WRRCTR No.56 Estimating the Productivity of Irrigation Water for Sugarcane Production in Hawaii

Abstract

This study has concentrated on the development of an operational model for determining the productivity of irrigation water in sugarcane production in Hawaii. Data were collected from sugar plantations located in two sugar-producing areas chosen to represent the various sugar-producing conditions in the state. Area I depended exclusively on water from artesian wells for irrigation. Irrigation in Area II depended mostly on stored surface runoff rainfall and is supplementary in nature. Both areas differ in their physical terrain. Of necessity, the study draws heavily from and builds on the experiences of previous investigations in the general areas of agricultural economics and plant sciences. From an integration of these ideas,the modified composite variable was developed as a measure of water adequacy in cane production. Most of the information required to construct this variable is available from management records. Pan evaporation data were incomplete because standard evaporation pans were only recently installed and then only in a few areas. To overcome this difficulty, techniques were developed to estimate evapotranspiration for the two study areas utilizing available pan data together with other relevant indicators.