SALT DISPERSION COEFFICIENTS NEAR AN EVAPORATING SURFACE

Columns instrumented with tensiometers and Richards' salinity sensors were used with coarse- and fine-textured soils. Water was supplied to a water table at the base of the columns and approximately steady state evaporation from the soil surface was established. Dispersion coefficients were calculated from salt gradients and evaporation rates in regions of the soil where suctions ranged from 0. 1 to several bars. Dispersion increased with increased solution flux and average solution velocity.