Restoration of continuous cropping obstacles by microbial inoculants and mineral amendment in flue-cured tobacco

Abstract

Continuous cropping obstacles (CCOs) impair soil health and reduce crop yields, posing a significant challenge to agricultural sustainability. Tobacco is a vital economic crop worldwide. For shortage of arable land, tobacco suffers economic losses attributed to CCOs. To address tobacco CCOs, we conducted a 2-year field experiment utilizing microbial inoculants coupled with a mineral soil amendment (tobermorite). Compared to the control, the combined application of microbial inoculants (Bacillus velezensis K01 and Streptomyces xylanolyticus B75) with tobermorite significantly increased yield by 15.8% and economic value by 32.9%; reduced the disease index by 73.8% of black root rot caused by Fusarium spp.; and enhanced the absorption of mineral nutrients, increasing the leaf contents of boron (B), iron (Fe), and magnesium (Mg) by 45.0%, 65.7%, and 40.1%, respectively. Microbial inoculants and mineral soil amendment modulated the soil bacterial and fungal community structures, increasing bacterial and fungal richness, reducing the abundance of pathogens such as Fusarium, enriching beneficial native bacterial genera such as Pseudomonas, and increasing the number of nodes and edges in the fungal network. Path analysis revealed that fungal community abundance was a critical positive driver of flue-cured tobacco yield.