Applicazione di un modello integrato per la stima dell'evapotraspirazione di piante d'olivo (Olea europea L.)

The correct estimation of actual evapotranspiration (ETa) on heterogeneous areas requires the knowledge of the contribution of different ecosystem components (i.e. bare soil, grasses and trees). The availability of various monitoring systems (eco-physiological, agro-meteorological and from remote sensors) offers the opportunity to integrate ground measurements and remotely sensed observations to improve the accuracy and reliability of water budget models. In this paper, the preliminary results related to the use of a NDVI-derived crop coefficient to guide a local water balance model (WINETRO) and estimate the olive trees ETa are shown. The integrated ETa estimates for the olive trees, grasses and bare soil (resulting from the weighted sum of olive, grass and soil contributions) and the olive tree transpiration are compared, respectively, to data collected by soil moisture sensors at two different depths (10 and 30 cm) and to those measured by sap flows. The analysis confirms the possibility to get significant advantage from integrated techniques in the evaluation of transpiration and water requirements of many extensive Mediterranean olive crops.