• N fertilizer altered bacterial community compositions by changing soil nutrients. • Bacterial ammonia oxidation became predominated with the increasing N rate. • Excessive N input caused the information of a more complex microbial network. • Intensified microbial competition by excessive N was due to negative link increase. Nitrogen (N) fertilization drives the structure and function of soil microbial communities, which are crucial for regulating soil biogeochemical cycling and maintaining ecosystem stability. Despite the N fertilizer eff...
