Estimating field-saturated soil hydraulic conductivity by a simplified Beerkan infiltration experiment

Field-saturated soil hydraulic conductivity, Kfs, is highly variable. Therefore, interpreting and simulating hydrological processes, such as rainfall excess generation, need a large number of Kfs data even at the plot scale. Simple and reasonably rapid experiments should be carried out in the field. In this investigation, a simple infiltration experiment with a ring inserted shortly into the soil and the estimation of the so-called a* parameter allowed to obtain an approximate measurement of Kfs. The theoretical approach was tested with reference to 149 sampling points established on Burundian soils. The estimated Kfs with the value of first approximation of a* for most agricultural field soils (a* = 0.012mm_1) differed by a practically negligible maximum factor of two from the saturated conductivity obtained by the complete Beerkan Estimation of Soil Transfer parameters (BEST) procedure for soil hydraulic characterization. The measured infiltration curve contained the necessary information to obtain a site-specific prediction of a*. The empirically derived a* relationship gave similar results for Kfs (mean = 0.085mms_1; coefficient of variation (CV) = 71%) to those obtained with BEST (mean = 0.086mms_1; CV = 67%), and it was also successfully tested with reference to a few Sicilian sampling points, since it yielded a mean and a CV of Kfs (0.0094mms_1 and 102%, respectively) close to the values obtained with BEST (mean = 0.0092mms_1; CV = 113%). The developed method appears attractive due to the extreme simplicity of the experiment.