Solar energy is the primary source for photosynthesis and transpiration in such a way as to assure the expression of the crop yield potential at a given site. The current methodology aims to ease the calculation of the water amount (liters/plant/day) necessary for a localized irrigation scheduling with a minimal loss possible at both citrus and apple trees orchards by means of usual available data, such as leaf area, global solar radiation flux density, net radiation and air daily mean steam saturation deficit. Taking into account that the localized irrigation system takes up far less water than sprinkler systems and also that the grant of water for irrigation is becoming more and more limited, such a work certainly comes to be of a great importance to assure the sustainability of the irrigated agriculture, especially at both arid and semi-arid regions. For the development of the proposed methodology a data set of sap flux measured by means of the heat flux approach in a citrus orchard, cultivar Tahiti, with leaf areas of 48 and 99 m², as well as in apple trees with leaf areas roughly of 5, 8, 9, 11, 16 and 21 m² was used herein. The obtained results revealed that it is rather feasible to estimate the amount of irrigation water throughout the whole citrus and apple trees cycle by means of the criterion based on the physiological variable input, which expresses the ability of the plants to converting solar energy into water taken up in the transpiration process at the sites in study.
solar irradiance; net radiation; modeling; water consumption; fruit trees
