【摘要】 通过在河北省遵化地区于桥水库的上游选取景观特征差异明显的 4个典型流域 ,对地表水体采样分析 ,研究了非点源污染 N(水溶性 N)含量的季节动态变化特征以及与流域形状、景观空间分布格局的相互关系。结果表明 :1平水 (偏干 ,下同 )年份不同季节地表水中非点源污染 N含量高于干旱年份 ,反映出平水年份地表和地下径流对非点源污染的形成起到了较大作用。2干旱年份地表水中非点源污染 N含量季节变化比较平稳 ,且空间变异较小。而平水年份地表水体中非点源污染 N含量季节变化较大 ,表现出两种不同变化形式。 3流域形状和景观类型的相对重要性与非点源污染 N之间没有明显的相关关系 ,而“源”“汇”景观类型的空间分布格局在非点源污染的形成中起着重要作用更多还原

【Abstract】 With point-source pollution controlled effectively, nonpoint-source pollution, especially that resulting from agricultural land, has become the main factor affecting surface water quality. Much attention has been paid to the impact of fertilizer and pesticide application, wastewater irrigation, and land management on pollutant transport. However, landscape pattern also plays an important role in pollutant transport and detention. Landscapes may be classified into two types: “source” and “sink” landscapes, based on their functions in pollutant transport and detention. As a major contributor to eutrophication of waterbodies, nitrogen loss with run-off has received particular attention in studing on nonpoint-source pollution. In this study, four watersheds in the upper parts of the Yuqiao Reservoir Basin, Zunhua, Hebei Province, China, were chosen in order to study the relationship between landscape pattern and nitrogen-concentration dynamics. The results indicated that (1) nitrogen concentration in surface water within different seasons is higher in the rainfall-normal year than in the rainfall-deficit year and (2) the seasonal variation of nitrogen concentration in the rainfall-deficit year is smaller than in the rainfall-normal year. In the rainfall-normal year two types of seasonal variation in nitrogen concentration were found. The first type occurs when nitrogen concentration is lowest in the dry season, and rises rapidly from the dry season to the rainy season and then declines quickly from the rainy season to the mean-flow season. This mainly occurs in those areas where most “source” landscapes are close to the monitored waterbody. The second type of variation occurs when nitrogen concentration is low in the dry season, increases rapidly in the rainy season but does not reach its peak value until the mean-flow season. The second type of variation occurs in those areas where “source” landscape types are spread over the whole watershed. There is no clear relationship between watershed shape, relative importance of landscape types, and nitrogen concentration; however, the spatial distribution of “source” and “sink” landscape types in the watershed has a strong impact on the nitrogen concentration in surface water.更多还原