Optimal Irrigation Depths — A Method of Analysis

Abstract

The concept of a system optimal depth (SOD) is derived, where the SOD represents that average depth of water that must be infiltrated by an irrigation to bring about the maximum net income for that particular irrigation. It minimizes the combined losses due to deficit irrigation and excess irrigation for the particular irrigation system that is being used. The concept is demonstrated for two particular irrigation practices: (1) When the irrigation requirement is fixed, the water distribution as a function of time is known, and the optimal application depth is to be determined; and (2) when the final water distribution and the average depth of application is fixed and the optimal requirement is to be determined. Examples of how the concept can be used to determine optimal operation procedures are shown.