The aim of this study was to estimate water requirements for stevia (Stevia rebaudiana Bertoni) crop. This research was conducted in the Regional Center of Agronomic Research of Rabat in Morocco (INRA). The data were collected daily at 8 am, from 10 June to 28 August 2014. The crop maximum evapotranspiration (ETm) was obtained from the water balance method, the reference evapotranspiration (ET0) is estimated using a valid FAO-56 Penman-Monteith equation and the pan evapotranspiration (ETp) is calculated by class ‘A’ pan evaporation. The average maximum evapotranspiration of stevia along the entire cycle of 80 days is 4.36 mm/day with a maximum value of 6.50 mm/day. The FAO-56 Penman-Monteith and Pan evaporation methods showed high correlation with the water balance data with a coefficient of determination of R2 = 0.5548 (slope = 0.432) for ETp and R2 =0.4943 (slope = 0.3001) for ET0. The values of the crop coefficients of three stages (first-stage, second-stage and third-stage) for KCp and KC0 are 0.86, 1.00, 1.15, and 0.83, 0.94, 1.10, respectively. The plant height, stem diameter and dry leaf yield of stevia were 75.33±4.44 cm, 12.33±0.79 and 2.03± 0.38t/ha, respectively. The values obtained during this study allow having better irrigation scheduling and water management.
