Evaluation of the impact of Catchment Sensitive Farming in reducing pesticide contaminants in English rivers

This research aimed to evaluate the effectiveness of Catchment Sensitive Farming (CSF) in mitigating pesticide pollution in two English river catchments (Ancholme and Wensum) using the Soil and Water Assessment Tool (SWAT) model. SWAT was used to simulate pesticide transport from agricultural fields to rivers, considering factors like climate, soil properties, and various management practices for five commonly used herbicides: 2,4-D, Flufenacet, Bentazone, Mecoprop, and Propyzamide. The model was calibrated and validated for flow, and pesticide concentrations were simulated using regional pesticide usage data. Comparisons were made between simulated and observed pesticide levels to assess the impact of CSF. The study also investigated the potential impacts of different mitigation strategies (such as conservation tillage, no-till, strip cropping and contour cropping) on pesticide levels in rivers. While SWAT showed promise in predicting the timing of contamination events, significant discrepancies were observed between simulated and observed pesticide concentrations, highlighting the limitations of this current model implementation for accurately capturing the complex processes of pesticide fate in agricultural landscapes. Future research should focus on refining model parameters, incorporating higher-resolution spatial data for pesticide application, and exploring other mitigation strategies such as vegetative filter strips. Despite these limitations, the study provides valuable insights into the potential of SWAT for assessing the impacts of agricultural best management practices on pesticide pollution and informing future environmental management strategies.