Effect of Foliar Fertilizer Applications on Yield and Quality of Edible Grapevine Leaves (Vitis vinifera L.)

Abstract

Objective: This study aimed to determine the effects of foliar fertilizer applications (FFA) on edible leaf yield and physicochemical properties of Narince grapevines grown for edible leaf production.Materials and Methods: The research was conducted on Narince grapevines grafted onto 110R rootstock. Six different foliar fertilizers containing varying concentrations of N, P, Mn, Zn, Fe, B, and Mo were applied twice: once when shoots reached 15 cm and again at the beginning of flowering. Only distilled water was used in the control application. Leaf yield, leaf weight, leaf area, soluble solids (SSS), total acidity, pH, and leaf color parameters (L, a, b*) were determined in leaves harvested at five different periods.Results: Foliar fertilizer applications resulted in statistically significant differences in leaf yield, leaf weight, average leaf area, and the L, a, and b* values of the leaf color parameters. The highest total leaf yield was obtained from FFA-5 (1652.6 g/vine) and YGU-6 (1627.0 g/vine) applications. FFA-5 application resulted in approximately a 17% yield increase compared to the control application. Foliar fertilizers positively affected vegetative growth parameters such as one-year-old branch diameter and height.Conclusion: In vineyards where food leaf cultivation is carried out, it has been determined that foliar fertilization, especially with FFA-5 (containing 10% Organic Matter, 5% Total N, 40% P₂O₅ and Zn) and FFA-6 (containing 9% Total N, 5% P₂O₅, 40% K₂O, B, Fe, Mn and Zn), when applied at the appropriate dose and timing (before and at the beginning of flowering), promotes yield and vegetative growth and does not negatively affect quality parameters. Producers in similar ecological conditions are advised to pay attention to the application time and application-harvest interval (14 days after the first application, 9 days after the second application).