Combining a Single Hydraulic Conductivity Measurement with Particle Size Distribution Data for Estimating the Full Range Partially Saturated Hydraulic Conductivity Curve

We have developed an approach for predicting the soil hydraulic conductivity curve (HCC) of soil using soil particle-size distribution (PSD) data and one single measurement of the hydraulic conductivity in the wet range of the HCC. Unlike other models, our approach does not need a prior determination of the soil moisture characteristic curve. The development was motivated by the fact that PSD data are often available or can be inferred from soil maps and also that the hydraulic conductivity at low matric suction can be determined easily with field infiltrometer devices. The HCC prediction was good at low matric pressures, but the model performance diminished at high matric pressures. The RMSE ranged from 0.165 to 2.016, the average being 0.755 (log-transformed hydraulic conductivity [cm d(-1)]). We propose to improve the accuracy of prediction models in the dry range of the HCC in future studies.