Accuracy of sample dimension-dependent pedotransfer functions in estimation of soil saturated hydraulic conductivity

Saturated hydraulic conductivity Ksat is a fundamental characteristic in modeling flow and contaminant transport in soils and sediments. Therefore, many models have been developed to estimate Ksat from easily measureable parameters, such as textural properties, bulk density, etc. However, Ksat is not only affected by textural and structural characteristics, but also by sample dimensions e.g., internal diameter and height. Using the UNSODA database and the contrast pattern aided regression (CPXR) method, we recently developed sample dimension-dependent pedotransfer functions to estimate Ksat from textural data, bulk density, and sample dimensions. The main objectives of this technical note were evaluating the proposed pedotransfer functions using a substantially larger database, and comparing them with seven other models. For this purpose, we selected more than nineteen thousand soil samples from all around the United States. Results showed that the sample dimension-dependent pedotransfer functions estimated Ksat more accurately, within 1.5 orders of magnitude boundaries of the measurements, than seven other models frequently used in the literature.