Effects of various nitrogen fertilizers and the Extrasol biopreparation on the quality of garden strawberry (Fragaria×ananassa Duch.) at fertigation with drip irrigation on soddy podzolic soils

Current approaches to land use and agricultural production are increasingly aimed at achieving high productivity through the use of crop rotation, siderites, integrated plant protection, minimized soil cultivation, microbiological fertilizers, and biological preparations. Modern microbiological preparations enhance the uptake of nitrogen and ash elements by plants, improving the rhizosphere of plants and the quality of strawberry fruit. Aim. To establish the effect of Extrasol applied using drip irrigation and various forms of mineral nitrogen fertilizers on the chemical composition of leaves and fruit of garden strawberry.Materials and methods. Garden strawberry plants of the Rusich and Troitskaya cultivars were treated with Extrasol and mineral fertilizers. Experiments were carried out in 2017–2020 at open-ground plots of the Federal Horticultural Center for Breeding, Agrotechnology and Nursery (Moscow Oblast). The experimental plots were characterized by soddy podzolic soils of medium-loam granulometric composition. Plant samples were analyzed using conventional methods. The experimental scheme consisted in the application of various nitrogen fertilizers (ammonium nitrate, urea, and ammonium sulfate) either in combination (2 mL/L of the working solution) or without Extrasol. Conclusions. In strawberry cv. Rusich, the use of ammonium nitrate increased the calcium content in plant leaves and decreased its content in fruit, which negatively affected the crop quality. Mineral fertilizers applied in combination with Extrasol increased the nitrogen content in leaves and fruit. The combined use of the amide form of nitrogen (urea) and Extrasol adversely affected the level of nitrates in cv. Troitskaya fruit. The use of fertigation and Extrasol reduced the amount of soluble dry substances in strawberry fruit.