Biochar microbial fertilizer enhances flue-cured tobacco quality and yield by regulating rhizosphere soil nutrients and microbial community

Abstract Objective To provide a scientific foundation for the efficient use of biochar microbial fertilizer to improve both quality and production, this study will look at the impact of applying biochar microbial fertilizer at different fertility levels on the soil environment and flue-cured tobacco quality. Methods We investigated the impact of biochar microbial fertilizer on tobacco agronomic indicators, flue-cured tobacco yield and quality, rhizosphere soil physical and chemical properties, and diversity of microbial communities. Results (1) Fertilization treatment significantly increased tobacco stem circumference, leaf number, and size during the tobacco maturation period, optimized economic traits, and improved the physical properties of tobacco leaves. In addition, fertilization can increase total alkaloid, potassium, and aromatic substance levels in flue-cured tobacco and improve its overall quality. (2) After applying biochar microbial fertilizer, the amount of readily available nutrients in the soil around tobacco roots went way up, and the soil structure got better. (3) Biochar microbial fertilizer changed the rhizosphere soil microbial composition and diversity. (4) Pearson's correlation analysis showed that there was a significant correlation between key rhizosphere soil microorganisms and the chemical constituents of flue-cured tobacco, which showed characteristic positive/negative correlations. Conclusion Biochar microbial fertilizer improves tobacco agronomic indicators, cured tobacco leaf quality, and yield. Biochar microbial fertilizer changed the rhizosphere soil's microbial composition and diversity. The diversity and composition of rhizosphere soil microorganisms may also affect the soil's chemical composition.