汾河水库周边土壤氮流失风险评价

Risk Assessment of Soil Nitrogen Loss Around Fenhe Reservoir

[目的]对汾河水库周边土壤氮流失风险进行评价,为汾河水库周边的环境管理与污染控制提供依据。[方法]在对汾河水库周边土壤采样、全氮含量测定的基础上,结合研究区地形、降雨、土地利用类型、径流、化肥施用、人口、潜在污染源距离等因子,采用通用水土流失方程和氮指数评价法进行评价。[结果]从研究区整体来看,土壤氮流失风险水平并不高,风险评价等级为低、中、高、极高程度的面积分别占研究区总面积的78.04%,2.72%,9.31%和9.93%;从空间上来看,氮流失风险较高的区域主要集中分布在研究区的西南和东北部,土地利用类型主要是地势平坦的耕地。中等流失风险程度的区域大部分位于沿河山地地区,土地利用类型为林地、草地及耕地。低风险程度的区域主要位于河谷地区较为平坦的地区,土地利用类型以草地和耕地为主。[结论]采用的氮指数评价法综合考虑了土壤氮流失的源因子和迁移因子,可以科学有效地反映研究区土壤氮流失风险的水平及空间分布。

[Objective]The objective of this paper is to evaluate risk of the soil nitrogen loss around the Fenhe Reservoir in order to provide scientific support for the environmental management and pollution control in Fenhe River watershed.[Methods]Soil samples around the Fenhe Reservoir were collected in 2011,and soil total nitrogen contents were determined.Using the factors such as topography,climate,land use type,fertilizer use,population and distance to potential pollution source,we used the nitrogen index evaluation method and revised universal soil loss equation（RUSLE）to evaluate the risk of soil nitrogen loss in the study area.[Results]The risk of soil nitrogen loss is low in the study area.The proportion of low,medium,high and higher risk level is 78.04%,2.72%,9.31% and 9.93%,respectively.The areas with high risk of nitrogen loss are mainly located in the southwest and northeast of the research area,and the land use type is mainly farmland.The medium risk areas are mostly located in mountainous area along the river and the land use types are forest,grassland and farmland.The low risk areas are mainly located in the river valley area and the land use types are grassland and farmland.[Conclusion]Nitrogen index assessment is an effective method to assess the nitrogen loss risk.Using the source and migration factor of soil nitrogen loss together,this study can provided scientific support for environmental management and pollution control for Fenhe Reservoir.