Effects of Preharvest Deficit Irrigation Treatments in Combination With Reduced Nitrogen Fertilization on Orchard Performance of Nectarine With Emphasis on Postharvest Diseases and Pruning Weights

Abstract

Fruit production should be adapted to future scenarios that are frequently associated with scarce resources, especially freshwater and fertilizers. New biologically-based fruit production strategies, i.e. taking into account tree growth and water status, are required to optimize irrigation and fertilization under abiotic stress conditions. It was hypothesized that a moderate abiotic stress, here deficit irrigation with or without nitrogen deficit, in the preharvest period, could decrease postharvest losses due to diseases and pruning weights due to reduced vegetative growth, without sacrificing the yield and fruit quality. This study was conducted over two years using the same trees of ‘Moncante’ nectarine cultivar grown in a commercial orchard. Trees were assigned to three treatments: (1) full irrigation at 80% estimated crop evapotranspiration (ETc), (2) deficit irrigation, i.e. at 75% of full irrigation, and (3) deficit irrigation and deficit nitrogen, i.e. at 75% of full irrigation and 75% of usual N-fertilization adopted by the grower in this commercial orchard. Deficit irrigation alone and in combination with deficit nitrogen reduced postharvest diseases and pruning weights without significant yield losses. Our results suggest that ETc-based approaches of reduced water irrigation may be a sustainable way to decrease phytosanitary inputs and workload in the orchard while maintaining the orchard performance.

Managing Crop Diseases Under Water Scarcity

“…Beyond woody crops, in Florida (USA) fresh market tomato production, severity of bacterial spot (Xanthomonas campestris) was not affected by deficit irrigation (70% and 85% ET versus 100% ET) (56); however, in this same study, early blight (Alternaria solani) was more severe under deficit irrigation (56). Generally, suppressive to neutral effects were hypothesized to be related to reduction in infectable plant tissue and suppression (or lack of an effect) on sporulation and infection under lower canopy humidity (5,6,56,84). In the unusual instance of increased disease severity under deficit irrigation, drought stress was postulated to compromise host resistance (56).…”

“…In California almond orchards, Teviotdale et al (84) found that reducing water inputs to near-stress levels using deficit irrigation (in reference to base ET) reduced the incidence of dead leaf clusters, amount of dead wood, and incidence of hull rot caused by Rhizopus stolonifer and Monilinia fructicola. In nectarine orchards in Turkey, Atay et al (5) found that deficit irrigation up to 75% of full ET (drought stress-inducing) either suppressed or did not influence fruit rot development associated with species of Monilinia, Rhizopus, and Botrytis (species names not provided). Beyond woody crops, in Florida (USA) fresh market tomato production, severity of bacterial spot (Xanthomonas campestris) was not affected by deficit irrigation (70% and 85% ET versus 100% ET) (56); however, in this same study, early blight (Alternaria solani) was more severe under deficit irrigation (56).…”