Effect of complementary irrigation on yield components and alternate bearing of a traditional olive orchard in semi-arid conditions

Enrico M Lodolini,Mayyada Qutub,Mohammed Mutawea,Saed Ali,Fabio Pierini,Serena Polverigiani,Davide Neri

doi:10.5424/sjar/2016142-8834

Enrico M Lodolini, Mayyada Qutub + Show 5 more

Open Access

https://doi.org/10.5424/sjar/2016142-8834

Copy DOI

Abstract

Traditional olive orchards are usually not irrigated in the Mediterranean basin, but at those latitudes, the yearly rainfall is frequently insufficient to support equilibrated vegetative growth and high fruit and oil production. This three-year field study investigated the effect of complementary irrigation on olive tree vegetative growth, fruit and oil yield during a biennial alternate bearing cycle in a traditional grove under semi-arid conditions. Adult olive trees (Olea europaea L. cv. Nabali Baladi) were subjected to complementary irrigation in 2011 and 2012 ('on' and 'off' years, respectively) with 6, 10, 15 or 20 m3 of water per tree per season, which corresponded to 14.2%, 23.8%, 35.7% and 47.6% of the whole seasonal evapotranspiration (42 m3 of water per year), respectively. Rain-fed trees were used as control. In 2013, no complementary irrigation was supplied, and any residual effects on the yield components were determined. Results showed that none of the irrigation regimes affected vegetative growth, or olive fruit size (mesocarp and endocarp), as fresh and dry weights. The fruit and oil yield per tree increased compared to the rain-fed conditions only when the threshold of 15 m3 was exceeded, thus inducing a higher crop load compared to the rain-fed control during the 'off' and even further during the 'on' year. No residual effects were registered in 2013. The study showed that complementary irrigation of at least 35% of the seasonal water requirement can produce remarkable positive effects on fruit yield especially during 'on' bearing years.

Highlights

Olive (Olea europaea L.) has important physiological attributes that enable its survival and production in the drought-prone environments of the Mediterranean basin (Connor, 2005)
This three-year field study investigated the effect of complementary irrigation on olive tree vegetative growth, fruit and oil yield during a biennial alternate bearing cycle in a traditional grove under semi-arid conditions
No negative effects were registered on fruit and oil yields, nor on yield components compared to the 100% of ETc supply, by reducing the irrigation to a 35-50% of the ETc through regulated deficit or complementary irrigation in different areas characterized by a sub-humid Mediterranean climatic conditions (Alegre et al, 2002; Gucci et al, 2007; Servili et al, 2007; Caruso et al, 2013)

Summary

Introduction

Olive (Olea europaea L.) has important physiological attributes that enable its survival and production in the drought-prone environments of the Mediterranean basin (Connor, 2005). When regulated deficit irrigation in the reason of 25% of the ETc was applied in southern Spain (Mediterranean climate with average 496 mm rainfall during the three-years experimentation), fruit yield was significantly decreased in the ‘on’ year (high fruit production) and recorded no differences in low-yield year (‘off’ year) compared to 100% of ETc supply (Iniesta et al, 2009). A 70% of the total water requirement applied by regulated deficit irrigation did not affect the vegetative growth and fruit yield of young olive trees in semi-arid conditions (rainfall of 200-300 mm/year) of Morocco (Sikaoui et al, 2014) compared to full ETc return

Objectives

Methods

Results

Conclusion