Abstract <p>The purpose of this research is to study the effect of fertilizer rates on the yield of the main and secondary products and technological properties of root crops of domestic sugar beet hybrids in the zone of unstable moistening of the Central Black Earth Region. The work was carried out on leached low-humus medium-thick heavy loamy chernozem in Voronezh oblast in 2022–2024. The conditions were excessively humid in 2022, moderately humid in 2023, and arid in 2024. The scheme of the experiment included the following variants: hybrids (factor A) RMS 120, RMS 121, and RMS 127; fertilizer systems (factor B) without fertilizers (control), variant I (N₄₅P₄₅K₄₅ for sugar beet and 25 t/ha of manure for black fallow), variant II (N₉₀P₉₀K₉₀ and manure 25 t/ha), variant III (N₁₃₅P₁₃₅K₁₃₅ and manure 25 t/ha), variant IV (N₁₂₀P₁₂₀K₁₂₀ and manure 50 t/ha), and variant V (N₁₉₀P₁₉₀K₁₉₀). The RMS 127 hybrid was characterized by the highest yield of root crops in the experiment (49.6–50.8 t/ha) and the highest proportion of root crops in the total biomass (68.6–73.1%). Fertilizers exerted the greatest effect on the productivity of hybrid RMS 120 (+36.3–71.3% of the control) and on the share of root crops in the yield of RMS 121 (+4.0–9.7%). The sugar content did not change in the RMS 120 hybrid, when fertilizers were applied, but decreased in RMS 127 and especially in RMS 121. The sugar yield at the plant was the highest in the experiment, and the MB factor was the lowest in the RMS 120 hybrid, when using moderate fertilizer rates (systems I–III), and in RMS 121 in case of high fertilizer rates (systems IV and V). Root crops of RMS 121 were characterized by the maximal sugar extraction coefficient and the minimal sugar losses in molasses. The refined sugar production was the greatest for hybrids RMS 127 and RMS 120 (with high NPK saturation). We recorded the best productivity and yield of refined sugar for crops of RMS 127 with the use of II–IV fertilizer systems and for RMS 120 in variants II and III.</p>