Use of optimal control in deriving water conserving irrigation schedules based on state events

Abstract

Continued irrigated production in the Oklahoma Panhandle is threatened by the declining groundwater supply and costs of pumping groundwater. A computerized grain sorghum plant-growth model using daily weather observations and optimal control theory is used to derive irrigation schedules based on soil moisture deficiency at different stages of grain sorghum plant growth. When the optimal control irrigation schedules are compared to a fixed day interval-scheduled irrigation practice, the optimal control irrigation schedules reduce water and energy use while maintaining, and even increasing, net returns to the producer.