Calibration Methods to Estimate Reference Crop Evapotranspiration and Calculated Potential Water Requirements of Olive Plant in Kermanshah Province

Mirmousavi, Husayn; Panahi, Hamid; Akbari, Hamid; Akbarzadeh, Younes

Calibration Methods to Estimate Reference Crop Evapotranspiration and Calculated Potential Water Requirements of Olive Plant in Kermanshah Province

Document Type : Research Paper

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Abstract

Estimating thewater requirement is among themost important factors inthedesign ofirrigationand water resources management. Todetermine thewater requirement, the evaporation-transpiration point of thereference crop should be estimated. Given that avariety of methodshave beenrecommended in this regards, selectingthe appropriate methodis a hard and complex task.Inthisstudy,fiveselectedstationsinKermanshah provinceduring theperiodbetween 17 and54yearswere used. Five methods including FAO - Penman-Monteith, Thornthwaite, Modified Blaney-Criddle, modifiedHargreavesandPenman have been used to do the needed calculations which are done based onmonthly and annualdata. Thecalculatedvaluesofthe potential evaporation-transpirationandtherecommendations of theWorld Meteorological Organization indicated that of the fivemethods mentioned aboveFAO - Penman-Monteithprovidesa moreaccurate estimate. Theresultsshowed thatthemonthly and annualmaximum ET₀ were8.5and48.9millimeterswhich was forRavansarstationand the minimumorder of5.8and38.4mmwhich was experienced in Kangavarstation, and finally it showed that the maximumannualwater requirementforRavansarstationis923.3mm.

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