The mechanism of microbial community succession and microbial co-occurrence network in soil with compost application

The application of organic and chemical fertilizer into soil can regulate microbial communities. However, the response mechanism of microbial communities in soil to compost and chemical fertilizer application remain unclear. In this study, compost made of tobacco leaves individually and combined with chemical fertilizer was applied, respectively, to investigate their effect on soil microorganisms during the pot-culture process. High-throughput sequence, neutral community model and null model were employed to clarify how soil microbial community respond to the application of compost and chemical fertilizer. Furthermore, random forest model was applied to predict the relationships between the plant agronomical traits and the soil microorganism during the pot-culture process. The results demonstrated that the simultaneous application of compost and chemical fertilizer increased significantly the richness and diversity of the microorganisms in soil (p < 0.05), groups C and D led to a significant reduction in the number of nodes and edges in the microbial network (77.78 %-96.57 %). The dominant bacteria in the application of 50 g fertilizer accounted for the highest proportion (40 %) and organic matter was the main factors driving the change in bacterial communities. Compared to the tilled soil, the microbial communities of the soil with the simultaneous application of compost and chemical fertilizer were more susceptible to stochastic processes, and soil microorganisms had less influence on the growth of crops during pot-culture. In conclusion, the simultaneous application of compost and fertilizer altered the ecological functions of soil microbial communities, leading to an enhanced stochastic process of community formation.