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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #319138

Title: Influence of potential evapotranspiration on the water balance of sugarcane fields in Maui, Hawaii

Author
item OSORIO, J - Texas Agrilife Research
item JEONG, J - Texas Agrilife Research
item BIEGER, K - Texas Agrilife Research
item Arnold, Jeffrey

Submitted to: Journal of Water Resource and Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2014
Publication Date: 11/27/2014
Publication URL: http://handle.nal.usda.gov/10113/61276
Citation: Osorio, J., Jeong, J., Bieger, K., Arnold, J.G. 2014. Influence of potential evapotranspiration on the water balance of sugarcane fields in Maui, Hawaii. Journal of Water Resource and Protection. 6:852-868.

Interpretive Summary: Sugar cane production is ideally suited to the climatic conditions of Maui; however, irrigation is essential to satisfy the large water demand. In this study, we utilized the Soil and Water Assessment Tool (SWAT) to estimate the water balance of two sugarcane fields: a windy lowland field and a rocky highland field. To simulate the evaporative demand, three models for potential evapotranspiration were used: Penman-Monteith, Priestley-Taylor and Hargreaves. Wind speed was found to be a critical climatic variable, and the Penman-Monteith was determined to be the most accurate method with less than 10% error. These findings can be used to improve irrigation efficiency and determine optimum water management under varying elevation and climate.

Technical Abstract: The year-long warm temperatures and other climatic characteristics of the Pacific Ocean Islands have made Hawaii an optimum place for growing sugarcane; however, irrigation is essential to satisfy the large water demand of sugarcane. Under the Hawaiian tropical weather, actual evapotranspiration (AET) is the primary mechanism by which water is removed from natural and agricultural systems. The Hawaiian Commercial and Sugar Company (HC&S), the largest sugarcane grower of the Hawaiian Islands, has developed a locally optimized AET equation for the purpose of water management on its 184.3 km2 sugarcane plantation on the Island of Maui. In this paper, in order to assess the influence of AET on the hydrological water balance of the HC&S’ sugarcane cropping system, the performance of the HC&S method was compared with three physically-based methods: Penman-Monteith, Priestley-Taylor, and Hargreaves, as well as, to a set of historical pan evaporation data. A Soil and Water Assessment Tool (SWAT) project was setup to estimate the water balance in two sugarcane fields: a windy lowland field and a rocky highland field on a hill slope. Under Hawaiian weather conditions, wind speed was found to be the most influential climatic parameter over potential evapotranspiration (PET); therefore, the results with both Hargreaves and Priestley-Taylor underpredicted PET by approximately 30%, presumably because these methods do not take wind speed into account. The HC&S method was demonstrated to be the most accurate PET method compared to the other commonly used PET equations, with less than 10% error. Of the annual total water supply of 3400 mm, AET accounted for 75% - 80% of the total water consumption. These findings can be used to improve the irrigation efficiency as well as other management scenarios to optimize water use on the Island of Maui.