中文摘要：

土壤优先流对包气带水流和污染物运移的影响已引起广泛关注,但大多数研究还停留在定性描述上,缺乏对优先流定量评价的标准。基于室内土柱实验获取的穿透曲线,分析了饱和条件下土壤溶质优先运移的一般规律,采用解析法模拟软件CX-TFIT拟合了溶质优先运移的参数,同时结合时间矩方法计算了定量评价优先流的指标PFSP。研究结果表明：时间矩方法中的一阶标准矩μ′1、二阶中间矩μ2以及偏态系数S可以定量刻画穿透曲线的特征,从而指示优先流的程度;PFSP能很好地刻画优先流作用的大小。该研究对优先流的定量评价具有重要指导意义。

英文摘要：

Because of its critical effect on field-scale soil water flow and transport of contaminants in soils, more and more research concerns are concentrated on preferential flow. However, few reports are found on quantitative evaluation of preferential flow though there are many reports in literature on qualitative descriptions of preferential flow. This paper presents the analysis of the characteristics of preferential transport based on the breakthrough curves obtained from soil columns in the lab and the evaluation of its extent based on the time moment analysis and two-region models by CXTFIT. A conclusion is made that thebreakthrough curves （BTCs） exhibit different shapes including some with early breakthrough and increased tailing curves. This qualitatively indicates the presence of preferential flow and different extent of preferential flow in the different soil columns. By time moment analysis, the first normalized moment （μ′1）, the second central moment（μ2）, and the skewness （S） were used as reference indices to denote the extent of preferential flow. Using transport parameters determined by the program CXTFIT and the timemoments of BTCs, an integrated parameter, PFSP, was calculated to ascertain or compare the extent of preferential flow. The calculation results indicate the value of PFSP could be used to quantify the extent of preferential flow when the breakthrough curves could be obtained. The conclusions in the study offer instructive implications in evaluation of preferential flow in the field.