Estimating saturated hydraulic conductivity of soil samples from Kansas mesonet database

Abstract In soil physics, saturated hydraulic conductivity, , is a key soil hydraulic parameter governing the movement of water and solutes, with broad implications for transport processes under variably saturated conditions. Its accurate estimation, however, is challenging and requires precise characterization of pore space. In this study, we applied concepts of critical path analysis (CPA) to estimate from soil water retention curve. To evaluate the CPA, we used observations made on 313 undisturbed soil cores from the Kansas Mesonet soil physical property database in which the value of spans over five orders of magnitude in variation. We found that the CPA estimated reasonably well with root mean square log‐transformed error RMSLE = 0.87. For most samples, the predicted values were around the 1:1 line within a factor of 10 of the measurements. We also estimated using five other methods, but none was more accurate than the CPA. We found the RMSLE values were 1.42 for the Kozeny–Carman model, 1.28 for the Revil, Glover, Pezard, and Zamora model, 1.18 for the Johnson, Koplik, and Schwartz model, 2.68 for the Mishra and Parker model, and 1.40 for the Guarracino model. This study provides one of the first large‐sample, field‐based validations of the CPA framework for estimating in predominantly fine‐textured soils.