Background

On sloped agricultural fields, water and sediment can be transported downhill as runoff and erosion. This process can cause losses of valuable top soil material, water resources for plant availability, and nutrients as well as transport of plant protection products (PPP) into adjacent surface water bodies. In the European and the US risk assessment for the registration of PPP, runoff and erosion are numerically calculated with the simulation model PRZM which uses the USDA runoff curve number (CN) concept for the water movement. Results from runoff field trials were used to estimate the effect of dedicated management practices in terms of mitigating runoff and erosion, i.e. creating micro-dams between the ridges of potato fields or in maize cultivation on model input parameters.

Results

Application of different cultivation and tillage techniques (micro-dams/bunds) showed a consistent decrease of the measured quantities of runoff, erosion, and PPP transport as well as of the calculated CN and predicted environmental concentrations in surface water. The results presented here support the approach to quantitatively consider in-field risk mitigation measures (if applied) in the context of regulatory surface water exposure calculations, as proposed by the SETAC MAgPIE workshop.

Conclusion

Based on these data, a robust case can be made to consider innovative runoff mitigation for risk assessment purposes by, e.g. lowering the CN in the exposure scenarios. In the assessment presented herein, an average decrease in the mean of the derived CN of 86 of 21 points (± 11, 10th percentile: 12) for potatoes could be derived. For maize, the mean calculated CN of 73 was lowered on average by 3 points.

中文翻译：

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在监管风险评估中考虑风险管理实践：评估微型水坝的田间试验，以通过地表径流和土壤侵蚀减少农药的运输

背景

在倾斜的农田上，水和泥沙会随着径流和侵蚀而下坡运输。此过程可能导致宝贵的表层土壤物质，植物可用水资源和养分流失，以及植物保护产品（PPP）进入相邻地表水体的运输。在欧洲和美国的PPP注册风险评估中，径流和侵蚀是使用PRZM模拟模型进行数值计算的，该模型使用USDA径流曲线数（CN）概念进行水的运动。径流田间试验的结果被用于评估专门管理措施在减少径流和侵蚀方面的效果，即在模型输入参数上在马铃薯田间垄之间或在玉米栽培中创建微坝。

结果

应用不同的耕作和耕作技术（微坝/外滩）显示，径流量，侵蚀和PPP运输量的测算量以及所计算的CN和地表水中预测的环境浓度均不断降低。如SETAC MAgPIE研讨会所建议的，此处呈现的结果支持在监管地表水暴露计算的背景下定量考虑现场风险缓解措施（如果应用）的方法。

结论

基于这些数据，可以通过例如降低暴露场景中的CN来为风险评估目的考虑创新性径流缓解的可靠案例。在本文介绍的评估中，可以得出土豆的CN平均值平均下降了21点（±11，第10个百分位数：12），平均值为86。对于玉米，平均计算的CN为73，平均降低了3点。