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

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

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0.94mg.m-2、19.70mg.m-2、1.74mg.m-2、17.22mg.m-2,总磷平均值分别为0.32mg.m-2、3.58mg.m-2、1.12mg.m-2、2.85mg.m-2;产沙过程中单位面积水解氮输出量平均值为0.41mg.m-2、7.17mg.m-2、0.89mg.m-2、0.23mg.m-2,速效磷平均值为0.04mg.m-2、1.14mg.m-2、0.03mg.m-2、0.02mg.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.

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 O. 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.