Document Type : Research paper
Authors
1
Former Ph.D. Student of Department of Horticultural Science, Agricultural Science and food technology Faculty, Science and Research Branch, Islamic Azad University, Tehran, Iran
2
Department of Horticultural Science and Engineering, Faculty of Agricultural Sciences and Engineering, Razi University, Kermanshah, Iran
3
Department of Horticultural Science, Faculty of Science and Agricultural Engineering, Campus of Agriculture and Natural Resources, Tehran University, Karaj, Iran.
4
Department of Horticultural Science, Agricultural Science and food technology Faculty, Science and Research Branch, Islamic Azad University, Tehran, Iran.
10.22059/ijhst.2025.385084.960
Abstract
Deficit irrigation as a water-saving strategy for olive trees in semi-arid regions of Iran has received limited research attention. This study addressed this gap by investigating its effects on the ‘Zard’ olive cultivar over two years. Six irrigation regimes were compared, including control (C) (100% of crop evapotranspiration (ETc) throughout the growing season), Sustained Deficit Irrigation 1 (SDI1) (75% ETc throughout the growing season), Sustained Deficit Irrigation 2 (SDI2) (50% ETc throughout the growing season), Regulated Deficit Irrigation 1 (RDI1) (75% ETc from 4 to 9 weeks after full bloom), Regulated Deficit Irrigation 2 (RDI2) (50% ETc from 4 to 9 weeks after full bloom) and Regulated Deficit Irrigation 3 (RDI3) (50% ETc for 2 weeks before harvest). Sustained deficit irrigation (SDI1 and SDI2) and RDI2 negatively impacted flower number and perfect flower formation (except RDI3) in the second year. Fruit set was not significantly affected by RDI1 and RDI3 compared to the control, but SDI2 significantly reduced both fruit weight and pulp-to-pit ratio. Fruit yield and oil content were negatively affected by SDI1, SDI2, and RDI2 compared to the control. However, RDI1 and RDI3 showed no significant difference from the control in these aspects. Regulated deficit irrigation (RDI1 and RDI3) with a minor reduction in applied water is recommended for semi-arid regions (excluding Mediterranean climates) to achieve high fruit yield and oil content while conserving water.
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