Irrigation Decision Rules for Cottongrowing in the Brookstead Area of the Darling Downs

A decision problem faced by cottongrowers using irrigation is that of deciding the soil moisture level at which irrigation should occur. A simulation model was developed so that the effect on cotton yield of irrigation at different soil moisture levels could be explored. The output from the model was used to develop relationships enabling the determination of an optimal decision rule. The results indicate that under most situations heavy irrigation in the period "first open flowers to first open bolls" will be profitable.