of fruit trees has highlighted the potential of using various forms of deficit irrigation in the water management of orchard and vineyards (Fereres et al., 2003).
We define regulated deficit irrigation (RDI) as a regime that purposely stresses the trees or vines at specific developmental stages of the crop such that there is little, if any, negative impact on the yield of marketable product and/or profits. The water stress is normally imposed at stages of the season when reproductive growth is relatively low. The water stress results in lower tree water status, partial stomatal closure, which reduces ET (Fig. 1). The objective of RDI is to maintain or increase farm profits while reducing the consumptive use of water.