Soil erosion models verification in a small catchment for different time windows with changing cropland boundary

Abstract

This paper presents very detailed studies of soil erosion within a small arable catchment located in the centre of the East European Plain. Sediment redistribution was estimated based on soil profile truncation, radiocesium methods and erosion modelling. WaTEM/SEDEM and State Hydrological Institute model were used for the evaluation of soil losses during rainfall and snowmelt, respectively. Evaluation of soil erosion and sediment redeposition was carried out taking into account historical changes in the cropland boundaries. Model estimates of soil losses from arable land are in good agreement with evaluations of erosion rates based on the results field method applications, taking into account the uncertainty of the methods. Erosion modelling made it possible to fairly plausibly estimate the decrease in soil erosion losses by approximately by a third as a result of a small (about 5%) reduction in the area of arable land in the studied catchment. The main disadvantage of applied erosion models were associated with the insufficient accuracy of estimates of the sedimentation volume and location deposition zones, mainly outside the arable land. The simulated net erosion for the entire catchment was underestimated by 3.5–4.5 times compared with field methods. This simulation block must be calibrated taking into account the regional coefficients of sediment transport in the bottoms of the dry valley network.