A regulated deficit irrigation strategy for hedgerow olive orchards with high plant density

There is not a consensus on the best irrigation approach for super-high density (SHD) olive orchards. Our aim was to design and test a regulated deficit irrigation (RDI) strategy for a sustainable balance between water saving, tree vigour and oil production. We tested our RDI strategy for 3 years in an 'Arbequina' orchard with 1,667 trees ha(-1). Two levels of irrigation reduction were applied, 60RDI and 30RDI, scaled to replacing 60 % and 30 %, respectively, of the of irrigation needs (IN). We also had a full irrigation (FI) treatment as control, with IN totalling 4,701 m(3) ha(-1) The 30RDI treatment showed the best balance between water saving, tree vigour and oil production. With a yearly irrigation amount (IA) of 1,366 m(3) ha(-1), which meant 72 % water saving as compared to FI, the reduction in oil yield was 26 % only. Our results, together with recent knowledge on the effect of water stress on fruit development, allowed us to suggest a potentially improved RDI strategy for which a total IA of ca. 2,100 m(3) ha(-1) was calculated. Both some management details and the benefits of this suggested RDI strategy are still to be tested.