亚热带区域农业面源污染流域源头防控机理与技术示范

日益剧增的农业面源污染使得亚热带流域环境可持续管理面临巨大挑战。亚热带红壤丘陵地区的丰富降水、复杂多样土地利用方式和高强度氮磷投入,导致了该地区水文过程、氮磷元素生物地球化学过程、以及氮磷污染物迁移转化规律的复杂性。从"十一五"至今,我们以亚热带丘陵区典型金井小流域为对象,研究建立流域多尺度环境监测系统,准确定量流域氮磷平衡特征,精确解析流域氮磷迁移规律与输出通量;构建以水文和氮磷过程为主要对象的分布式栅格流域生源要素管理模型(CNMM),制定流域氮磷环境安全控制标准,开发流域环境安全评价和污染源头防控决策支持系统;研发针对农田养分流失、分散型农村生活污水和养殖业废水的绿狐尾藻生态湿地消纳技术,探索农业氮磷减控关键途径,构建流域面源污染源头防控技术体系,并进行了大规模的推广应用与示范。这些结果将巩固和加强亚热带区域农业面源污染流域源头防控的应用基础研究,为实现流域环境的生态管理、质量恢复和生态系统服务功能提升提供理论依据。

Controlling mechanisms and technology demonstrations of agricultural non-point source pollution in subtropical catchments

Increasing agricultural non-point source pollution has brought great challenges to sustainable management of catchment environment in the subtropics. The heavy precipitation, diverse land use types, and large quantities of nitrogen and phosphorus input result in the complexity of hydrological processes, nitrogen and phosphorus biogeochemical mechanisms, and migration of nitrogen and phosphorus pollutants. Since the 11th Five-Year Plan, we choose the typical subtropical Jinjing catchment as the research object, established a multi-scale catchment environment observation system, quantified catchment nitrogen and phosphorus balance characteristics, determined nitrogen and phosphorus losses from paddy fields at different spatial scales and their relationship to catchment stream water quality and nutrient loadings. Constructed a new distributed grid catchment biogenic element management model (CNMM model), established catchment environment quality assessment and decision support system for agricultural non-point source pollution controlling. Developed ecological wetland technology of nitrogen and phosphorus retention for farmland runoff, dispersed rural domestic sewage, and livestock wastewater, explored key approaches for reducing agricultural nitrogen and phosphorus pollution, and established technology system for agricultural non-point source pollution controlling and popularized the system on a large scale. These results would consolidate and strengthen the application foundation of agricultural non-point source pollution controlling, and provide theoretical basis for ecological management, catchment environment quality restoration, and ecosystem service function improvement in subtropical catchments.