Abstract
The study was done in the 2022 growing season on 16-year-old Arbequina olive trees cultivated at 6×6 m apart in clay sandy loam soil under a drip irrigation system in a private orchard located at Zakho region, Duhok governorate, Kurdistan region, Iraq, to study the influence of different types of fertilizers on the growth and productivity of olive trees (Olea europaea L.) cv. Arbequina. The experiment consists of twenty-seven treatments (three levels of soil application of chicken manure 0,5, 10 kg tree-1, foliar application of three conc. of seaweed extract (Sea force) 0,10,20 ml L-1 and soil application of three levels of mineral fertilizer Blaukorn NPK (12:12:16) at level (0, 150, and 200g tree-1), mineral fertilizer was applied three times per season: First: at vegetative growth stage. Second: at full bloom. Third: after setting of fruits. Results indicate that soil application of chicken manure, especially at 10 kg tree-1, and foliar spraying of Sea force at 20 ml L-1 significantly increased all studied characters (average leaf area, total chlorophyll content, number of flowers/inflorescences, fruit set %, fruit length, fruit width, fruit weight, total yield per tree, fruit total soluble solids (TSS%), Percentage of oil). Soil application of Blaukorn, especially at 200 g tree-1, significantly increased (average leaf area, fruits length, width and weight, and TSS). The binary and triple interactions of the study treatments on all the traits under investigation also showed a significant increase, particularly for the high levels of the study factors.
