密云水库上游河流硝态氮含量空间分布格局

Nitrate Nitrogen Concentrations in the Upstream of Miyun Reservoir: Spatial Distribution Pattern

为了揭示密云水库上游河流硝态氮含量的空间分布规律,探讨其主要的影响因素。笔者对密云水库上游河流进行了全流域的水样采集,调查和收集了有关人类活动的数据(如人口、土地利用、化肥施用量等),利用流动注射分析仪测定了河水硝态氮含量。结果表明:密云水库上游东部的潮河水系的硝态氮含量高于西部的白河水系;河流硝态氮含量的空间分布格局与人类活动密切相关,表现在途径畜禽养殖场、居民点和农田时往往升高,而经过水坝、峡谷、森林时又常常降低,其排列次序依次是:畜禽养殖场>居民点>农田>水坝>峡谷>森林。河流硝态氮含量与人口密度、耕地比例和化肥氮施用量呈线性正相关关系。

To reveal the spatial distribution laws of nitrate nitrogen(NO3--N) concentration in the upstream of Miyun reservoir and its main influencing factors,we collected water samples throughout the whole watershed in the upstream of Miyun reservoir,and investigated the data on human activities such as population,land use types and fertilizer application,determined the concentration of NO3--N by a flow injection analyzer.The results showed that:the concentration of NO3--N in Chaohe River in the eastern upstream of Miyun reservoir was higher than that in the Baihe River in the western upstream;the spatial distribution pattern of NO3--N concentration was closely related with human activities;the concentration of NO3--N tended to rise in the way of livestock farms,settlements and farmland,while it tended to decrease in the way of dams,canyons and forests;so,the rank of NO3--N concentration in the stream passing through different land uses was:livestock farm> settlements>farmland>dams>canyons>forests.The concentration of NO3--N was positively correlated with population density,proportion of cultivated land,and fertilizer nitrogen application.