A Combined Model for Operating Irrigated Agricultural Systems under Uncertainties

ABSTRACT IRRIGATION is a well-defined 1 sub-system in a comprehensive agricultural production system. Both of these systems are interrelated. An adaptable ad hoc linear model has been found to be a suitable model for planning and operating the entire system under uncertainties. This model is the framework of the irrigation sub-system. Unfortunately, many of the factors involved in irrigation create non-linear functions and thus, cannot be directly included in the linear model. This paper sug-gests using a linear model to solve the overall system for optimality, to check by a simulation technique whether the solution is feasible and meets the irrigation system set-up and requirements, and to change, if necessary, one or both of the systems in order to achieve the best feasible com-prehensive solution. The presented combined model has been carried out for 89 possible different cotton activities of 430 ha, reflecting various irrigation equip-ment and methods. The outcome pro-vides a detailed irrigation timetable and a list of the required parameters (pressure heads and discharges) for controlling the hydraulic network as well as the optimal overall solution.