Sustainable Fruit Production in Mediterranean Orchards Subjected to Drought Stress

Abstract

Drought stress is the main cause of reduced fruit tree growth and productivity in Mediterranean semi-arid regions and causes a complex of responses at molecular, cellular, physiological and developmental level. In particular, the response of fruit trees to water scarcity is a species-and cultivar-dependent and a series of studies have been carried out to clarify and deepen the mechanisms of their adaptation, avoidance, resistance or tolerance against drought. Considering that 16% of the total cultivable land of the Mediterranean area is occupied by fruit crops, the choice of an appropriate and rational irrigation management is of key importance. Furthermore, plant water status in an orchard is related to many biotic and abiotic factors , such as the amount of light intercepted, plant densities and canopy architecture, which play a key role in determining orchard productivity and fruit quality. The recent research on the physiology of fruit trees and on soil chemical and biological fertility in fruit orchards have revealed that sustainable and innovative soil management systems, with a particular emphasis on water management (e.g., sustained defi cit irrigation, regulated defi cit irrigation and partial root-zone drying), can determine an optimal plant nutritional equilibrium, avoid nutrients accumulation and leaching risks, improve irrigation effi ciency and prevent soil erosion and root asphyxia. The application, optimization and innovation of sustainable agricultural techniques with a low negative environmental impact allow to recover or increase the normal levels of total fertility in fruit agro-ecosystems, so