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Soil‐Water Movement in Response to Imposed Temperature Gradients
Author(s) -
Cassel D. K.,
Nielsen D. R.,
Biggar J. W.
Publication year - 1969
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/sssaj1969.03615995003300040007x
Subject(s) - loam , soil water , isothermal process , thermal diffusivity , water content , soil science , water column , environmental science , flux (metallurgy) , hydrology (agriculture) , materials science , geology , thermodynamics , geotechnical engineering , oceanography , physics , metallurgy
Redistribution of soil water within insulated, uniformly packed, horizontal samples of unsaturated Columbia fine sandy loam at several soil‐water contents was studied in response to imposed temperature gradients ranging from 0.5 to 1.0C/cm. Soil bulk density and initial, transient, and final soil‐water‐content distributions were determined each 0.5‐cm along the column by gamma‐radiation attenuation. Initial, transient, and final soil temperature distributions were monitored by glass‐encased thermistors at 2‐cm intervals—both at the center and 0.3 cm from the column wall. Apparent thermal and isothermal soil‐water diffusivity values were calculated using transient water content data. The observed net water flux was found to increase with decreasing water content throughout the 0.077–0.274 cm 3 /cm 3 range. For Columbia soil at 0.077 cm 3 /cm 3 the observed mean net water flux across 1‐cm sections of the soil showed acceptable agreement with that predicted by the theory of Philip and deVries; Fick's law and the modified Taylor‐Cary irreversible thermodynamic equation both underpredicted the observed fluxes.