Yield and oil quality of young olive trees grown under different irrigation regimes

The aim of the paper is to contribute to the improvement of our knowledge on water requirements and management of olive trees grown in an inland hilly area of southern Italy. The field trial was carried out in a drip irrigated olive orchard planted in 1992 at the C.N.R. Irrigation Institute experimental farm (41° 06' North, 14° 43' East and; 250 m above sea level). The training system used was a monocone, planted to a density of 6 x 3 m. Three table and both table and oil cultivars (Ascolana tenera, Kalamata, and Nocellara del Belice), grafted onto DA 12-I° rootstock, were tested under four water regimes: T0 (rainfed control), and T1, T2 and T3 which received a water depth equivalent to 33,66 and 100% of estimated crop evapotranspiration, respectively. After the third year of irrigation treatments and the second year of fruiting, results showed a yield enhancement as crop water availability increased. The yield behaviour was primarily attributed to an increase in mean fruit weight and to a larger number of fruits per plant in the two most irrigated treatments. No differences were detected among irrigation regimes for oil and its fatty acid composition, while the polyphenol content decreased as the water supply increased.