于桥水库流域农业非点源磷污染控制区划研究

以于桥水库流域28个次级小流域作为区划对象，以影响该区域农业非点源磷污染的6个主要因子，包括降雨侵蚀力因子(R)，土壤可蚀性因子(K)，地形因子(LS)，植被覆盖因子(C)以及土壤有效磷含量(SAP)和化肥磷施用量(FP)，作为区划因子，采用系统聚类法进行区划，将于桥水库流域分为4类磷污染控制类型区，分析了各个类型区的生态环境特征、农业非点源磷污染特征和主要影响因子，提出相应的控制措施。为进一步进行更深入的研究提供科学依据。

Pollution-controlling Regionalization of Agricultural non-point Phosphorous in Yuqiao Reservoir Watershed

Yuqiao Reservoir Watershed is divided into four pollution-controlling regions of phosphorous loss by using clustering method, taking 28 sub-watersheds as regionalization objects. Six impacting factors of agricultural non-point source phosphorous pollution were regarded as regionalization factors, including 4 factors of Universal Soil Loss Equation (USLE): rainfall-runoff factor (R), soil erodibility factor (K), landform factor (LS), vegetation factor (C) as well as soil available phosphorus (SAP) and fertilizer phosphorus application rate (FP). It was found that the important regionalization factors greatly effecting the regionalization results of agricultural non-point phosphorous were rainfall-runoff factor (R), landform factor (LS), vegetation factor (C) and fertilizer phosphorus application rate (FP), which had great variability among four pollution-controlling regions. While soil erodibility factor (K) and soil available phosphorus (SAP) had little importance for the regionalization because of their small variability among different regions. The natural eco-environmental characteristics, phosphorous pollution characteristics and its major impacting factors in each region were analyzed, and based on that, the pertinent control measures were proposed, providing scientific foundation for carrying out the in-depth study in the following work.