Sugar beet (Beta vulgaris L.) performance is strongly shaped by fertilization-driven interactions between rhizospheric microbiota and leaf anatomical traits. This study investigated the effects of NPK mineral fertilization and RIES treatment on microbial community structure and stomatal characteristics under field conditions. The experiment followed a randomized block design, including an unfertilized control and five NPK variants differing in nutrient ratios, applied as seed treatment, foliar treatment, or their combination. Microbiological analyses quantified total microorganisms, ammonifiers, Azotobacter, oligotrophic bacteria, and fungi, while anatomical assessments targeted stomatal density and size on both leaf epidermises. NPK fertilization substantially increased microbial biomass, particularly stimulating ammonifiers and fungi, while sharply reducing oligotrophic bacteria. Azotobacter populations were enhanced under moderate fertilization but declined at high nitrogen levels. High P and K supply decreased stomatal density relative to the control, whereas elevated nitrogen exerted a compensatory effect. Stomatal length remained largely unchanged across treatments, while stomatal width increased under balanced nutrient input. Overall, the results indicate that optimizing NPK ratios supports both microbial functionality and leaf-level anatomical traits associated with physiological efficiency. These findings highlight the importance of integrating nutrient management with biological processes to promote sustainable intensification, enhancing both crop productivity and agroecosystem resilience under changing environmental conditions.

NPK fertilization, RIES treatment, sugar beet, rhizospheric microbiota, stomatal characteristics

agronomy

Presentation: poster