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Temperature Dependence of Soil Hydraulic Properties: Transient Measurements and Modeling
Author(s) -
Joshi Deep C.,
Iden Sascha C.,
Peters Andre,
Das Bhabani S.,
Durner Wolfgang
Publication year - 2019
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2019.04.0121
Subject(s) - loam , hydraulic conductivity , soil water , water retention , saturation (graph theory) , surface tension , soil science , isothermal process , materials science , thermodynamics , environmental science , mathematics , physics , combinatorics
The modeling of the water flow in soils under non‐isothermal conditions requires consideration of the temperature influence on the soil hydraulic properties (SHPs). The surface‐tension‐viscous‐flow (STVF) theory considers the influence of temperature on viscosity, density and surface tension and provides a conceptual framework for the temperature dependence of the water retention and hydraulic conductivity curves. Previous research has shown discrepancies between observed temperature effects on SHPs and the STVF theory. Furthermore, experimental investigations, which investigate the temperature effects on both the retention and conductivity curves in a combined manner, are still rare. To overcome this limitation, we measured the SHPs of three different soils at three different temperatures (5, 20, and 35°C) with the evaporation method, which yields highly resolved retention data in the suction range between saturation and 100 kPa, and conductivity data in the range of ∼6 to 100 kPa. The classic STVF‐based model and two alternative models were tested. Results showed that the temperature dependence of SHP was larger than predicted by the STVF theory and depends on the soil. The effect was strongest for the silt loam, followed by the sand and smallest for the sandy loam. Fits of the Grant and Stoffregen models to the experimental data were excellent, but required soil‐specific parameters. This indicates that the surface properties of the soil matrix might contribute to the effects of temperature on SHPs.