Modelling Soil Wetting Patterns under Drip Irrigation Using Hydrus-3D and Comparison with Empirical Models

Ahmed A. M. Al-Ogaidi, Aimrun Wayayok, MD Rowshon Kamal and Ahmad Fikri Abdullah

ABSTRACT

Objective - The optimal design, operation, and management of drip irrigation systems relies highly on a suitable combination of emitter discharge, spacing between emitters and laterals, rooting depth, soil hydraulic properties, and wetting pattern dimensions under single emitter. The wetting pattern dimensions under surface emitter can be measured in field, laboratory or estimated by modelling. In this study, a comparison was conducted between some empirical models for estimating the wetting pattern dimensions and the well-known numerical model Hydrus-3D.

Methodology/Technique - Data from published papers covering wide range of soil textures, emitter discharges, application times, bulk densities, saturated hydraulic conductivities, and initial moisture contents were used. In order to assess the performance of the considered models, the estimated wetting pattern dimensions were compared with the observed ones statistically using some statistical criteria such as mean error, root mean square error, and model efficiency.

Findings - The results revealed that the performance of empirical models varied among the models depending on the data that used in deriving the model. Some empirical models showed high performance in predicting the wetting pattern dimensions even better than Hydrus-3D.

Novelty - Hydrus-3D is a numerical model which can simulate soil water movement in multi conditions unlike empirical models which are appropriate for limited conditions

Type of Paper: Review

Keywords: Emitter; Numerical Model; Wetted Depth; Wetted Radius; Wetted Soil Zone.

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