Bacillus-loaded biochar as a dual strategy for Fusarium wilt control and soil health improvement in Peanut cultivation

The combination of biocontrol agent and biochar presents an eco-friendly alternative for managing soilborne diseases, reducing the dependence on chemical fungicides. However, it remains unclear how biocontrol agent loaded biochar alleviates wilt disease and its interactions with soil microorganisms. This study investigated the effects of Bacillus subtilis BT-loaded biochar (BTBC) compared to the application of the biocontrol strain (BT) and biochar (BC) in controlling peanut wilt disease and its rhizosphere regulation mechanisms. The results showed that BTBC significantly increased the intensity of B.subtilis in the rhizosphere (by 2.7 times) and roots (by 65.3 times) compared to the disease control (FO). It also decreased the disease incidence of peanuts by 75 % and the abundance of Fusarium oxysporum in roots by 94.7 %, simultaneously enhancing the resistance against disturbance of the rhizosphere microbial community. BTBC significantly increased the content of soil organic matter and available potassium, and notably improved the dry weight of peanut pods. In conclusion, the application of B.subtilis loaded biochar not only boosted the colonization of B.subtilis in the environment and its efficacy against F.oxysporum-induced wilt disease, but also improved the soil nutrients and microbial community's resistance to disturbance. These findings provide new insights into managing and controlling the peanut wilt disease.