Productive and vegetative tree responses were analyzed during 3 consecutive years in peach [Prunus persica (L.) Batsch cv. Sudanell] plots subjected to three regulated deficit irrigation (RDI) strategies plus a control irrigation treatment. A postharvest RDI treatment (RDI-P) was irrigated at 0.35 of control after harvest. A Stage II RDI treatment (RDI-SII) was irrigated at 0.5 of control during the lag phase of the fruit growth curve. The third treatment (RDI-SII-P) applied RDI during Stage II at 0.5 of control and postharvest at 0.35 of control. The control treatment, like RDI-P and RDI-SII-P when not receiving RDI, was irrigated at 100% of a water budget irrigation scheduling in 1994 and 1996, full crop years, and 80% of the budget in 1995, an off year with a very small crop. A carry-over effect of deficit irrigation was highly significant in all parameters measured during the third year of the experiment. The general effect of water stress during Stage II did not affect return bloom and fruit set, whereas water stress during postharvest apparently reduced both parameters. As a consequence, fruit counts and fruit load manifested marked differences between treatments, which were also correlated to changes in fruit size. The RDI-II, which had the highest fruit yield, also had the smallest fruit size, whereas RDI-P manifested the lowest yield and largest fruit size. Vegetative growth (shoot elongation and trunk cross sectional area) was significantly reduced during the first 2 years of the experiment in accordance with the amount of the irrigation reduction. However, in 1996 growth was strongly governed by fruit load. The use of RDI-SII-P represented an intermediate cropping effect between the opposite bearing behavior of RDI-SII and RDI-P, while not expecting distinctive fruit yield or size reductions and offering remarkable water savings of 22% of the control applied water.
Joan Girona, Mercè Mata, Amadeu Arbonès, Simó Alegre, Josep Rufat, and Jordi Marsal
Josep Rufat, Agustí J. Romero-Aroca, Amadeu Arbonés, Josep M. Villar, Juan F. Hermoso, and Miquel Pascual
This study describes the effects of mechanical harvesting and irrigation on quality in ‘Arbequina’ olive oil (Olea europaea L.). Irrigation treatments included a control, deficit irrigation (DI) during pit hardening, and subsurface deficit irrigation (SDI). Results showed that mechanical harvesting damaged the olives and reduced olive oil quality by increasing free fatty acids (FFAs) and peroxide value, and by decreasing fruitiness, stability, bitterness, and pungency. DI resulted in increased fruit dry weight and oil content, which could be explained by their reduced crop load (9.3% of crop reduction for DI and 23.9% for SDI). DI did not affect olive oil characteristics, whereas SDI increased stability, fruitiness, and bitterness, and decreased polyunsaturated fatty acid (PUFAs). In conclusion, mechanical harvesting tended to damage the fruit, resulting in lower quality olive oil, the DI strategy neither affected fruit nor olive oil characteristics, whereas the SDI strategy positively affected oil quality when greater water restrictions were applied.