Water footprint and performance assessment of a table olive cultivar (Olea europaea L. ‘Konservolea’) under various irrigation strategies

Greece produces 10% of the world’s table olives and is ranked as the second most significant global exporter for this product. The three major table olive cultivars in Greece are ‘Halkidiki’, ‘Konservolia’ and ‘Kalamata’. Traditionally, growers in Greece depend on rain to cover the water needs of olive orchards. This strategy is rapidly changing during the last decades, as growers shift to irrigation to confront prolonged drought periods and intensify the cultivation. But as irrigation is mainly managed empirically, it results in drawbacks including high water consumption with associated effluents which raise serious environmental concerns. In the present work, three irrigation practices were studied for three consecutive years on a typical ‘Konservolea’ orchard in Arta, Epirus (northwestern Greece): a) rainfed, b) irrigation based on growers’ experience (typical practice), and c) irrigation based on recommendations from a decision support system (DSS) which is based on UN’s Food Agriculture Organisation (FAO) guidelines for the determination of soil water depletion. The water footprint (WF) of the different irrigation practices was assessed and related to the trees’ performance regarding development, physiological status, yield and fruit quality. The results showed that not only the irrigated olive trees performed better compared to the rainfed ones in terms of development, physiological status, yield and fruit quality, but they also resulted in a smaller water footprint due to much higher yields as compared to the rainfed trees. Among the two irrigated regimes (typical practice and DSS), the irrigated following the typical practice exhibited a slightly higher yield but it did not surpass the DSS treatment in fruit quality, development and physiological status. Considering also the lower WF of the DSS treatment (970 vs. 973 m³ t^‑1 of the typical practice and 1782 m³ t^‑1 of the rainfed), we conclude that the DSS irrigation can successfully replace typical practice in irrigation management, ensuring similar performance accompanied by smaller environmental impact.