FERTIGATION MANAGEMENT TO MAXIMIZE OLEUROPINE CONTENT IN OLIVE LEAVES

Abstract

This study was conducted for three successive seasons (2015/2016/2017) onChemlali olive trees 15 year’s old at a private orchard, located on the 32 km Cairo–Alexandria desert road. The main aim of the present research is to study the effect of irrigation system (dripper and bubbler); deficit irrigation regimes ”DIR” (75 % and 50 % ETc.) and 4 additional doses of urea by two rates of dose (200 gm and 400 gm), injected throughout irrigation system , with a rate of (1 kg./100 l), during March, on vegetative growth “ number of new shoots; shoot length; shoot diameter; number of leaves per shoot and leaf area”; fruit yield; alternative bearing index and Oleuropein concentration in the olive leaves. The following treatments were applied: T1: control (100% ETc. by drip with recommended fertilization rate); T2 (50% of ETc. by drip + 0.8 kg urea/tree); T3 (50% of ETc. by drip + 1.6 kg urea/tree); T4 (75% of ETc. by drip + 0.8 kg urea/tree); T5 (75 of ETc. by drip+1.6 kg urea/tree) T6 (50 % of ETc. by bubbler + 0.8 kg urea/tree); T7 (50% of ETc. by bubbler + 1.6 kg urea/tree); T8 (75% of ETc. by bubbler + 0.8 kg urea/tree) and T9 (75% of ETc. by bubbler+1.6 kg urea/tree). The results indicated that, all parameters of the vegetative growth and fruit yield increased by using bubbler 100l/h and applying the proposed DIR with additional doses of urea. The highest value of alternative bearing index was 0.256 recorded with control treatment (T1). Meanwhile the lowest alternate bearing index was 0.131 recorded with (T9). Oleuropein concentration in the olive leaves increased with all tested treatments compared with (T1), the lowest value of Oleuropein content was 58 (mg/100gm) obtained under the control treatment (T1). The highest values of Oleuropein content were 316.59 (mg/100gm) obtained with (T9). Thus, applying DIR 75 % ETc. with 4 additional doses of urea (400 gm for each) during March by using bubbler system, with saving 25% of irrigation water, will improve vegetative growth and reduce the severity of alternative bearing, as well as increase the Oleuropein concentration in the olive leaves.