A simple model of Cs-137 profile to estimate soil redistribution in cultivated stony soils

A main issue in soil erosion studies is to calibrate ¹³⁷Cs data to provide satisfactory estimates of erosion and deposition rates. The cultivation on steep slopes in some areas of the South Central Pyrenees results in serious affections to soils due to water erosion that mobilizes soil particles down slope. In the region, the intensive soil use including deforestation, overgrazing and extensive agriculture during the last centuries together with some characteristics of the soils such as poor development, thin soil profiles and high stone contents make them prone to erosion. A model based on ¹³⁷Cs profile is proposed to calculate erosion or sedimentation rates in these cultivated soils. The model uses parameters such as the volume of the fine fraction of the soils and the depth of cultivation calculated from the values obtained just from the soil sampling. Using a computer program the annual deposit of ¹³⁷Cs is simulated for an erosion or deposition rate of soil. To test the model, ¹³⁷Cs profiles of cultivated soils were collected at sampling sites located on temperate slopes in the Sierra de la Carrodilla (South Pyrenees) and experimental results were simulated with the model. The simulation results of the model were consistent with the experimental results of ¹³⁷Cs concentrations and inventories. The model offers a potential to describe the soil redistribution in stony soils and estimates of erosion and deposition rates can be calculated easily for a range of the most common soils found in Mediterranean environments.