Abstract:To reveal the regulating effect of bioorganic fertilizer on peanut continuous cropping obstacle under intensive management system, a 5-year pot experiment was conducted with chemical fertilizers and bioorganic fertilizer (organic fertilizer inoculated with Bacillus pumilus WXX-2) applied under peanut continuous monoculture and peanut/maize rotation in order to explore the microbial mechanism in the rhizosphere of bioorganic fertilizer application to relieve the continuous cropping obstacle of peanut. Compared to rotated peanuts, pod yield of mono-cropped peanuts applied with chemical fertilizers significantly decreased; Compared with chemical fertilization of mono-cropped peanuts, persistent bioorganic fertilization significantly mitigated the severity of yield reduction, with pod yield increased by 27% on the fifth year of fertilization. Compared to mono-cropped peanuts applied with chemical fertilizers, persistent application of bioorganic fertilizer significantly increased rhizosphere bacterial diversity and richness, with no significant difference with those of rotated peanuts. Persistent application of bioorganic fertilizer significantly increased the relative abundances of Proteobacteria and Bacteroides, and decreased that of Firmicutes in peanut rhizosphere. At the genus level, the relative abundances of Rhizobium, Mesorhizobium and Bradyrhizobium, which are important plant growth-promoting rhizobacteria, increased by 295%, 89% and 40%, respectively, and those of Leifsonia and Burkholderia decreased by 67% and 47% under five-year bioorganic fertilization. Redundancy analysis further revealed that the increase of soil pH and organic matter may be responsible for the optimization of rhizosphere bacterial community structure. This indicated that persistent application of bioorganic fertilizer can improve physicochemical properties of red soil, optimize the microbial structure and enhance peanut resistance to diseases in the rhizosphere subsequently, thus can stably promote crop yield.