Water repellency (WR) significantly affects the hydraulic behavior of soils. Although WR often is regarded as a phenomenon with implications for dry soils, it is prevalent at water contents (w) exceeding the wilting point water content. Because the measurement of the WR–w relationship is laborious, alternative more time-efficient methods are desirable to estimate parameters of the WR-w curve. Using 32 high organic carbon (OC) soils from Denmark and South Greenland, we characterized the water vapor sorption isotherms (WSIs), investigated the interrelated effects of OC and clay contents on WSIs and the WR–w relationship, and further evaluated if parameters of the WR-w curve may be derived directly from WSIs. The samples exhibited OC and clay contents ranging from 0.014 to 0.369 kg kg^–1 and from 0.02 to 0.16 kg kg^–1, respectively. The WSIs measured for relative humidity (RH) values between 3 and 93%, were strongly hysteretic, were OC dependent, and could be accurately characterized with the Guggenheim, Anderson, and de Boer model. Further, the WR_area and w_non parameters, derived from WR measured for several w, were well estimated with linear regressions based on OC content and multiple linear regressions based on OC and clay contents. Estimations for WR_area and w_non based on the WSI parameter w_m-a were superior to OC and clay content. Finally, we established mathematical expressions that estimate WR_area or w_non from any air-dry w obtained from either the desorption or adsorption isotherms between 10 and 90% RH.

中文翻译：

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将水蒸气吸附与有机碳含量高的土壤中的拒水性联系起来

防水性 (WR) 显着影响土壤的水力行为。虽然 WR 通常被认为是一种对干燥土壤有影响的现象，但它在含水量 ( w ) 超过枯萎点含水量时普遍存在。因为 WR- w关系的测量是费力的，所以需要其他更省时的方法来估计 WR- w曲线的参数。使用来自丹麦和南格陵兰的 32 种高有机碳 (OC) 土壤，我们表征了水蒸气吸附等温线 (WSI)，研究了 OC 和粘土含量对 WSI 和 WR- w关系的相关影响，并进一步评估了参数WR- w曲线可以直接从 WSI 导出。样品的 OC 和粘土含量分别为 0.014 至 0.369 kg kg ^–1和 0.02 至 0.16 kg kg ^–1。相对湿度 (RH) 值在 3% 到 93% 之间测量的 WSI 具有很强的滞后性，并且依赖于 OC，并且可以使用 Guggenheim、Anderson 和 de Boer 模型进行准确表征。此外，从几个w测量的 WR 导出的 WR_面积和w_非参数，可以用基于 OC 含量的线性回归和基于 OC 和粘土含量的多元线性回归很好地估计。基于 WSI 参数的WR_面积和w_非估计w _m-a优于 OC 和粘土含量。最后，我们建立了数学表达式，可以根据从10% 到 90% RH 之间的解吸或吸附等温线获得的任何风干w来估计 WR_面积或w _non。