The applicability of some plant-based moni̇tori̇ng techniques in irrigation time planning in olive trees under deficit irrigation

This study was carried out in the olive trees (cv Memecik) in 2014 and 2015 in the Ministry of Agriculture and Forestry, Bornova Olive Research Institute. In this study, the changes in crop water stress index (CWSI), stem water potential (ΨS) and stoma conductivity (gs) in olive trees under different deficit irrigation strategies were observed and their behavior under stress conditions and the relationship between them were observed. In addition, different reactions of trees under different stress conditions were analyzed by measuring some fruit properties such as ripeness index, meat/seed ratio, and moisture and oil ratio. The total amount of irrigation water applied to the subjects varied between 78 mm and 661 mm. Also, evapotranspiration values ranged between 197 mm and 740 mm. According to the data obtained from the study, a statistically significant difference was found between the subjects in physiological parameters. On the other hand, no significant difference was found between the subjects in terms of fruit characteristics. When some physiological parameters were compared, it was observed that there was an important relationship between them. R2, in this case, refers to between 0.30 and 0.68. When the water supply is limited considering the yield results that obtained from the study, irrigation is recommended 3 times, taking into account 50% of the reduced moisture at the soil depth of 0 - 90 cm during the hardening, fruit growth and oil accumulation stages. On the other hand some physiological measurements such as crop water stress index (CWSI), stem water potential (ΨS) and stoma conductivity (gs) can be used in the formulation of the irrigation program for the cultivars. In terms of programming of irrigation time, 2.80 MPa for stem water potential (ΨS), 348 mmol m-2s-1 for stoma conductivity (gs) and 0.18 for crop water stress index (CWSI) can be taken as a threshold value.