Scaling Relationships between Saturated Hydraulic Conductivity and Soil Physical Properties

Saturated hydraulic conductivity ( K s ) is an important soil hydraulic property that affects water flow and the transport of dissolved solutes. Obtaining sufficient and reliable K s data for large‐scale process modeling is always a challenge due to the extremely high spatial variability. The objectives of this study were (i) to determine if a monofractal or multifractal approach is needed to describe the variability in K s and its soil surrogates, and (ii) to identify which soil property best reflects the spatial distribution of K s across a wider range of scales. Saturated hydraulic conductivity and soil physical property data were collected from a 384‐m transect, located at Smeaton, SK, Canada. Observation scale variability and relationships were examined using statistical and geostatistical methods. Statistical scale‐invariance was evaluated through the Hurst scaling parameter ( H ). Multiple scale variability and relationships were studied using multifractal and joint multifractal techniques. Results indicate that for all the studied variables 0.80 < H < 0.90, suggesting a certain degree of statistical scale‐invariance and long‐range dependency. At the observation scale, the variability in K s was significantly related to sand (SA) and silt (SI) distribution ( R = 0.40 for SA and −0.39 for SI, P < 0.01; n = 128), whereas, across a wider range of scales, the variability in K s was related only to clay (CL) and organic C (OC). The result indicates scale dependent relationships between K s and soil physical properties, which implies that the success of predictive models such as pedotransfer functions (PTFs) and K s aggregation techniques depends largely on the correspondence between observation and implementation scales.