Short-term physiological recovery and yield response of hedgerow olive orchards after prolonged water stress

The increase of drought periods implies that olive orchards could suffer severe water stress conditions for several years which could limit yield response when irrigation resumes. The aim of this work was to describe in olive trees the long-term effect of 4 years of drought on the first season of irrigation. The experiment was performed in Seville (Spain) during the 2024 season in a 6-year–old hedgerow olive orchard (cv Manzanilla de Sevilla). The irrigation treatments were: Control, full irrigation; Regulated deficit irrigation (RDI), with a period of water stress during pit hardening, and Recovery, irrigated as RDI after a four drought seasons. Several measurements of fruit development, water status and vegetative growth were determined. Water relations data suggested that Recovery trees had no physiological limitations due to the previous drought periods. The number of inflorescences was reduced in the Recovery treatment, but this was related to previous season conditions and was not a long-term effect. Recovery trees decreased yield amount but not quality, mainly because a crown volume lower than the Control at the beginning of the experiment. On the opposite, RDI presented the same yield as Control, with 47% less irrigation volume but similar crown volume. As a consequence, irrigation water productivity exhibited marked contrasts, with maximum values in RDI reaching 23.6 kg/m³ , better than the Control (13.4 kg/m³) and Recovery treatment (15.3 kg/m³). Maintain an optimum crown volume in period of drought would secure a fast recovery of yield when irrigation was resumed even with deficit amounts.