Nonlinear programming model for extensive irrigation

In regions where irrigation water supply is less than the required amount, extensive but deficit irrigation becomes unavoidable, unless the irrigated area can be limited to ensure full supply. When reliable dated crop-water response (DCWR) functions are available, a scientific planning of deficit irrigation schedules can be undertaken. This paper presents the formulation of a nonlinear programming (NLP) problem for identifying optimal cropping pattern as well as optimal deficit irrigation schedule along with its application to a minor irrigation system. The model indicates, for the case studied, that an increase in the cropped area by approximately 50% is possible over that underintensive irrigation approach. In terms of the net monetary return from the system, it means an increase of approximately 20%. The adoption of extensive irrigation policy in such a setting is seen to be desirable.