Comparison of the single‐ring pressure infiltrometer and SATURO methods for determination of field‐saturated soil hydraulic conductivity

Abstract

Both the classical pressure infiltrometer (PI) method and the recently introduced SATURO device can be used to determine field-saturated soil hydraulic conductivity (Kfs) through a single-ring, steady-state experiment with two pressure heads. The introduction of this automated device raised questions about the validity criteria for infiltration data, its performance compared to the classical method, and the impact of a quick literature estimate of the α* (sorptive number) parameter on Kfs calculations. For two sandy-loam soils and a clay soil, the SATURO criterion, denoted as Criterion 1, differed from the classical, more stringent Criterion 2 in terms of valid measurements (success rates of 47%–100% vs. 13%–87%, respectively) but not greatly in summary statistics (KfsTPD [where TPD represents two-ponding-depth] means equal to 65–527 mm h⁻¹ in the former case and 70–300 mm h⁻¹ in the latter one). The PI and SATURO yielded similar mean KfsE (E stands for experimental) values (81–345 vs. 78–192 mm h⁻¹, respectively), but SATURO tended to give relatively smaller individual values. Using the first approximation value of α* instead of the experimental value led to differences in Kfs by 1.5 times at most, depending on the site. The classical data validity criterion should be applied to exclude physically impossible results. In practical use, both methods with similar run durations and water volumes yield comparable Kfs values. The first approximation value of α* could replace the experimental value in several cases. SATURO is a promising alternative to the PI for determining field-saturated soil hydraulic conductivity via single-ring, steady-state infiltration. There is room for improving its performance and also for simplifying its application in the field.