Diffusive losses of nitrogen and phosphorus from agricultural areas have detrimental effects on freshwater and marine ecosystems. Mitigation measures treating drainage water before it enters streams hold a high potential for reducing nitrogen and phosphorus losses from agricultural areas. To achieve a better understanding of the opportunities and challenges characterising current and new drainage mitigation measures in oceanic and continental climates, we reviewed the nitrate and total phosphorus removal efficiency of: (i) free water surface constructed wetlands, (ii) denitrifying bioreactors, (iii) controlled drainage, (iv) saturated buffer zones and (v) integrated buffer zones. Our data analysis showed that the load of nitrate was substantially reduced by all five drainage mitigation measures, while they mainly acted as sinks of total phosphorus, but occasionally, also as sources. The various factors influencing performance, such as design, runoff characteristics and hydrology, differed in the studies, resulting in large variation in the reported removal efficiencies.

农业地区氮和磷的扩散损失对淡水和海洋生态系统有不利影响。在排水进入溪流之前对其进行处理的缓解措施具有减少农业区氮磷损失的巨大潜力。为了更好地了解海洋和大陆性气候中当前和新的缓解排水措施的机遇和挑战，我们审查了以下方面的硝态氮和总磷去除效率：（i）自由水面人工湿地;（ii）生物反应器反硝化，（ iii）受控排水，（iv）饱和缓冲区和（v）集成缓冲区。我们的数据分析表明，所有五种排水缓解措施都大大降低了硝酸盐的负荷，而它们主要是总磷的汇，但偶尔也可以作为来源。在研究中，影响性能的各种因素（例如设计，径流特征和水文状况）有所不同，导致报告的去除效率差异很大。