Nitrogen Management of Greenhouse Pepper Production: Agronomic, Nutritional, and Environmental Implications

摘要

Producers of horticultural products face new and growing standards regarding food quality and safety as well as environmental responsibility and sustainability. The objective of this research was to reduce environmental pollution by increasing nitrogen use efficiency (NUE) in vegetables without negatively affecting fruit yield or quality. Bell pepper was used as a case study for intensive vegetable cropping. Pepper cultivars with different vegetative vigor were drip-irrigated with solutions containing 9.2, 56.2, 102.3, and 158.5 mg.L-1 nitrogen (N). Fruit yield, quality, and nutritional value were measured. Nitrogen balance was determined by quantifying N in soil and in plant tissues. Maximum yields were found when peppers were irrigated with 56.2 mg.L-1 N. Nitrogen concentrations of 102.3 and 158.5 mg.L-1 N loaded 400 and 800 kg.ha(-1) N into the environment, respectively, whereas for the 56.2 mg.L-1 N concentration, N was almost completely taken up and used by the plants. Nitrogen treatments had no significant negative effect on pepper fruit physical or chemical quality parameters including sugar content and acidity. Reduced N application did not affect nutritional quality components of the pepper fruit such as beta-carotene and lycopene content or total antioxidant activity. The vigorous cultivar used N more efficiently. The results demonstrate how the environmental impact of intensive agriculture can be minimized without harming fruit yield or quality by reducing N application level and adopting cultivars with improved N use efficiency.