Water productivity in olive trees: Current advances and new perspectives

Water productivity (WP) in olive orchards is crucial for sustainable agriculture, particularly in water-scarce Mediterranean regions affected by climate change. This review examines strategies to improve WP, including deficit irrigation (DI), sensor-based precision irrigation, orchard management, and climate adaptation. Regulated (RDI) and sustained (SDI) deficit irrigation optimize water use without major yield or oil quality losses. RDI applied during less sensitive drought stages (e.g., pit hardening) can improve WP by up to 20 %, while also enhancing the phenolic content of the olive oil. However, long-term impacts on plant vegetative response, longevity and soil health require further study. Irrigation application thresholds were identified, beyond which gains in WP decline. However, these thresholds should be regarded as indicative benchmarks of irrigation eff iciency rather than explicit management targets, as WP alone does not necessarily reflect maximum yield or oil quality. Physiological indicators, such as stem water potential, are proving valuable for fine-tuning irrigation decisions, though threshold values vary according to cultivar and environmental conditions. Plant-based sensors—including trunk dendrometers, microtensiometers, leaf patch clamp pressure probes, and sap flow sensors—show promise for monitoring plant water status, but cost, calibration, and data interpretation challenges currently limit widespread implementation. These measurements also depend on environmental conditions, cultivar, and water status. Orchard management practices, such as increased planting density and the use of mulches or cover crops, could contribute to WP improvements by reducing evaporation and optimizing resource partitioning, but further research is needed on the subject. Climate change projections suggest an overall decrease in WP due to increased temperatures, reduced precipitation and water stress, though there is regional variability. To ensure sustainable olive production under water-limited and changing climatic conditions, a holistic approach combining irrigation strategies, technological innovation and adaptive management is essential.