 Cs inventories were then imported into the conversion models to estimate the erosion rates. The structural uncertainties of the conversion models were assessed based on the comparisons between the conversion‐model‐estimated erosion rates and the erosion rates determined or used in the SCREM. For the parametrical uncertainties, test runs were conducted by varying the values of the parameters used in the model, and the parametrical uncertainties were assessed based on the responsive changes of the estimated erosion rates. Our results suggest that: (i) the performance/accuracy of the conversion models was largely dependent on the relative contributions of water vs. tillage erosion; and (ii) the estimated erosion rates were highly sensitive to the input values of the reference 137 Cs level, particle size correction factors and tillage depth. Guidelines were proposed to aid researchers in selecting and applying the conversion models under various situations common to agricultural landscapes.