Chloride Displacement by Water in Homogeneous Columns of Three Soils1
- B. S. Ghuman and
- S. S. Prihar2
The comparative effects of soil texture on solute profiles during miscible displacement of noninteracting electrolytes are not available in the literature. We studied the displacement of a surface slug of chloride during infiltration and redistribution of water in columns of loamy sand, sandy loam, and silt loam soils.
For air-dry soil, maximum solute concentration occurred at the wetting fronts in sandy loam and silt loam but lagged behind the front in the loamy sand. Nevertheless, the position of the solute front coincided with the wetting front in all three soils. After redistribution, the salt peak for ν = 1.0 cm hour−1 was located several centimeters behind the wetting front in the air-dry loamy sand, but coincided with the wetting front in air-dry sandy loam and silt loam. In initially moist soils the salt peak lagged behind the wetting front in all soils. While the depth of chloride peak was not affected by initial soil wetness (θ1) in sandy loam and silt loam, in the loamy sand the salt peak occurred at shallower depth with θ1 = 0.10 than with θ1 = 0.07 cm3 cm−3.
An analytical solution of the solute transport equation described reasonably well the shape and location of chloride slug immediately after its displacement with a given rate and amount of water.
When infiltration and redistribution times were matched, water applied at ν = 1.0 cm hour−1 (or ponding in silt loam) moved the salt deeper than ν = 0.1 cm hour−1 in sandy loam and silt loam soils. But in the loamy sand the reverse was true because the redistribution water after the faster application moved through larger pores without taking along the salt.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .