Effects of different irrigation regimes on plant water status, yield and oil quality of two olive cultivars

Hedgerow olive orchards have become the most common orchard design in new plantings. Since the hedgerow olive orchard system is 20 years old, new research is needed to improve and adapt it to local conditions with profitability. The present work shows results obtained in the 2015/ 2016 crop season after 2 years with different irrigation treatments on two olive cultivars, 'Arbequina' and 'Cornicabra', cultivated in a super-high-density (SHD) orchard (1481 trees ha(-1)) planted in 2003. 'Arbequina' is the most common cultivar in SHD systems, and 'Cornicabra' was chosen as the most important cultivar in central Spain. The irrigation treatments were: (1) T-100, 100% of ETc, where ETc is the crop evapotranspiration; (2) T-130, 130% of ETc; (3) T-70, 70% of ETc; (4) RDI, regulated deficit irrigation (40% of ETc between 15 July and 1 September, 100% of ETc for the rest of the experiment). Fruit fresh weight, fruit water content, oil content, oil production and maturity index were evaluated at harvest (last week of October for 'Arbequina' and 2 weeks later for 'Cornicabra'). Total phenols, carotenoid and chlorophyll pigment contents were determined. 'Cornicabra' showed higher values of fruit weight, oil content, total phenols and chlorophylls, whilst a higher carotenoid content was found in 'Arbequina'. Higher doses of irrigation produced heavier fruits with higher water content. T-70 treatment gave higher total phenols content, while RDI increased both types of pigments. Although there were no statistically significant differences between levels of irrigation in oil production, a decreasing tendency was detected in T-70 in relation to the other treatments. Besides higher water content in fruit, T-130 did not appear to be a better treatment than T100 by any indicator.