The objective of this study was to determine the water requirement and the crop coefficients (Kc) values for apple trees cultivated in Vacaria, RS. The study was conducted at the Experimental Station of Temperate Fruits (EEFT) of Embrapa Grape and Wine, located in Vacaria, RS, in plants of the cultivar 'Royal Gala' (Malus domestica) on the rootstock M9. The soil water matric potential values, that were determined employing tensiometers, were used to obtain the soil moisture and the monthly soil water balance. The water consumption of the culture ranged from 0.3mm day-1 to 4.5mm day-1, with an average of 1.9mm day-1. The crop coefficient (Kc) presented a quadratic trend, ranging between 0.19 and 0.88, with mean value of 0.58.
apple; Malus domestica; evapotranspiration
