御临河流域农业面源污染负荷的研究

Research on Agricultural Non-Point Source Pollution Load in Yulin River Watershed

通过现场调查、现场采样和实验室分析方法进行流域农业面源污染的现状研究;采用GIS技术对重庆渝北区御临河流域地理要素进行分析,并提取地形参数;采用农业面源污染模型(AnnAGNPS)研究流域的农业面源污染负荷,标识农业面源污染负荷的空间分布和时间分布,并提出农业面源污染的控制措施.经模拟计算,御临河流域2000年产生泥沙沉积污染物为264 803.09 t;产生总氮为5 041.82 t,其中,吸附态氮为256.945 t,溶解态氮为4 784.875 t;产生总磷为123.897 t,其中,吸附态磷为67.334 t,溶解态磷为56.563 t.结果表明:农业面源污染与降雨量密切相关;农业面源污染在同一年内不同季节的污染物负荷相差悬殊,汛期浓度高,负荷量大.运用AnnAGNPS模型对御临河流域农业面源污染物输出总量进行模拟,模拟结果与实测结果在一定误差范围内基本一致,表明该模型在御临河流域的应用基本可行.

The situation on agricultural non-point source pollution was presented by the scene investigation, sampling and analysis in the laboratory. Geographical factors were analyzed by GIS and topographic parameters were extracted in Yulin River watershed in Yubei district of Chongqing. The agricultural non-point source pollution load and its spatial-temporal distribution were studied using the AnnAGNPS model. The countermeasures for agricultural non-point source pollution were discussed. With the AnnAGNPS model, load of sediment, total nitrogen and phosphorus were computed. Sediment load was 264 803.09 t. Total nitrogen load was 5 041.82 t, in which adsorbent nitrogen load and dissolvent nitrogen load were 256. 945 t and 4 784. 875 t. Total phosphorus load was 123. 897 t, in which adsorbent phosphorus load and dissolvent phosphorus load were 67. 334 t and 56. 563 t. The results show that agricultural nonpoint source pollution is closely related with rainfall. Pollution load in the different seasons of a year is different, and high density and heavy load will occur in flood season. Based on the AnnAGNPS model, the output load of pollutants for agricultural non-point source pollution in Yulin River watershed was simulated. The simulated results coincide with measured results within a certain error, which shows that this model is suitable in Yulin River watershed.