The effect of irrigation schedules on the water relations and growth of a young olive (Olea europaea L.) orchard

In recent years there has been a notable worldwide increase in the amount of land devoted to olive orchards. Most of these new orchards are irrigated and represent large financial investments. The irrigation of young olive trees should reduce the period during which their production is small or non-existent. Although the water requirements of young olive orchards are thought to be low, little is in fact known in this regard. In the present work, three irrigation treatments (100, 75 and 50% coverage of water needs) were designed using the Orgaz method, and their effects on young olive trees tested in different plots over a period of 3 years. The 50% deficit treatment was designed to provide the trees with an amount of water in the region of that stipulated by the FAO method, the most commonly used irrigation scheduling system for olive orchards. No significant differences in shoot water potential nor abaxial leaf conductance were seen between the trees receiving the different treatments. However, canopy volume and shoot growth were affected. These results indicate that the traditional FAO model, which would have supplied about 35% of the water supplied by the Control treatment, may well reduce the economic benefits to be derived from young olive orchards.