The effect of foliar spray with N, ZN and B on the fruit set and cropping of Iranian local olive trees

This research was conducted on the Iranian local olive ''Olea europaea '' trees Zard cv. in a commercial olive plantation in west Iran where 25 years old olive trees were studied in respect of the effects of leave nutrition with urea, Boric acid and ZnSo4 with 0.5% concentration alone and in combination, one week prior to full bloom. The percentages of the initial and final fruit sets, the number of fruits at the time of harvest and 'shotberry' fruits percentage were examined. Urea spray of 0.5% concentration significantly increased initial fruit set while spraying with B and Zn caused significant increase of final fruit set and the number of fruits only during fruit harvest and generally the fruit drops number, as result of application of B and Zn spray, were decreased. It was also clearly observed that sole application of B spray or its combination with N significantly decreases shotberry fruits and the level of fruit abscission. Significant and positive. Correlation coefficients were found between the fruit B content, leave P and fruit set. Also there is significant negative correlation between fruit N content and percentage of shotberry fruits.