EVALUATING SATURATED HYDRAULIC CONDUCTIVITY OF A SOIL IN LABORATORY INVESTIGATIONS - AN EMPIRICAL-MODEL

In this work, we investigated the change in the hydraulic conductivity of a sandy-loam soil as a function of SAR and electrolyte concentrati on of the percolating solutions. High sodium adsorption ratios and low electrolyte concentrations caused a progressive reduction in the perc olating rate, resulting in a non-linear relationship between effluent volume and time. In all these cases (nonsteady-state drainage) Darcy's Law, which characterizes steady or stationary flow processes, does no t apply. The relationships between effluent volume and time were then analyzed to find an empirical equation for predicting drainage from so il columns under saturated conditions. Characteristic parameters of th e proposed model are the saturated hydraulic conductivity at time t = 0 (K(sat)degrees) and a rate constant (a) that takes into account the progressive reduction in the initial hydraulic conductivity of the flo w process. Validation of the model was found by applying it to montmor illonite-sand systems.