Different scenarios for inverse estimation of soil hydraulic parameters from double-ring infiltrometer data using HYDRUS-2D/3D
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Department of Soil Science, College of Agriculture, Shahrekord University, Shahrekord 88186-34141, Iran
Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
Department of Soil Science, College of Agriculture, Vali-e-Asr University, Rafsanjan, Iran
Department of Computer Engineering, Faculty of Engineering, Vali-e-Asr University, Rafsanjan, Iran
Publish date: 2016-04-28
Int. Agrophys. 2016, 30(2): 203–210
In this study, HYDRUS-2D/3D was used to simulate ponded infiltration through double-ring infiltrometers into a hypothetical loamy soil profile. Twelve scenarios of inverse modelling (divided into three groups) were considered for estimation of Mualem-van Genuchten hydraulic parameters. In the first group, simulation was carried out solely using cumulative infiltration data. In the second group, cumulative infiltration data plus water content at h = −330 cm (field capacity) were used as inputs. In the third group, cumulative infiltration data plus water contents at h = −330 cm (field capacity) and h = −15 000 cm (permanent wilting point) were used simultaneously as predictors. The results showed that numerical inverse modelling of the double-ring infiltrometer data provided a reliable alternative method for determining soil hydraulic parameters. The results also indicated that by reducing the number of hydraulic parameters involved in the optimization process, the simulation error is reduced. The best one in infiltration simulation which parameters α, n, and Ks were optimized using the infiltration data and field capacity as inputs. Including field capacity as additional data was important for better optimization/definition of soil hydraulic functions, but using field capacity and permanent wilting point simultaneously as additional data increased the simulation error.