Effect of regulated deficit irrigation strategies on productivity, quality and water use efficiency in a high-density 'Arbequina' olive orchard located in an arid region of Argentina

VITA FACUNDO; PACHECO DANIELA; OLGUIN ALFREDO; BUENO LUIS; CARELLI AMALIA; CAPRARO FLAVIO

ACTA HORTICULTURAE

International Society for Horticultural Science

Año: 2011 vol. 888 p. 81 - 88

0567-7572

Most Argentinean oliviculture is located in a semi-arid region fully dependent on irrigation. Regulated deficit irrigation (RDI) strategies represent a management tool to reduce water use and to even improve some oil quality parameters. Different irrigation treatments, based on RDI strategies, were applied over 2 years to an intensive olive orchard (cultivar ‘Arbequina’): (T3) RDI from fruit set to harvest, (T2) RDI from pit hardening to harvest (2007/08), RDI during the pit hardening period (2008/09), and (T1) fully irrigated as a control. In T2 and T3, water deficit meant a 40% (2007/08) and 30% (2008/09) reduction of field capacity soil moisture level. In the 2007/08 season, the amount of water applied from fruit set to harvest was reduced by 58% and 67% of the fully irrigated treatment in T2 and T3, respectively. In 2008/09 the water applied was reduced by 30% and 62.5% in T2 and T3, respectively. There were no differences in olive fruit and oil yields between treatments in 2007/08. In the next season, T3 had lesser oil yield than the other treatments. In both crop seasons the water use efficiency (WUE), expressed oil yield (kg) per mm of irrigation water, was higher in RDI treatments, but there were no differences between them. The oleic acid, total phenol and total tocopherol contents, MUFA/PUFA ratios and OSI, increased in both RDI treatments during the 2007/08 season. In 2008/09, only T3 showed higher oleic acid content and MUFA/PUFA ratios. Furthermore, increased amounts of total phenol and OSI were observed in T2 but were not as high as those reached by T3 treatments. The shorter deficit irrigation period for T2 in the 2008/09 season did not affect fatty acid compositions but did modify antioxidant compounds in relation to the well irrigated treatment. Taken together our results suggest that an RDI strategy applied from fruit set to harvest decrease oil yield but improved the WUE and certain olive oil quality parameters.