农村小流域景观结构与水质耦合关系分析——以仪征市陈集镇为例

选择江苏省仪征市陈集镇2个典型的农村小流域进行水质监测和景观空间分异耦合关系研究,结果表明:不同地势区景观结构差异明显,水环境特征也有较大差别。随着地势的降低,总氮、总磷浓度在小徐庄流域呈降低趋势,而高塘流域则先升高后降低;总磷、总氮、氨氮、硝态氮浓度与源景观比例、沟渠密度和景观多样性指数具有良好的相关关系,逐步回归分析发现,94%的总氮浓度由源景观比例和沟渠密度决定,80%以上的氨氮和硝态氮浓度由源景观比例决定。因此,可以通过对流域景观结构的优化调整,达到对流域景观中养分的有效管理,实现对农业非点源污染的控制。

Relationship Between Landscape Stucture and Water Environment in Small Rural Watersheds

Two typical small rural watersheds in Chenji Town of Yizheng were selected in a study of coupling relationships between water quality and landscape stucture. Results show that (1) landscape structure varied sharply with terrains, and so did characters of the water environment. With declining terrain, concentrations of TN and TP decreased in Xiaoxuzhuang watershed, but rose first and then fell in Gaotang watershed;(2) good correlations were observed of concentrations of TP, TN, NH_3-N, and NO_3~--N with proportion of source landscape, ditch density, landscape diversity index;and (3) stepwise regression revealed that 94% of TN depended on proportion of source landscape and ditch density, while over 80% of NH_3-N and NO_3~--N on proportion of source landscape. It is advisable to run effective management of nutrients in the watershed landscape and reinforce control of agricultural non-point source pollution by optimizing landscape structure of the watersheds.