In-tandem methodology and recommendations for measuring soil hydraulic properties from saturation to dryness in laboratory conditions

Abstract

Laboratory determination of soil water retentions and hydraulic conductivity curves requires different techniques, depending on the number of data points needed. An important consideration in technique selection is soil sampling, particularly the distinction between disturbed and undisturbed samples, as laboratory methods can differ significantly for each kind of soil sample. This work addressed the increasing interest within soil physics in using methodologies that cover a wide range of water content and suction to determine soil hydraulic properties accurately. Achieving soil samples representative of physical processes is challenging due to the time required for measurements and the combination of techniques necessary to characterize soil water retention and hydraulic conductivity curves. A detailed workflow in-tandem for soil hydraulic curve measurements is presented, comprising more than 4 500 measurements to describe both curves from saturation to dryness. To enhance reproducibility and reduce uncertainty in laboratory measurement, this work offers ten best practice recommendations focused on sample preparation, instrument handling, and data management. This work aims to contribute to improved methodologies in soil physics laboratories and promote standardized practices. This work also contributes to advancing the reliability and accuracy of soil hydraulic properties assessment, thereby supporting improved research and application in soil science.