Document Type : Research Article
Authors
1 Department of Irrigation and Drainage, Faculty of Agriculture, Tarbiat Modares University
2 Agriculture and Engineering, Reasearch Institute, AERI, Karaj
Abstract
Abstract
This study addresses two dimensional infiltration from irrigated furrows. The basic approach is to develop a two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The edge effect is the difference between the cumulative infiltration per unit of adjusted wetting perimeter and the corresponding one-dimensional infiltration. This approach was evaluated using field measured furrow experiments and double ring infiltration tests. In this study, two series of experiments was conducted in 2010 on a clay loam soil. The first series of the tests included five experiments with inflow rate (0.3-0.8 ls-1) on free draining furrows having 110 meters in length, 75 cm wide and general slope of 0.008 m m-1. The second series of the experiments were carried out using double ring. A general conclusion was that the edge effect was linearly related to time. Using minimizing root mean square error (RMSE) the two empirical coefficients of the model including γ and W*/W were determined. The values of 0.62 and 1.15 were determined for the two empirical parameters in the clay loam soil studied. The results showed that the RMSE and the absolute error (AE) were 0.0031 and5.9 %, respectively. Model sensitivity analysis showed that the lowest sensitivity was to initial water content and the highest sensitivity was to saturation water content. The approach leads to an infiltration function for irrigation furrows without the need to perform a fully two-dimensional simulation.
Keywords: Furrow irrigation, Two-dimensional infiltration models, Warrick model, Edge effect
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