EFFECTS OF DIFFERENT LEVELS OF NITROGEN ON PRODUCTION AND QUALITY OF STRAWBERRIES FROM FRESH "PLUG PLANTS"

Nitrogen is an essential element, not only for its influence on the vegetative-productive activity of the plants but also on fruit quality (color, shelf life, etc.). To achieve high production and quality standards, reducing environment impact, the S.Ag.A Department of Palermo carried out some researches to identify the most suitable fertilization to maximize the productive potential of fresh plug plants of two cultivars of strawberry widespread in the Sicilian area, ‘Sabrosa®Candonga’ and ‘Nora’, reducing Nitrogen inputs. The experimental design adopted was a splitplot, in which the main plot was the different doses of nitrogen, 120, 170, 220, 270, 320 kg/ha and the secondary one the cultivar. This research showed a rather wide variability of results, dependent on levels available for plants and doses distributed between the cultures. The seasonal pattern of production showed how the plot fertilized with 270 kg/ha has always achieved the highest harvest, but it's not significant for statistic analysis, in the early productive period (January-March) with the thesis treated with lower doses (120 and 170 kg/ha). The lowest doses (120 and 170 kg/ha) provided the firmest fruits, 735 g, with an high content in total soluble solids content, 7.3°Brix, and highest vitamin C, 53 mg/100 g of f.w., and a very bright orange-red color. It has been noted that the two cultivars fertilized with medium and low doses produced larger fruits, with a high soluble solids and vitamin C content. In conclusion, in greenhouses cultivation, the application of low doses of nitrogen achieves the same production, as higher doses, and high fruit quality, reducing environmental and production costs.