Irrigation Management in Olive Orchards for Oil Production

Traditionally, olives have been grown as a non-irrigated crop. Olives are well suited to Mediterranean dryland, with acceptable production and the ability to survive long periods of drought. However, experiments conducted for some time now have proven that even very small amounts of irrigation produce a considerable increase in olive grove yields (Carr, 2013). Until very recently a very small proportion of the more than ten million hectares of olive groves in the world were under irrigation, and most were under occasional support irrigation only. In the last few years several circumstances have coincided including a sharp rise in oil demand, intense drought conditions in production areas, the dissemination of localised irrigation techniques and the adoption of more intensive cultivation practises, which have led to much interest in the establishment of irrigation in olive groves (Orgaz and Fereres, 2004).

Although there is a wide body of literature on scientific irrigation scheduling in reference works, journal articles, symposium proceedings and extension publications, this situation is in contrast with the lack of knowledge by olive growers, irrigation engineers and water management authorities on olive grove irrigation requirements (Capra, 2003; Howell, 2007; Fereres, 2006; Pereira, 2002). Water management is critical for tree development and sustained high yields. Unfortunately, the often laborious and technical task of irrigation is frequently delegated to staff without the technical skills to assess water usage, soil moisture content or application uniformity. Poor water management can have a significant negative impact on orchard revenue. Both at the time of planning the transformation of an olive grove to irrigation and at the time of applying irrigation, a set of questions arise that must be solved before any optimum irrigation strategies are determined. These questions include:

• What are the seasonal irrigation requirements for maximum production?
• When should such water be applied?
• How to effectively evaluate the irrigation operations?
• What are the most appropriate techniques to irrigate when there is limited water availability?
• Which are the most relevant areas for future study and research?