Abstract：
Water runoff and soil erosion by water from agricultural fields lead to a loss of water available for plant growth, loss of topsoil and transport of plant protection products (PPPs), hence constituting contaminant pathways to adjacent surface water. Several mitigation measures are used, including small earthen dams or depressions, referred to as micro-dams. This practice has been applied worldwide since the 1930s. In the regulatory exposure assessment for the registration of PPPs, runoff curve numbers (CNs) are used in the PRZM model to quantify runoff and the effect of mitigation measures. An overview of the pertinent literature is presented to enlarge the knowledge base to give robust recommendations for the inclusion of the practice in the regulatory exposure assessment of PPPs. Literature on micro-dams was collected here in a review of the reported results from field trials in terms of runoff, erosion, and PPP transport mitigation. Selected data were further evaluated to derive runoff CNs. From 21 studies with 252 individual setups and trials, we derived a geometric mean reduction of runoff of 62% (42%-90%); results for maize and potatoes only were 62% (53%-73%) and 81% (71%-93%), respectively. Erosion was reduced by 73% (60%-90%; maize: 75% [63%-88%]; potatoes 89% [83%-97%]). From 19 studies with 246 individual setups and trials, the geometric mean of the CN reduction is 11% (4%-25%; maize: 7% [3%-17%], potatoes: 14% [6%-36%]). For PPP transport (5 studies; 10 different PPP), a geometric mean reduction of 67% (48%-94%) was derived (maize: 56% [38%-81%; 3 studies; 10 PPP]; potatoes: 91% [1 study; 4 PPP]). The application of micro-dams provides considerable reductions and can therefore be factored into the environmental exposure assessment by using percent reductions of runoff, erosion, and PPP transport or lowering the runoff CN in numerical modelling.
摘要：
农田的水径流和土壤侵蚀导致植物生长可用的水流失，表土流失和植物保护产品(PPPs)运输，因此构成到邻近地表水的污染物路径。使用了几种缓解措施，包括小土坝或凹陷，被称为微型水坝。自1930年代以来，这种做法已在世界范围内得到应用。在PPP注册的监管暴露评估中，在PRZM模型中使用径流曲线数（CN）来量化径流和缓解措施的效果。对相关文献进行了概述，以扩大知识库，为将实践纳入PPP的监管暴露评估提供了强有力的建议。在这里收集了有关微型水坝的文献，以回顾从径流方面的田间试验报告的结果，侵蚀,和PPP运输缓解。对选定的数据进行了进一步评估，以得出径流CN。从21项研究和252项个人设置和试验中，我们得出径流的几何平均减少了62％（42％-90％）；玉米和马铃薯的结果仅分别为62％（53％-73％）和81％（71％-93％），分别。侵蚀减少了73％（60％-90％；玉米：75％[63％-88％]；马铃薯89％[83％-97％]）。从19项研究和246项个人设置和试验中，CN减少的几何平均值为11％（4％-25％；玉米：7％[3％-17％]，土豆：14%[6%-36%])。对于PPP运输(5项研究；10种不同的PPP)，几何平均减少67%(48%-94%)(玉米:56%[38%-81%;3项研究;10项PPP];马铃薯:91%[1项研究;4项PPP])。微坝的应用提供了相当大的减少量，因此可以通过使用径流减少百分比来考虑环境暴露评估，侵蚀,和PPP运输或在数值模拟中降低径流CN。
