22 December 2016 Soil water repellency characteristic curve influenced by drying and wetting processes
Yi Li, Xiaofang Wang, Zhenkai Cao, Bingcheng Si
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Until now, how wetting processes (WPs) and drying processes (DPs) affect the water drop penetration time (WDPT)–soil water content θ (or – water suction ψ) relationship, termed the soil water repellency characteristic curve (SWRCC), has remained unclear. WDPT vs. θ and water retention curves were measured and deduced for four wettable and hydrophobized soils during WPs and DPs. The performances of Gaussian model (GM), Lorentzian model (LRM), and Lognormal model (LGM) were compared for 32 measured SWRCC curves. The RWDPT, which is the ratio of the maximum WDPT during WPs to the WDPT of similar θ values during DPs, varied between 1.29 and 2.35 for wettable soils and between 1.3 and 138.1 for water-repellent soils, showing that hysteresis effects are important for SWRCC curves during DPs and WPs. Each model’s parameter was physically determined using the measured data. The Gaussian model was ultimately selected to represent the universal SWRCC relationship because of its features and general good performances not only for the unimodal SWRCC curves in both DPs and WPs in this study but also as reported in previously published data. The SWRCC can be roughly determined using two observed WDPT–θ (or water suction) data-points.

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Yi Li, Xiaofang Wang, Zhenkai Cao, and Bingcheng Si "Soil water repellency characteristic curve influenced by drying and wetting processes," Canadian Journal of Soil Science 97(2), 226-240, (22 December 2016). https://doi.org/10.1139/cjss-2016-0003
Received: 6 January 2016; Accepted: 1 December 2016; Published: 22 December 2016

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humectation et dessiccation
hydrophobicité du sol
soil moisture
soil water repellency
teneur en eau du sol
wetting and drying processes
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