Evaluating the impact of agricultural practices and climate change by using 137Cs resampling to assess recent changes in soil redistribution rates in northern Spain

Abstract

Climate change and anthropogenic activities, mainly agricultural practices, significantly intensify denudation processes. A new strategy to improve the application of ¹³⁷Cs technique has been tested and validated in an upland agroecosystem in north Spain to provide information on changing soil redistribution rates between multiple periods. For the first time in Spain, the ¹³⁷Cs resampling approach, which requires repeated soil sampling programs, has been applied in a representative Mediterranean mountainous landscape. The toposequence selected for this study characterized by rangeland and cultivated soils has maintained the land cover and land uses between the two sampling campaigns, 2003 and 2016. We identified specific processes of erosion and deposition occurring in sectioned soil profiles over the time interval of this study. As the land use has been maintained for most of the sampling sites, the change in redistribution rates recorded in the soil profiles may be associated with a shift in rainfall patterns over the study period. However, change in land management with impact on soil redistribution has been successfully identified in two sites by applying the resampling approach. The results allow a better understanding of changes in soil mobilization and the possibility to evaluate the influence of agricultural management and climate variability on soil erosion. The procedure described in this study must be seen as a promising application of ¹³⁷Cs measurements in soil erosion investigations associated with climate change.