Recent models of the unsaturated hydraulic conductivity curve (UHCC) are the sum of separate UHCCs for domains of capillary water, film water, and water vapor. This requires parallel, noninteracting domains. A theoretical framework for aggregating domain conductivities to a bulk soil UHCC is presented to identify and possibly relax implicit assumptions about domain configuration. The paper develops arithmetic, harmonic, and geometric averages of the liquid‐water conductivities that can be arithmetically averaged with the vapor conductivity. However, current models for capillary and film conductivities are intrinsic, that is, valid within their respective domain. The vapor conductivity is a bulk conductivity, that is, it gives the conductivity of the gaseous domain as it manifests itself in the soil. Conversion relationships use the domain volume fractions as approximations of the as‐yet unknown weighting factors to convert between intrinsic and bulk conductivities. This facilitates consistent averaging of domain conductivities. Even with consistent averaging, a truly physically accurate model of the UHCC based on domain conductivities is fundamentally elusive. Nevertheless, models based on the three averages and the unweighted sum of the domain conductivities produce good fits to data for two soils but diverge in the dry range. The fitted curves for the capillary and film water depend on the averaging (or adding) method. Hence, they are not strictly characteristic of their respective domains. The true intrinsic domain conductivity functions may be impossible to determine.

中文翻译：

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平均或相加域电导率来计算非饱和土导水率

最近的不饱和水力传导率曲线 (UHCC) 模型是毛细管水、薄膜水和水蒸气域的单独 UHCC 的总和。这需要并行、非交互的域。提出了一种将域电导率聚合到大块土壤 UHCC 的理论框架，以识别并可能放宽有关域配置的隐含假设。该论文开发了液态水电导率的算术平均值、调和平均值和几何平均值，这些平均值可以与蒸汽电导率进行算术平均。然而，当前的毛细管和薄膜电导率模型是固有的，即在各自的领域内有效。蒸气电导率是体电导率，也就是说，它给出了气体域在土壤中表现出来的电导率。转换关系使用域体积分数作为尚未可知的权重因子的近似值，以在固有电导率和体积电导率之间进行转换。这有利于域电导率的一致平均。即使采用一致的平均值，基于域电导率的真正物理精确的 UHCC 模型基本上也是难以捉摸的。然而，基于三个平均值和域电导率未加权总和的模型与两种土壤的数据产生了良好的拟合，但在干燥范围内出现了偏差。毛细管水和薄膜水的拟合曲线取决于平均（或相加）方法。因此，它们并不是各自领域的严格特征。真正的本征域电导率函数可能无法确定。