Enhancing sugar beet yield and soil microbial activity under water-limited conditions through mycorrhizal and bacterial inoculations

Aim of this study is to investigate the effects of mycorrhizal and bacterial inoculations on sugar beet yield and soil microbial activity under varying water stress conditions. The field experiment was conducted over two successive years with three different irrigation levels: 33% (I1), 66% (I2), and 100% (I3). Mycorrhiza (Mikostar BTH-100) containing Glomus intraradices, Glomus mosseae, Glomus fasciculatum, and Glomus etunicatum, along with Bradyrhizobium japonicum bacteria, were applied to seeds during planting. Results showed that both applications significantly improved sugar beet yield and soil microbial activity compared to the control treatment. Mycorrhiza was particularly effective under full irrigation (I3), while bacterial inoculations showed stronger effects under moderate and low irrigation levels (I2 and I1, respectively). The highest yield (10130 kg/da) was observed under full irrigation with mycorrhiza treatment, while the lowest yield (3917.33 kg/da) was recorded in the control group under low irrigation. Soil microbial analyses revealed significant enhancements in CO₂ respiration, dehydrogenase activity (DHA), and microbial biomass carbon (MBC) in treated soils. These findings highlight the potential of mycorrhiza and bacteria to enhance plant performance and soil health under water-limited conditions, contributing to sustainable agricultural practices.