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The effect of temperature‐induced soil water repellency on transient capillary pressure–water content relations during capillary rise
Author(s) -
Reszkowska A.,
Bachmann J.,
Lamparter A.,
Diamantopoulos E.,
Durner W.
Publication year - 2014
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12139
Subject(s) - capillary action , saturation (graph theory) , soil water , chemistry , water content , subsoil , capillary pressure , tensiometer (surface tension) , water table , wetting , soil science , surface tension , environmental science , geotechnical engineering , materials science , thermodynamics , composite material , porous medium , geology , groundwater , porosity , mathematics , organic chemistry , combinatorics , physics
Summary Long‐term capillary rise experiments (0 to about 89 000 hour) were performed at 19°C on homogenized and heat‐treated podsolic forest top‐ and subsoil samples. These were packed into columns, the bases of which were then partially immersed, at constant depth, in water reservoirs to simulate a constant water table. Selected columns were equipped with tensiometer and TDR probes. Other columns were removed at prescribed times and divided into 2‐cm horizontal segments whose volumetric water contents were determined. The degree of saturation was then estimated by comparison with the capillary rise in duplicate arrangements of samples immersed in ethanol. It was found that the heat treatments conferred increased water repellency ( WR ) on the soil, which increased with temperature (significantly so at greater than 60°C). This had a profound effect on the capillary rise characteristics and development of water content in the soil behind the wetting front, indicating an effective, albeit slow, reduction in effective WR . This has implications for hydraulic modelling of soils with significant WR and demonstrates that sub‐surface WR exerts a significant influence on capillary rise from a water table and suggests that commonly used indicators of surface WR using droplet tests may not be useful for such modelling purposes.