Modelling of Citrus Evapotranspiration Under Different Water Supply Conditions: Case Study of Beni Khalled, Tunisia

Abstract

In Tunisia, under future climate scenarios, it is expected that the water balance deficit will increase. An accurate estimate of crop water consumption is necessary for an appropriate management of available water. The objective  is to calibrate an hourly evapotranspiration (ET) model based on the Penman-Monteith equation, for citrus orchards in Cap-Bon region, under different levels of water supply conditions using the Bowen Ratio as a stress indicator. A significant relationship between this indicator and one of the calibration coefficients was found. This means that this coefficient varies according to stress level. A comparison between filtered Eddy Covariance measurements (LE) and simulated ET was performed. Values of Root Mean Square (RMSE) varied between 0.09 mm for no-stress conditions and gradually decreased with each stress level to reach 0.02 mm for the most severe stress level. This means that a good correlation between observation and simulation of ET is confirmed.

Keywords: evapotranspiration, Hourly model, Eddy Covariance, stress, Citrus