Effect of Deficit Irrigation under Subsurface Drip Irrigation in Gravel Soil on Yield and Physical Properties of Olive Fruit  Zard Cultivar

This study was conducted to quantify the effect of different irrigation levels on yield and physical properties of the olive fruit under subsurface drip irrigation in a gravel soil. Irrigation levels were included 20, 40, 60, 80 and 100% of crop evapotranspiration. The irrigation treatments arranged in a randomized complete block design with three replications. Physiological characteristics such as moisture of leaves and branches during the growing season, and yield and fruit physical characteristics at harvest date were measured.The effect of irrigation levels were significant (P<0.05) on juice content of fruits, arithmetic and geometric mean diameter, porosity of fruit and leaf water content. However, there was no significant difference for water branches. The maximum yield (12.03 kg tree-1) was occurred in the full irrigation level (ETc) and the lowest (4.95 kg tree- 1) was observed in the severe water stress treatment (0.2 ETc). Twenty percent reduction in applied water from full irrigation level caused 25.4 percent decrease in yield. The water content of leaves and branches was ranged between 38-50% for different irrigation levels. The overall conclusion of this study is that the subsurface drip irrigation system is a suitable method for irrigated olive trees in arid and semi arid region with gravel soil and the olive tree is perfect for green space.