Controlled deficit irrigation for orange trees in Mediterranean countries

Orange tree cultivation is widespread throughout the world, and the Mediterranean Basin is an important producer. The Mediterranean climate is characterised by scarce water resources that limit crop sustainability. In this study, controlled deficit irrigation is evaluated as a water conservation strategy with the aim of improving crop sustainability. To accomplish this objective, a trial is conducted in southern Spain for nine months with four treatments (five repetitions each): normal irrigation (the control variable), deficit irrigation and two treatments of controlled deficit irrigation. In relation to the crop, physiological parameters, production and fruit quality were analysed, all with respect to water usage. Finally, an efficiency curve was established for water usage, which determined the optimum water usage to be between 700 and 800 mm. It has been experimentally determined that controlled deficit irrigation reduces water used by 5% compared with constant deficit irrigation and improves productivity by 4%. The primary conclusion is that controlled deficit irrigation strategies present certain advantages to crop management and are an alternative to reducing water inputs with minimal effects on production and fruit quality, thus contributing to crop sustainability. (C) 2017 Elsevier Ltd. All rights reserved.