Long-term response of ‘Clementina de Nules’ citrus trees to summer regulated deficit irrigation
Regulated deficit irrigation (RDI) has been assessed in a wide number of fruit crops. However, few are the studies dealing with long-term RDI strategies. In this work, we assessed the response of ‘Clementinade Nules’ citrus trees to summer RDI treatments [RDI-1, irrigated at 50% of crop evapotranspiration (ETc)and RDI-2, irrigated at 35% ETc] during six consecutive seasons (2007–2012). Although water restrictions were applied according to reductions over ETc, threshold values of stem water potential (−1.3 to −1.5 MPain the RDI-1 treatment and −1.5 to −1.7 MPa in the RDI-2) were also considered for scheduling deficitirrigation. Results showed that the water stress imposed in the RDI-2 treatment had a noticeable impacton fresh fruit weight, reducing yield and economic return over the six years and more so during the first two years in comparison to a control treatment irrigated at 100% ETc during the whole season. The RDI-1strategy had a lower impact than the RDI-2 treatment on the fresh fruit weight and did not significantly reduce yield or the economic return over the six seasons.
