Five-year growth and yield response of two young olive cultivars (Olea europaea L., cvs. Arbequina and Empeltre) to soil salinity

Olive is considered moderately tolerant to salinity, but most studies are short in duration and report its tolerance on the basis of targeted irrigation water salinity (ECiw) rather than on measured root zone soil salinity (ECe). We evaluated the growth (tree height and trunk diameter) and yield (fruit and oil weights) response of two drip-irrigated young olive cultivars (Arbequina and Empeltre) subject to three ECiw treatments (2, 4 and 10 dS m(-1)). The ECe of 23 Arbequina and 20 Empeltre trees was intensively monitored during the 2003-2007 study period using an EM38 sensor and converting its readings into ECe through sensor calibration. For growth, the slopes of the linear regression equations (-3% to -5%) and the ECe(50) estimates (12.5-14.0 dS m(-1)) were similar in both cultivars and vegetative traits. Likewise, for yield the slopes of the linear regression equations (-4% to -7%) and the ECe(50) estimates (7.9-9.6 dS m(-1)) were similar in both cultivars and yield traits. Based on mean ECe(50) estimates, olive vegetative growth was ranked as moderately tolerant (mean ECe(50) = 13.2 dS m(-1)), whereas olive and oil yields were ranked as moderately sensitive (mean ECe(50) = 8.7 dS m(-1)).