ASSESSING FAO-56 MODEL TO ESTIMATE TABLE OLIVE WATER CONSUME UNDER SOIL WATER DEFICIT CONDITIONS

Agro-hydrological models can be considered an economic and simple tool to quantify crop water requirements. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system. Although very reliable, due to the high number of required variables, simplified models have been proposed as simple tools to quantify crop water consumes. The main aim of the paper is to assess, for a Sicilian orchard of table olive, the suitability of FAO-56 agro-hydrological model to estimate the crop transpiration under soil water deficit conditions. The model validation is carried out by means of measurements of sap-flow and soil water contents, acquired during three years of field observations. An amendment of the model is suggested in order to take into account the water stress function and the soil water uptake ability as experimentally evaluated. The results show that the modified model improves the estimation of crop transpiration and soil water content, considered that the associated RMSEs resulted higher than the corresponding values obtained with the original version of the model.