Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, The Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, 050021, Hebei, China.
School of Mathematics and Science, Hebei GEO University, 136 Huai'an Road, Shijiazhuang, 050031, Hebei, China.
J Environ Manage. 2023 Nov 1;345:118667. doi: 10.1016/j.jenvman.2023.118667. Epub 2023 Jul 27.
Nitrogen (N) is essential for agricultural production. However, too much N can pollute waters. The Chinese government published several policies to reduce N losses from agricultural production to waters since 2015, which may influence river export of N to reservoirs and lakes and their pollution sources. This study aimed to quantify the trends of river export of N to five reservoirs in the Haihe basin and analyze the main sources of this N pollution from 2012 to 2017. This was done by upscaling the MARINA-Lakes (Model to Assess River Inputs of Nutrients to lAkes) model to the Haihe basin, including 22 sub-basins. From 2012 to 2017, river export of total dissolved nitrogen (TDN) to the Haihe reservoirs decreased by 11-51%, associated with a decreased contribution of point sources and an increased contribution of diffuse sources for the whole study area Sub-basins draining into Reservoir Pan-Da contributed over one-third to the total TDN export by rivers in 2012 and 2017. The share of diffuse sources in river export of TDN to the Guanting reservoir reached 63% in 2017. Among the TDN diffuse sources, the contribution of animal manure (a diffuse source) to river export of diffuse TDN increased to 28%, 25%, and 23% for the sub-basins of Reservoir Miyun, Pan-da, and Guanting from 2012 to 2017, respectively. Among the TDN point sources, direct manure discharges were the main contributors to the river export of point TDN to the Haihe reservoirs in 2012. By 2017, direct discharges of untreated human waste became another important point source, especially for the Lake Baiyangdian and Reservoir Gang-Huang. This study concludes the need for specific agricultural N management options for different reservoirs of the Haihe basin.
氮（N）是农业生产的必需品。然而，过量的 N 会污染水体。自 2015 年以来，中国政府发布了多项政策，以减少农业生产中 N 的流失到水体中，这可能会影响河流向水库和湖泊的 N 输出及其污染源。本研究旨在量化 2012 年至 2017 年海河流域五个水库的河流 N 输出趋势，并分析其 N 污染的主要来源。通过将 MARINA-Lakes（湖泊输入营养物质模型）模型扩展到包括 22 个子流域的海河流域，来实现这一目标。2012 年至 2017 年，海河流域向水库的总溶解氮（TDN）输出减少了 11-51%，与整个研究区点源的贡献减少和非点源的贡献增加有关。2012 年和 2017 年，排入潘大水库的子流域对河流总 TDN 输出的贡献超过三分之一。2017 年，非点源在 Guanting 水库 TDN 输出中的比例达到 63%。在 TDN 非点源中，2012 年至 2017 年，来自密云、潘大、官厅水库子流域的动物粪便（非点源）对 TDN 非点源河川输出的贡献率分别增加到 28%、25%和 23%。在 TDN 点源中，2012 年直接粪肥排放是海河流域向水库河川输出点 TDN 的主要贡献者。到 2017 年，未经处理的人类粪便直接排放成为另一个重要的点源，特别是对白洋淀和岗黄水库。本研究得出结论，需要为海河流域的不同水库制定具体的农业 N 管理方案。
