The Combination of Biochar and Biological Agent Reduced the Relative Abundance of Pathogenic Bacteria in the Rhizosphere Soil of .

In the continuous cropping of , the pathogenic fungi in the rhizosphere soil increased and infected the roots of , resulting in a decrease in yield. This is an urgent problem that needs to be solved in order to effectively overcome the obstacles associated with the continuous cropping of . Previous studies have shown that inhibits pathogenic fungi in the rhizosphere of , but the inhibitory effect was not stable. Therefore, we hope to introduce biochar to help colonize in soil. In the experiment, fields planted with for 5 years were renovated, and biochar was mixed in at the same time. The applied amount of biochar was set to four levels (B0, 10 kg·hm; B1, 80 kg·hm; B2, 110 kg·hm; B3, 140 kg·hm), and biological agent was set to three levels (C1, 10 kg·hm; C2, 15 kg·hm; C3, 25 kg·hm). The full combination experiment and a blank control group (CK) were used. The experimental results show that the overall decreased by 0.86%65.68% at the phylum level. increased by -73.81%138.47%, and increased by -51.27%403.20%. At the genus level, increased by -10.29%855.44%, decreased by 35.02%86.79%, and increased by -93.60%680.62%. mainly causes acute bacterial wilt root rot, while mainly causes yellow rot. Under different treatments, the Shannon index increased by -6.77%62.18%, the Chao1 index increased by -12.07%95.77%, the Simpson index increased by -7.31%14.98%, and the ACE index increased by -11.75%96.12%. The good_coverage indices were all above 0.99. The results of a random forest analysis indicated that , , and were the top three most important species in the soil, with MeanDecreaseGini values of 2.70, 2.50, and 2.45, respectively. , the primary pathogen of , ranked fifth, and its MeanDecreaseGini value was 2.28. The experimental results showed that the B2C2 treatment had the best inhibitory effect on , and the relative abundance of in rhizosphere soil decreased by 86.79% under B2C2 treatment; the B1C2 treatment had the best inhibitory effect on , and the relative abundance of in the rhizosphere soil decreased by 93.60% under B1C2 treatment. Therefore, if we want to improve the soil with acute Ralstonia solanacearum root rot, we should use the B2C2 treatment to improve the soil environment; if we want to improve the soil with yellow rot disease, we should use the B1C2 treatment to improve the soil environment.