珠溪河流域土地利用变化对面源磷污染的影响研究

探讨土地利用类型变化对磷、泥沙负荷以及截留能力的影响,为制定珠溪河流域面源磷污染治理措施提供重要支撑,也为鄱阳湖流域磷污染精准防治提供科学依据。基于2010年和2018年土地利用数据,采用SWAT模型对珠溪河流域面源磷负荷、泥沙负荷以及径流进行了模拟研究,并结合水文水质实测数据对模型的模拟结果进行评价。结果表明:相关系数R ²和Nash-Suttclife模型效率系数E _NS均满足SWAT模型在研究区的适用要求;泥沙与总磷的负荷强度与耕地、建设用地的覆盖率呈正相关,与林地、草地的覆盖率呈负相关,且总磷负荷强度与泥沙负荷强度有较高的重合性;2010年、2018年土地利用数据的总磷、泥沙年均入河系数分别为0.535、0.736和0.558、0.752,2个时期的泥沙与总磷入河系数中北部大于南部。控制农业生产和农村生活的污染物排放是减少面源污染的重要措施,进行退耕还林或退耕还草能有效截留污染物质以及起到防沙固土的作用。

Impact of Land Use Change on Phosphorus Non-Point Source Pollution in Zhuxi River Basin

Water quality dynamics in a river is closely related to land use in the river′s watershed.Pollutants resulting from agricultural planting,livestock and poultry culture,and rural domestic sewage enter the lake and streams in the form of non-point source pollution through different surface loading mechanisms.In recent years,the impact of land use change on non-point source pollution has received increased national and international attention.In this investigation,Zhuxi River of Wannian County in Jiangxi Province was selected for a case study on the impacts of land use change on phosphorus and sediment loading,and the interception capacity of the river basin.Based on land-use data in 2010 and 2018,the soil and water assessment tool(SWAT)model was used to simulate non-point source phosphorus pollution,sediment load and runoff in the Zhuxi River basin for the period 2010-2018.The simulation results were then evaluated using field measurements of hydrology and water quality.The aim of study was to provide a scientific basis for more precise targeting of control measures to reduce phosphorus pollution in Zhuxi River,as well as the formulation of non-point source phosphorus pollution control measures in the Poyang Lake basin.Correlation coefficients(R^( 2))and the Nash-Sutcliffe efficiency coefficient(E _NS)show that the SWAT model had high simulation accuracy in the Zhuxi River basin and the model was applicable.The load intensity of sediment and total phosphorus was positively correlated with coverage by farmland and settlement land,negatively correlated with coverage by forest and grassland,and the loading intensities of total phosphorus and sediment were highly correlated.The average annual loss rate of total phosphorus and sediment in 2010 and 2018 were,respectively,0.535,0.736 and 0.558,0.752.The loss rate of sediment and total phosphorus in the two periods were higher in the northern and central areas than in the southern river basin.Controlling the discharge of pollutants from agricultural production and rural life is important for reducing non-point source pollution.Conversion of farmland to forest or grassland can effectively intercept pollutants and play a role in preventing sand and soil erosion.