Crop yield response to water - Cra

season (Marsal, 2010). However, the realization of possible yield reductions in the next seasonafter a RDI postharvest treatment will depend on whether cherry thinning is being used tomaintain fruit size (Marsal, 2010). Nevertheless, if water stress during postharvest is maintainedabove -1.5 MPa in midday stem-water potential, large savings of up to 40 percent of the waterused in a fully irrigated control during postharvest can be achieved without noticeable negativeimpact on fruit yield and quality. The avoidance of water stress, more severe than a certain level(i.e. -1.5 MPa), implies that irrigation reduction must be adjusted with time and a fixed irrigationrate should only be maintained for a certain period to avoid surpassing such tree water statusthreshold. For this reason significant irrigation reductions during postharvest have to be appliedcautiously. Irrigation could also be reduced during postharvest at lower rates (i.e. 80 percentfull irrigation). The use of 80 percent full irrigation during postharvest produced water savingsup to 15 percent of annual applied water with no detrimental effects on fruit yield and quality(Table 1) (Marsal, 2009 and Marsal, 2010) although the research indicated that cherry qualityand yield responses to RDI are cultivar dependent. Therefore more research is needed beforereliable assessments can be made for each specific growing condition.Table 1Suggested Postharvest RDI strategies for different available water supply scenarios from 690 to430 mm. Weather data corresponds to the Ebro valley (Northeast Spain) and K c corresponds tothose presented in Figure 2 for high vigour growing conditions.Potential ET c Water req. RDI-Postharvest (580 mm) RDI-Postharvest (430 mm)(mm)(mm)Irrigationrate (%)(mm)Irrigationrate (%)(mm)March 15-30 9 10 100 10 100 10Apr. 1-15 24 26 100 26 100 26Apr. 16-30 34 31 100 31 100 31May 1-15 50 42 100 42 100 42May 16-31 49 40 100 40 100 40June 1-15 66 72 80 58 50 36June 16-30 80 88 80 70 50 44July 1-15 76 78 80 62 50 39July 16-31 81 89 80 71 50 44Aug. 1-15 70 77 80 62 50 39Aug. 16-31 68 75 80 60 65 49Sept. 1-15 38 42 80 34 50 21Sept. 16-30 23 25 80 20 50 12Oct. 1-15 11 0 80 0 50 0Oct. 16-31 7 0 80 0 50 0Nov. 1-15 5 0 80 0 50 0Total 690 696 587 434sweet CHERRY 455