干旱区生态环境知识资源中心

Water scarcity in the arid zone appears as one of the main factors limiting agricultural development. For this reason it is necessary to reduce water use for irrigation and thereby increase crop water use efficiency. An experiment with different irrigation strategies (partial root zone drying and regulated deficit irrigation) was initiated to study these effects on intrinsic and extrinsic water use efficiencies of olive trees under the semi arid climate of Tunisia. The experiment was done in three consecutive years in a drip irrigated orchard of 'Chetoui' the most important cultivar of north of Tunisia located in the plain of Mornag. Five irrigation treatments were applied: NI (non irrigated), PRD100 and PRD50 (Respectively 100% and 50% of dose on one side alternating the wetted and dried sides of the root system every ten days), FI (control) and DI (irrigation with 50% of dose on two sides). Results showed that midday stem water potential was strongly decreased in stressed treatments accompanied by an improvement of the water use efficiency. Biochemical analyses showed differences between treatments.