Estimation and analysis of soil hydraulic properties using Beerkan infiltration experiment

Studying of water and contaminants transport in the vadose zone required determination of soil hydraulic properties. The current study aimed to estimate and analysis the soil hydraulic parameters through inexpensive experiment of Beerkan in six sample points of various soil textural classes، in Asalem region، in Guilan (Iran). Shape and scale parameters of the hydraulic characteristic curves were estimated from particle size distribution analysis and infiltration experiment respectively. Four fitting methods were used and copmaired including BEST-slope (B/s)، BEST-intercept (B/i)، Derivative Linearization (DL) and Cumulative Linearization (CL). Although scale parameters of any sample points were not estimated feasibly and accurately by DL and CL methods but B/s and B/i methods acted as complementary to each other and estimated feasible and accurate values for scale parameters of all six experimental points. The estimated values of sorptivity by B/s and B/i method were not significantly different، but saturated hydraulic conductivity values estimated by B/i was greater than B/s values. Also comparison of these two methods by relative error showed that B/s is more accurate than B/i. It seems that B/i method overestimates saturated hydraulic conductivity. It is recommended therefore to use B/s method for estimating soil hydraulic properties.