Yield and water productivity of peach trees under continuous deficit irrigation and high evaporative demand

Long-term effects of deficit irrigation on yield and water productivity of peach trees (Prunus persica L., cv. Carnival) grown in a semi-arid climate in northern Tunisia (36°41'N, 10°15'E) were investigated. Continuous deficit irrigation (Di I-II-III) was compared with the grower's irrigation programme (Control). The effects of Di I-II-III on yield and fruit quality were analysed. The benefit of deficit irrigation strategy in terms of water saving and agricultural water productivity (Wₚ) were estimated. Different relationships were investigated between yield, fruit quality, and Wₚ, and irrigation and total water supply. In reference to the high water needs of late cultivar Carnival for irrigation, Di I-II-III led to an important water saving (33%) with a yield reduction of 14%. Yield and fruit quality seemed to be related to watering regimes. Fruit dry matter (DM) decreased linearly with irrigation water supply for both Control and Di I-II-III. Unlike yield, Di I-II-III improved the dry weight of fruit. Consequently, Wₚ was enhanced to reach a mean value of 0.62 kg DM m⁻ ³ in contrast to 0.54 kg DM m⁻ ³ for the Control. Continuous deficit irrigation is a valuable tool for improving Wₚ in peach orchards, achieving significant water saving and maintaining sustainable production levels