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چکیده
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One of the strategies for increasing water use efficiency and reducing deep percolation drip irrigation systems is considering the patterns of moisture redistribution after cut-offing the irrigation process. An experimental study was conducted in the present research to evaluate the moisture redistribution process under surface and subsurface pulse drip irrigation systems and developing new regression-based methodologies for estimating moisture redistribution dimensions using both the soil and system parameters together. A physical model was made and the experiments were performed on three different types of soil texture (light, medium, and heavy) with three emitter flow rates (2, 4, and 6 lit/hr) in three emitter installation depths (0, 15, and 30 cm). The experiments were conducted for both continuous (CI) and pulse (PI) irrigation modes. The results showed that significant amounts of wetting dimensions and wetted area of the moisture bulb are related to post-cut-offing stage. Then, using the nonlinear regression analysis, several models were proposed to estimate the horizontal and vertical redistribution pattern as well as the wetted area (upper and lower parts of the emitter). The comparison of the measured and the stimulated values indicated that the non-linear regression models simulated the parameters associated with redistribution, accurately.
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