Deficit irrigation during oil synthesis period did not affect vegetative growth and return bloom in olive tree ('Arbequina')

During 2011, 2012 and, 2013 a field experiment was carried out in two hedgerow 'Arbequina' olive orchards, planted at a spacing of 4x2 m (1250 trees ha(-1)) and placed near each other, in order to determine the effect of deficit irrigation during the late summer-autumn period, which is the oil synthesis period, and it is the floral initiation period for the next season production. Four irrigation treatments were evaluated. The control treatment (CON) was irrigated, to maintain the root zone close to field capacity. Three other treatments were irrigated as CON except from August 23 until harvest received irrigation rates of 65-70% CON (RDI-1), 40% CON (RDI-2), and 12-17% CON (RDI-3). Measurements of stem water potential (Psi(t)) were taken alongside the experimental period as an indication of the water status of the olive trees. The impact of water stress in next year vegetative growth, flower initiation and fruit set was evaluated. During the experiment the lowest water potential values were achieved in the most stressed treatment, having values as low as -6.0 MPa. Results showed that there were no significant differences between treatments in nodes formed, buds initiated, inflorescence fertility, fruits per fertile inflorescence, fruit drop and fruits per bud. According to the results obtained there is no connection between water stress during late summer and autumn and next season vegetative growth or blooming.