Selecting the most suitable pedotransfer functions for estimating saturated hydraulic conductivity according to the available soil inputs

Abstract

Direct measurements of saturated hydraulic conductivity (Ksat) are costly and time-consuming. Alternatively, pedotransfer functions (PTFs) have been developed to estimate Ksat in terms of readily available soil properties. The goal of this study is to evaluate forty-five PTFs of Ksat. The functions were divided into four groups according to their input requirements: EP-Ksat group (F1.1-F1.9) require the effective porosity as inputs; SSC-Ksat group (F2.1-F2.12) require (sand, silt, clay contents); SSCBD-Ksat group (F3.1-F3.8) require (sand, silt, clay contents), bulk density; and SSCBDOM-Ksat group (F4.1-F4.16) require (sand, silt, clay contents), bulk density, and organic matter content. The results showed that the best PTFs were F1.9 and F1.5 in EP-Ksat group. For the SSC-Ksat group, the PTFs F2.1, F2.11. For the SSCBD-Ksat group, the PTFs F3.5, F3.6. For SSCBDOM-Ksat group, the PTFs F4.13 and F4.8. Results of this study are helpful for predicting Ksat inputs required for large scale hydrologic models with reliability.

Keywords

• Pedotransfer functions
• Saturated hydraulic conductivity
• Input requirements
• Effective porosity
• Particle size distribution