identifier |
http://anzsoil.org/def/au/asls/soil-profile/Water-repellence |
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definition |
Water repellence of some soils, usually sandy, is caused by a series of long-chain
polymethylene waxes, made up of acids, alcohols and esters, attached to the sand grains
(Ma’shum et al. 1988). These soils occur Australia-wide but are more widespread in
southern Australia (Wetherby 1984, McGhie and Posner 1980). Degree of repellence is
assessed by determining the concentration of ethanol required to wet the sand in 10
seconds (King 1981). An abbreviated form of this method is recommended for routine
field situations.
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note |
Soil temperature at testing should be between 15ºC and 25ºC. Higher temperatures will
increase, and lower decrease, rates of absorption. Industrial-grade methylated spirits,
available from chemists, at a concentration of 23.9 ml per 200 ml water can be substituted
for the 2-molar ethanol to obtain approximate values.
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