Establishing reference inventories of 137Cs for soil erosion studies: Methodological aspects

The radiocaesium technique has become an attractive methodology for quantifying long-term average soil erosion and accumulation rates. It is based on comparing the Cs-137 inventory in soils of a site which is suspected to be affected by soil redistribution to that of an adjacent undisturbed reference site. A major complication arises from the spatial variability of Cs-137 generally present even at small areas of <1 ha. In this paper we present statistically based procedures that efficiently allow to discriminate between soil erosion and pure spatial variation of Cs-137. We systematically explore the effect of study design and spatial variability of Cs-137 on the sensitivity of the radiocaesium technique for soil erosion studies. The procedures and simulation results presented assist (i) in checking whether the sensitivity of the Cs-137 technique is adequate for an intended study, and (ii) in developing an optimal study design. In addition it is shown that some of the statistical criteria proposed in the literature for discriminating soil redistribution from Cs-137 variability show high error risks and should be avoided. (C) 2013 Elsevier B.V. All rights reserved.