Retention curves of soil from the liz experimental catchment obtained by three methods

Abstract

Abstract:The retention curves were measured in the soil from the Liz experimental catchment (Šumava). The sand table and pressure extractor methods were used to obtain a 13-point retention curve for undisturbed soil samples taken from 6 depths. The data points of the individual retention curves were fitted in with the analytical expression of and the reference retention curves were calculated for each depth by scaling. For the same soil, the retention curves were estimated by the artificial neural network method by and the use of the empirical Pedotransfer function. The numerical experiment, which represented the infiltration and redistribution processes, was conducted using of all three sets of retention curves. simulated water storages and pressure fields obtained using two sets of estimated parameters produced similar results, however they did not approximate well the modelling results obtained with the use of the measured reference parameter set. Of the two sets of pedotransfer functions (PTFs), which have been tested in this study, the empirical PTF of showed a slightly better agreement with the measured retention curves. The results give a guideline for the application of the retention curves estimation by the pedotransfer function for the soil from the Liz catchment.

Year-round estimation of soil moisture content using temporally variable soil hydraulic parameters

“…The comparison of the obtained threshold values with soil water retention curves measured in the area (Snehota et al, ) shows the corresponding values of ϴ fc (suction pressure = −33.6 kPa), which is approximately 0.30 cm 3 cm −3 , with the TT model ϴ c . The wilting point (suction pressure = −150 kPa) equals 0.18 cm 3 cm −3 and is underestimated both by the TT model and the Laio model.…”

“…The only threshold value kept fixed was the saturation soil water content (ϴ s ). The average value for the entire soil column was determined to be 0.52 (Snehota, Dubovec, Dohnal, & Cislerova, ). The remaining five thresholds were optimised by means of calibration, as their derivation from the water retention curve can be associated with significant errors (due to air entrapment, hysteresis, etc.).…”

Macroscopic Modeling of Plant Water Uptake in a Forest Stand Involving Root‐Mediated Soil Water Redistribution

“…For the purpose of numerical modeling, the soil profile was divided into four layers distinguished by different soil hydraulic properties—the organic litter layer and three mineral soil layers (Table 1). The soil hydraulic parameters were evaluated using combined information on retention data (Snehota et al, 2009), measured by standard laboratory methods (sand tank and a pressure plate apparatus), and simultaneous long‐term monitoring of soil water pressures and water contents in situ. Saturated hydraulic conductivities were determined by means of ponded infiltration tests and tension disk infiltrometers.…”