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Effects of extreme drought on the vegetative and productive behavior of olive 'Istrska belica'

Podgornik, M., Bandelj, D., Bucar-Miklavcic, M., Hladnik, M., Bester, E., Valencic, V., Knap, T., Miklavčič Višnjevec, A., Baruca Arbeiter, A., Zupanc, V., Pintar, M., Butinar, B.
Acta horticulturae 2018 no.1199 pp. 63-68
climate change, crop yield, cultivars, deficit irrigation, drought, evapotranspiration, flowering, fruit set, fruits, growing season, irrigation management, lipid content, olive oil, olives, trees, water supply, Mediterranean region, Slovenia
The northern Mediterranean region's vulnerability to climate change has been highlighted by the increased occurrence and intensity of agricultural droughts. Consequently, there has been an enormous increase in interest in the deficit irrigation approach. To determine the vegetative and productive response of local cultivar 'Istrska belica' to variable water quantities applied during the extreme drought season, an experiment was set up in an olive grove located at southwestern Slovenia. Four irrigation treatments were applied during the growing season, with water applied to the amount of 15, 33, 40, and 100% ETc (crop evapotranspiration), and rainfed conditions. The irrigation regime significantly affected shoot length, fruit set, number of fruit per shoot, and olive production. Despite the fact that 2015 was characterized by extreme weather conditions, no differences in crop yield were found among rainfed and deficit irrigation treatments (15, 33, and 40% ETc). A different pattern was observed in terms of the content of olive oil. Olives from trees grown under rainfed conditions exhibited lower oil content than olives produced under the different irrigation treatments. Although the rainfed treatment resulted in the lowest oil yield, the shoot growth of trees under rainfed conditions was greater than that of trees receiving 15, 33, 40, and 100% ETc irrigation treatments. The results showed that flowering was not significantly affected by water supply.