韩江流域面源污染及与景观格局的关系

为了定量研究韩江流域的面源污染情况以及景观格局对污染的影响,建立了流域水文水质模型,并采用多元线性回归、冗余分析方法,探索景观指标与污染物质量浓度变化量的关系。结果表明:西部宁江流域地区的总氮质量浓度较高,最大值为3.91 mg/L;东部汀江流域地区总磷质量浓度较高,最大值为2.15 mg/L;流域总体水质呈恶化趋势;景观指标能解释81.7%的面源污染变化,且景观的面积越大,其组成格局可能比空间格局对水质的影响更大;林地的面积百分比与面源污染负相关,农田、城镇、草地景观则相反;城镇或农田等人类景观的斑块密度、形状指数等空间格局指标与污染物质量浓度负相关;旱地相比水田对面源污染的贡献更大;在研究区采用退草还林、农业结构调整等管理措施分别能够削减1.82%和4.63%的总氮负荷以及1.16%和7.31%的总磷负荷。

Non-point source pollution in Hanjiang River Basin and its relation with landscape pattern

In order to quantitatively study the non-point source pollution in the Hanjiang River Basin and the impact of landscape pattern on pollution, a hydrological and water quality model was established. The relationship between landscape index and pollutant concentration was explored by multiple linear regression and redundancy analysis. The results show that the concentration of total nitrogen in Ningjiang River Basin area in the west is relatively high, with a maximum value of 3. 91 mg/L. The total phosphorus concentration in Tingjiang River Basin area in the east is relatively high, with a maximum value of 2. 15 mg/L. The overall water quality of the basin is deteriorating. Landscape indicators can explain 81. 7% of the changes of non-point source pollution, and the larger the landscape area, the greater influence of its composition pattern on water quality than the spatial pattern. The percentage of woodland area is negatively correlated with non-point source pollution, while the landscape of farmland, town and grassland is opposite. Patch density, shape index and other spatial pattern indices of human landscape such as urban or farmland are negatively correlated with pollutant concentration. Dryland contributes more to non-point source pollution than paddy field. Adopting management measures such as returning grass to forestry and adjusting agricultural structure in the study area can help cut down the total nitrogen load by 1. 82% and 4. 63% respectively, and reduce the total phosphorus load by 1. 16% and 7. 31% respectively.