Slow-release nitrogen fertilizer promotes the bacterial community to drive soil multifunctionality.

The application of slow-release nitrogen fertilizer can gradually modify the soil microbiome, and its influence on the association between microbial diversity and soil multifunctionality remains controversial. In this research, the spatial variances of soil environmental factors, soil multifunctionality, and their correlations with bacterial and fungal communities under five nitrogen application rates were analyzed, and the key factors influencing microbial dominant species and community structure at different spatial locations were determined by the application rate of slow-release nitrogen fertilizer, and the driving factors and dominant species of soil multifunctionality were identified. The findings revealed that, in contrast to the control group, a moderate application of slow-release nitrogen fertilizer enhanced soil multifunctionality and ameliorated the resilience of microbial diversity loss at diverse spatial locations resulting from irrational nitrogen fertilizer application, and the resilience of the fungal community to disturbances caused by fertilization was lower than that of the bacterial community. Bacterial diversity exhibited a significant correlation with soil multifunctionality, and the soil multifunctionality intensity under the N16 (240kg/ha) treatment increased by 159.01% compared with the control. The main bacterial dominant communities (including members of Proteobacteria, Actinobacteria, and Acidobacteria) and the fungal dominant community Ascomycota affected soil multifunctionality through the application of slow-release nitrogen fertilizer. Random forest analysis and structural equation modeling demonstrated that bacterial community diversity (particularly in the bulk soil and rhizosphere), community composition, and soil nitrogen form were the primary driving factors of soil multifunctionality. The results of this study indicated that microbial niche alterations induced by the application of slow-release nitrogen fertilizer exerted a positive effect on soil multifunctionality.