Long-term productivity of early season peach trees under different irrigation methods and postharvest deficit irrigation

Deficit irrigation can be used as a potential means of dealing with lack of irrigation water, however, the long-term impact of deficit irrigation on productivity is not fully understood. A 10-year long field study was carried out to compare effects of furrow, drip, and micro sprinkler irrigation under either full irrigation or postharvest deficit irrigation treatments on peach tree health and fruit yield and quality. In the first three years of the experiment, trees under full irrigation grew faster which led to larger trunks than trees under deficit irrigation. At the end of the study, tree canopy size showed no difference among different methods of irrigation or between full and deficit irrigation. Deficit irrigation of up to 40% water savings did not lead to significant yield losses for 8-9 years. Deficit irrigation also did not cause a significant reduction in fruit quality except for an increase in percentage of double fruits, but the worst year case was still less than 1.5%. Fruit color showed lower lightness in furrow full irrigation than in furrow deficit treatment, but no difference was found in deficit drip or micro sprinkler treatment. Also, no difference was found for fruit firmness, total soluble solids, pH, malic acid, or total phenolics between the respective full and deficit irrigation treatments. The study demonstrated the feasibility of applying continued postharvest deficit irrigation for up to10 years for peach production which resulted in significant water savings during the summer peak water use period.