Evaluation of the effectiveness of mitigation measures to reduce pesticide inputs into surface water bodies via surface runoff and erosion

Abstract

<p>Surface runoff from agricultural fields is a major input pathway of pesticides into surface waters. The aim of this project was to i) analyze the effectiveness of various mitigation measures to reduce pesticide runoff and erosion inputs into surface waters, ii) assess the suitability of the measures found effective for use in the quantitative environmental exposure assessment for authorization of plant protection products (PPP), and iii) make recommendations how the potentially suitable measures could be applied in risk assessment of PPP in Germany. Following a literature analysis, 16 risk mitigation measures were presented to five experts for evaluation of effectiveness, cost-effectiveness, controllability, current distribution and dissemination potential. Measures finally selected for quantitative analysis belong to 3 groups: vegetative filter strips (VFS), soil conservation measures and micro-dams in row crops. Subsequently, the effectiveness of the recommended measures was evaluated based on experimental data using different statistical methods (e.g. CART, MLR, graphical methods).</p><p>The quantitative analysis confirmed the effectiveness of VFS and micro-dams. For soil conservation measures (especially mulch-till), the evaluated data showed highly variable results. This was partly caused by the heterogeneity of the experimental data, which also made it difficult to aggregate the results of different studies.</p><p>The following conclusions were drawn: Both VFS and micro-dams can be recommended for application in quantitative environmental exposure assessment for pesticides.  However, infiltration and sedimentation in VFS should be simulated with a mechanistic model such as VFSMOD. The effect of micro-dams can be modelled as a reduction of the runoff Curve Number (CN). The runoff modelling should be carried out with a model such as PRZM which adjusts the CN daily based on soil water content.</p>