抚仙湖尖山河小流域山地典型地类非点源污染特征与分析

通过在尖山河小流域建立径流场.在自然降雨条件下采集水样,检测分析地表径流中各污染物的浓度,研究自然状态下和人为干扰下山地不同地类污染物的输出量,探讨高原湖泊山地非点源污染的特征与规律.研究结果表明:研究区内各地类产流量的关系是坡耕地>人工林>灌草丛>次生林,各地类产沙量大小关系是坡耕地>人工林>次生林>灌草丛,产流量与降雨量相关性更为显著;次生林、坡耕地、灌草丛、人工林4种土地类型产流的总无机氮输出量平均值分别为0.94 mg·m-2、19.70mg·m-2、1.74 mg·m-2、17.22 mg·m-2,总磷平均值分别为0.32mg·m-2、3.58 mg·m-2、1.12 mg·m-2、2.85 mg·m-2;产沙过程中单位面积水解氮输出量平均值为0.41 mg·m-2、7.17 mg·m-2、0.89 mg·m-2、0.23 mg·m-2,速效磷平均值为0.04 mg·m-2、1.14 mg·m-2、0.03 mg·m-2、0.02 mg·m-2;产流过程中输出的污染物大于产沙过程中的输出量,尖山河小流域农业非点源污染控制应以控制产流污染物为主.

The characteristics and analysis of non-point pollution in different land categories in small watersheds in the Jianshan River of Fuxian Lake

In order to discover the characteristics and rules that govern non-point source pollution in a plateau lake in Yunnan,rainfall samples from different land use types were collected and analyzed under natural and man-made interference conditions.The results showed that the runoff yield in different regions sequentially decreased from sloped farmland to planted forest,shrub-grassland and secondary forest.The sediment yield also showed a significant reduction,from sloped farmland to planted forest,secondary forest and shrub-grassland areas.The runoff yield showed significant correlations with the rainfall.For secondary forest,sloped farmland,shrub-grassland,and planted forest,the average outputs of total inorganic nitrogen in the runoff yield were 0.94 mg·m^-2,19.70 mg·m^-2,1.74 mg·m^-2,17.22 mg·m^-2,respectively.The average values of total phosphorus were 0.32 mg·m^-2,3.58 mg·m^-2,1.12 mg·m^-2,2.85 mg·m^-2,and the average outputs of hydrolyzed nitrogen in sediment were 0.41 mg·m^-2,7.17 mg·m^-2,0.89 mg·m^-2,0.23 mg·m^-2,while the available phosphorus values were 0.04 mg·m^-2,1.14 mg·m^-2,0.03 mg·m^-2,0.02 mg·m^-2,respectively.The pollutant output in runoff was larger than in sediment.Thus reducing the contaminants in runoff of the Jianshan river is critical to non-point pollution control.