| Abstract: | Laboratory equipment was developed to measure nonsteady water potential and water content profiles in soil columns, with a high resolution in time and space. Moisture content was monitored using TDR-miniprobes and water potential was measured with microtensiometers. Gradients were applied by controlling the water potential at the bottom of the soil column during adsorption and desorption with the aid of a ceramic plate. The described experimental setup was designed specifically to determine effects of hysteresis on the water content/water potential and water potential/hydraulic conductivity relationships in undisturbed soil samples. In addition, an algorithm to process the data and to calculate the above mentioned relationships is presented. The algorithm includes the smoothing of data with Bezier functions before the calculation of the moisture retention curves and the conductivity functions. Results obtained from an albic E-horizon of a silty Luvisol are presented exemplarily to demonstrate the applicability of the proposed method in studying hysteresis effects. |
