中文摘要：

为全面了解对美国中部Illinois州具有浅层排水系统的轮作农业地区的面源污染问题,利用主成分分析方法及多元线性回归,对Little Vermillion River流域磷流失影响因素主成分进行分析.结果表明,磷流失的影响因素基本分为3大主成分：一是生物主成分,包括温度、植被类型、覆盖因子、生物量、散蒸量;二是水力主成分,降雨及流量;三是人为干扰主成分,施肥量及耕作内容.其中水力主成分对流失的影响最大,尤其是对浅层排水中磷流失的影响.

英文摘要：

In order to get a fully understanding of non-point pollution problem in rotation agricultural watershed at the central United States Illinois, USA, Principal component analysis （PCA）was used to do the water quality evaluation of the Little Vermilion River watershed. The PCA approach divided various factors that influence phosphorus transport into three principal components. The first component, botanical component, contained air temperature, cover phenotype, evapotranspiration, cover factor and dry mass factors. The second component contained precipitation and flow, which was defined as hydrologic component. The third component included tillage practices and nitrogen application, and was termed as anthropogenic component. The result showed that the hydrologic component impact phosphorus loss most than other components, especially for subsurface drainage water.