Developing Equations to Predict the Pattern of Soils Moisture Redistribution in Surface and Subsurface Drip Irrigation Systems Using Dimension Analysis

Modelling moisture redistribution in soils after irrigation cutoff and utilizing this parameter in system design can be considered as one of the criteria for improving water productivity in surface and subsurface irrigation systems. In this study، experiments were carried out in a transparent plexy-glass tank (0. 5m. 1. 22m. 3m) using three different soil textures (fine، heavy and medium). The drippers were installed at 4 different soil depths (surface، 15cm، 30ch and 45cm). The emitter outflows were considered 2. 4 and 4 lit/hr with irrigation duration of 6hr. Then، using the- theorem of Buckingham and Dimension Analysis (DA)، equations were developed to estimate the pattern of moisture redistribution (horizontal and vertical) after irrigation cutoff in surface and subsurface drip irrigation systems. The results of the comparisons between simulated and observed values showed that these equations are very capable in predicting the pattern of moisture redistribution in different directions. Considering these equations in designing surface and subsurface drip irrigation systems could improve system performance.