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Résumé :
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Irrigation scheduling with pressurized systems is being implemented successfully in many countries of the world.However,there is need to propose a surface irrigation scheduling program that is significantly better than those employed to date.For surface irrigation systems,which are hydraulically more complex than pressurized systems,mere advice regarding when and how much to irrigate is not sufficient.An effective surface irrigation scheduling program must also advise the farmers how long to irrigate for whatever discharge rate is available et the time of irrigation.This book describes the procedure for undertaking surface irrigation scheduling.As there are different surface irrigation sub-systems,corresponding approaches are separately.Of course,the whole surface irrigation scheduling procedure is primarily based upon the volume balance technique described in chapter 4.In the last decade or so,there have been rapid advances made in the mathematical modeling of the surface irrigation system.The latest models,such as those called full hydrodynamic, zero-inertia or kinematic wave,have been applied very successfully to predict the surface irrigation behavior.However,the level of accurate predictions in each case is obviously going to be a function of the input data.If the data given do not correspond to a particular soil,crop and irrigation event,these advanced modeling techniques are not going to be of any real help.Hence,in order to initiate a process to utilize the state-of-the-art knowledge in surface irrigation modeling,some ideas have been presented in chapter 5.The scope of the zero-inertia modeling technique is expanded to generalize the functional relationships developed using the techniques described in chapters 2 and 3.Finally,the chapter presents a scheme to use dimensionless design charts developed using a non-dimensional version of the zero-inertia model for surface irrigation scheduling.Various methods given in chapter 5 are not in any way the "final word" in the field of surface irrigation scheduling--but they do provide a good "starting point" in this direction.Chapter 6 describes the most commonly used irrigation performance indices.Knowledge of such parameters is considered essential for characterizing hydraulic performance.
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