Abstract: In the study of water flow through soil, an important part is to choose correct diffusion scheme in calculating soil water capillary conductivity. It is critical in studying the property of soil water diffusivity by correctly using difference scheme of diffusivity coefficients in diffusion equations. In this paper, a set of new difference scheme of diffusivity coefficients has been developed to adapt to the calculation of soil water capillary conductivity in interior boundary between two neighbouring model layers. The results are satisfactory by controlled infiltration tests.

Key words: soil diffusivity coefficient, soil wetness, capillary function, soil interior boundary

摘要： 土壤水传导是一门十分重要的研究课题，土壤中水分在毛细作用下的扩散问题是研究土壤水传导的重要组成部分，而扩散系数离散方案在差分方程中的正确使用是研究水分在土壤中扩散特性的关键。本文推导出适用于计算土壤水分扩散特性 的一套新的扩散系数差分方案，并通过控制渗透试验检验取得很好的效果。

关键词: 土壤扩散系数, 土壤内边界, 土壤平均湿度, 土壤水分扩散毛细作用