FEATURES OF PRODUCTIVITY FORMATION IN FODDER BEET DEPENDING ON VARIETAL CHARACTERISTICS AND MINERAL NUTRITION LEVEL

Abstract

The article presents the results of long-term field experiments (2020–2024) aimed at investigating the influence of different rates and ratios of mineral fertilizers on the dynamics of root and leaf biomass formation in different fodder beet cultivars under the conditions of the Western Forest-Steppe of Ukraine. The study demonstrated that the application of mineral fertilizers significantly stimulated plant growth and development, promoting more intensive accumulation of aboveground and underground biomass throughout the growing season. The highest root and leaf biomass values were obtained under the fertilizer treatments N₁₅₀P₇₅K₂₂₅ and N₂₂₅P₇₅K₁₅₀. At harvest, the average root weight under the N₁₅₀P₇₅K₂₂₅ treatment reached 1053.1 g for the Sonet cultivar, 1131.1 g for Olzhych, and 1176.2 g for Starmon, exceeding the control by 20.5–27.1%. The most intensive development of the leaf apparatus was observed during the first decade of August, followed by an active translocation of assimilates from the leaves to the roots. Cultivar characteristics had a significant effect on biomass accumulation intensity. The Starmon cultivar exhibited the highest productivity, outperforming the Sonet and Olzhych cultivars in both root and leaf biomass throughout the entire growing season. Balanced mineral nutrition, particularly with increased potassium application, was found to prolong the functional activity of the leaf apparatus, improve assimilate translocation, and enhance root growth. Correlation and regression analysis confirmed a strong positive relationship between leaf biomass and root weight (r = 0.881; R² = 0.776). An increase of 1 g in leaf biomass resulted in an average increase of 1.24 g in root weight, indicating the decisive role of assimilatory apparatus development in determining crop productivity. The obtained results confirm the effectiveness of optimizing mineral nutrition of fodder beet through the application of balanced fertilizer rates with an increased potassium content. The fertilizer treatments N₁₅₀P₇₅K₂₂₅ and N₂₂₅P₇₅K₁₅₀ proved to be the most effective, ensuring the best plant growth, maximum biomass accumulation, and the highest realization of the crop’s productive potential. The Starmon cultivar exhibited the most pronounced response to improved mineral nutrition, forming the highest biometric parameters and root weight.