Soil Temperature and Water Content Changes During Drying as Influenced by Cracks: A Laboratory Experiment
1970
Selim, H. M. | Kirkham, Don
A container consisting of three identical compartments each 30 cm long, 30 cm deep, and 10 cm wide, was used to study the influence of artificial soil shrinkage cracks on heat and water content redistribution in three soil materials subjected to wind or radiative drying of 1.18 and 2.54 cm of water per 24 hours evaporation potential, respectively. Three crack widths were used, 0, 0.64, and 1.91 cm. Moisture content and temperature distributions were measured with time up to 12 days. The cracks decreased water content as much as 5 to 10% by volume. Evaporation through crack walls caused lateral movement of water for a distance of 4 to 5 cm from the wall of a 0.64-cm crack after 12 days of radiative drying. These distances were greater up to 14 cm (for the sand). Under wind, distances of lateral movement of water were about 5 cm, for all drying times. For all three soils with cracks, after 4 days of wind drying, soil temperature was cooler (1 to 2C lower) than for the soils with no cracks. Under radiation all three soils were warmer (5 to 10C higher) than soils with no cracks, after 4 days. In general, shrinkage cracks increased evaporation from bare soil 12–16% with cracks 0.64 cm wide and about 30% with cracks 1.91 cm wide as compared to evaporation from soils with no cracks.
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