Plant–Soil Feedback In Camellia Oleifera And Mixed Gardenia Jasminoides Ellis–Camellia Oleifera Stands Determined By Soil Bacterial Community Analysis

Abstract

Purpose: Little is known regarding the combined impact of plant and soil traits on the soil bacterial community. Herein, we assessed physical and chemical properties along with bacterial community structure in soils sampled at different depths (0–20 cm, 20–40 cm, and 40–60 cm) and slope positions (peak, hillside, and bottom), in Camellia oleifera monoculture and mixed Gardenia jasminoides–Camellia oleifera stands. Methods: Soil physicochemical characteristics were determined using standard methods. The composition of soil bacterial communities was evaluated using high-throughput sequencing of the 16S rRNA gene. Results: Soil organic carbon, humus, and total organic contents were higher in G. jasminoides + C. oleifera low-yielding forest than in other stands, however, the NH4+-N levels were significantly lower than that in monoculture. The slope position did not greatly influence soil physical and chemical properties. The dominant bacteria were Proteobacteria, Chloroflexi, Acidobacteria, and Actinobacteria. The alpha and beta diversity and abundance of soil bacterial community were higher in intercropping systems than in monoculture systems. Potassium and nitrogen levels and pH significantly affected the soil microbial community composition. Correlation analysis revealed that alkaline hydrolysable nitrogen and pH were significantly correlated with the input of plant-associated organic matter and dynamic changes of keystone taxa.Conclusion: G. jasminoides improved the physicochemical characteristics of C. oleifera low-yielding soil and greatly affected the soil bacterial community, further improving the soil microecological environment. Therefore, this specific intercropping system is an effective strategy for improving soil health.