Comparing Beerkan infiltration tests with rainfall simulation experiments for hydraulic characterization of a sandy‐loam soil

Abstract

Saturated soil hydraulic conductivity, Ks, data collected by ponding infiltrometer methods and usual experimental procedures could be unusable for interpreting field hydrological processes and particularly rainfall infiltration. The Ks values determined by an infiltrometer experiment carried out by applying water at a relatively large distance from the soil surface could however be more appropriate to explain surface runoff generation phenomena during intense rainfall events. In this study, a link between rainfall simulation and ponding infiltrometer experiments was established for a sandy‐loam soil. The height of water pouring for the infiltrometer run was chosen, establishing a similarity between the gravitational potential energy of the applied water, Ep, and the rainfall kinetic energy, Ek. To test the soundness of this procedure, the soil was sampled with the Beerkan estimation of soil transfer parameters procedure of soil hydraulic characterization and two heights of water pouring (0.03 m, i.e., usual procedure, and 0.34 m, yielding Ep = Ek). Then, a comparison between experimental steady‐state infiltration rates, isR, measured with rainfall simulation experiments determining runoff production and Ks values for the two water pouring heights was carried out in order to discriminate between theoretically possible (isR ≥ Ks) and impossible (isR < Ks) situations. Physically possible Ks values were only obtained by applying water at a relatively large distance from the soil surface, because isR was equal to 20.0 mm h−1 and Ks values were 146.2–163.9 and 15.2–18.7 mm h−1 for a height of water pouring of 0.03 and 0.34 m, respectively. This result suggested the consistency between Beerkan runs with a high height of water pouring and rainfall simulator experiments. Soil compaction and mechanical aggregate breakdown were the most plausible physical mechanisms determining reduction of Ks with height. This study demonstrated that the height from which water is poured onto the soil surface is a key parameter in infiltrometer experiments and can be adapted to mimic the effect of high intensity rain on soil hydraulic properties.

Comparing Transient and Steady-State Analysis of Single-Ring Infiltrometer Data for an Abandoned Field Affected by Fire in Eastern Spain

“…All average K fs values were lower than the expected saturated conductivity on the basis of the soil textural characteristics alone, e.g., K s = 4.5 mm·h −1 for a silt loam soil according to Carsel and Parrish [68]. This suggested that soil macroporosity in the control and burnt site did not influence the results [28]. All differences between the average K fs values of different sites and sampling campaigns were not statistically significant according to the Tukey honestly significant difference test (p < 0.05).…”

“…The cores were used to determine the soil bulk density, ρ b (g·cm −3 ), and the initial volumetric soil water content, θ i (m 3 ·m −3 ). According to other investigations, the saturated soil water content, θ s (m 3 ·m −3 ), was approximated by total soil porosity, determined from bulk density ρ b (e.g., [28,37,[43][44][45][46][47][48]). Soil organic matter was determined by the Walkley-Black [49] method.…”

“…In general, establishing the reliability of new methods is not a simple task, also due to the high K fs variability both in space and time [23,24]. Moreover, many other sources of variability may also arise when comparing different field measurement techniques, such as sample size [25], ring diameter [26], source shape [27] and field sampling procedure [28,29]. One could expect that considering laboratory measurements as targeted values would help to check the reliability of field data.…”

Intercomparison of soil pore water extraction methods for stable isotope analysis and interpretation of hillslope runoff sources

“…In order to check whether soils were entirely saturated at the beginning of our experiment, the calculated soil porosity of 0.43 cm 3 /cm 3 was assumed to coincide with saturated soil water content ε (θs, ε = ε), as suggested by many authors (e.g., Di Prima, ; Minasny et al, ; Prima et al, ). This approach assumes a low to medium spatial variability for both θs and bulk density (Di Prima, ).…”

“…The soil porosity, ε (cm 3 /cm 3 ), was calculated from the bulk density data, assuming a soil particle density of 2.65 g/cm 3 (Minasny, McBratney, & Bristow, 1999;Prima et al, 2017).…”