You must find yourself an improving criteria and a set of constraints describing the problem where the decision variables, or at least a subset, be discrete/integer. Then, applying a Branch & Bound algorithm will allow you to sequentially solve a linear relaxation of the problem, and find easier sub-problems aiming at finding integer solutions while improving lower and upper bounds (derived from feasible and relaxed solutions of the original problem). Once all possible branches had been examined or a certain tolerance level be attained the problem will stop and the solution will be the desired optimal irrigation schedule.

It is necessary to avoid severe water stress during critical crop growth stages. Soil moisture should be monitored and number and dates of irrigation may be determined using models. The method of application may be suggested based on status of availability. If there is a shortage of water, then efficient irrigation method may be drip method. Or, surface furrow irrigation may also be advocated.