Comparing two methods to perform a beerkan infiltration run in a loam soil at different dates

Abstract

Performing beerkan infiltration runs with different heights of water pouring could help to obtain saturated soil sorptivity, S, and hydraulic conductivity, Ks, data usable to explain and simulate hydrological processes. However, most of the available information on the L (low height of water pouring, nearly 3 cm) - H (high height, 1-2 m) methodology refers to runs making use of a relatively limited number of water volumes and there is some sign that a few water volumes could yield an incomplete description of soil alteration phenomena induced by wetting. For a loam soil, the objective of this investigation was to determine water pouring height effects on the S and Ks values obtained in different sampling dates with more than usual amounts of applied water. Soil alteration due to the mechanical impact of the applied water appeared almost completed by the end of the runs in all cases but in a more advanced stage when the soil was initially more sorptive and conductive. Overall, the H runs yielded 2.3-2.8 times smaller S values and 8.5-14.5 times smaller Ks values than the L runs but differences between the L and H methodologies varied during the sampling period. In particular, these differences were smallest when the soil was initially relatively wet and little sorptive and conductive (S and Ks values differing with the experiment by no more than two times) and largest in the opposite conditions (S and Ks values differing by 3 and 17-21 times, respectively). The L runs yielded coefficients of variations, CV, of 14-60% for S and 45-171% for Ks, depending on the sampling date, and a ratio between the highest and the lowest mean of 2.5 for S and 11.8 for Ks. With the H runs, the corresponding CV values were 14-38% for S and 35-107% for Ks and two means differed at the most by 1.3 times for S and 2.2 times for Ks. Therefore, the H runs described a soil that was less sorptive, less conductive, more spatially homogeneous and more temporally stable than the L runs. Less runs could be enough to parameterize the soil in a disturbed condition as compared with the undisturbed one. Further testing the L-H methodology in other environmental conditions is recommended in the perspective to develop simple field methods to determine the hydrodynamic properties of both a nearly undisturbed soil and an intensively disturbed soil.