The Impact of Foliar Application of Calcium Fertilizers on the Quality of Highbush Blueberry Fruits Belonging to the ‘Duke’ Cultivar

The studies were conducted in the period of 2010-2011, in the Laboratory of Orcharding at the West Pomeranian University of Technology in Szczecin, and related to the bushes of the highbush blueberry of the Duke cultivar. The authors examined the impact of foliar calcium fertlizers (Calcinit, Calcium chloride, Fruton Calcium Calcium, Folanx®Ca29 Lebosol Calcium Forte Calcium Forte) on the fruit size and firmness, their chemical composition, content of macronutrients in the foliage and fruits, and their colour. It was found that the applied fertlizers have varied impact on the examined attributes. The bushes sprayed with the Lebosol Calcium Forte and Calcinit preparations had big fruits with a high content of K and Mg, and dark foliage. The application of the Lebosol Calcium Forte fertilizer increased the content of polyphenols and vitamin C in the fruits. The smallest amounts of such compounds were determined in the fruits sprayed with the Calcinit fertilizer. The highest firmness and resistance to mechanical damage were achieved in the case of the fruits collected from the bushes sprayed with the foliar fertlizers containing calcium chloride, such as Fruton Calcium and Folanx Ca29. It was determined that the application of the calcium preparations resulted in the increase of the calcium content in the fruits and foliage. The highest amounts of this element were determined in the case of the plants sprayed with the Folanx Ca29 and Lebosol Calcium Forte preparations.