Impact of survival irrigation on a mature super-high-density olive orchard

Abstract Over the past two decades, climate change projections for the Mediterranean Basin have indicated increasing evaporative demand and decreasing soil water availability, threatening olive production and emphasizing the need for adaptation strategies such as deficit irrigation. This study evaluated a deficit irrigation strategy for super-high-density olive orchards under extremely limited water availability, termed survival irrigation (S treatment). The strategy was applied to a 6–7-year-old ‘Arbequina’ orchard in southern Spain (1667 trees ha⁻ 1 ) during 2023 and 2024, supplying only 25.6 % and 15.5 % of crop irrigation requirements, respectively. A fully irrigated control based on the FAO-56 crop coefficient approach (FI CC treatment) was also included. The effects of survival irrigation on tree water status, gas exchange, vegetative growth, fruit and oil production, and nutrient uptake were assessed. As expected, the applied water volumes were insufficient to avoid prolonged periods of severe water stress throughout the growing cycle. During these periods, trees reached leaf water potentials as low as − 7.2 MPa and showed very low stomatal conductance ( g s ) and net photosynthesis ( A N ), frequently around 0.05 mol m⁻ 2 s⁻ 1 and 5 μmol m⁻ 2 s⁻ 1 , respectively. Despite the severe stress, survival irrigation prevented nutrient deficiencies and maintained limited vegetative growth and fruit production. Yields under survival irrigation reached 47 % of those under full irrigation, while oil yield in 2024 represented 41.6 % of the control. Trunk dendrometers and leaf turgor pressure sensors proved effective for monitoring tree water stress under survival irrigation conditions.