The Controlled-Release Nitrogen Fertilizer Driving the Symbiosis of Microbial Communities to Improve Wheat Productivity and Soil Fertility

Controlled-release nitrogen (CRN) fertilizers gradually release N in synchronization with root nutrient absorption, increasing wheat productivity and soil fertility. The role of the soil microbial community in wheat productivity and soil fertility, on the other hand, is unknown. Amplicon sequencing and a co-occurrence network were used in this study to investigate the role of microbial symbiosis in controlling wheat productivity and soil fertility in a 12-year (2008-2019) calcareous soil field experiment. Furthermore, the effects of various fertilization models were compared. The soil microbial community was divided into three closely coexisting symbiotic modules (Modules #1, 2, and 3). Module #1 and #2 were dominated by bacteria, while Module #3e was dominated by fungi. Modules #1 and #3 had higher network transmissibility (closeness centrality) and stability (degree) than Module #2, and they had a significant positive correlation with wheat productivity and soil fertility. Then, using random forests analysis, we examined the relationship between the module microorganism and wheat productivity and soil fertility. Module #1 microorganisms contributed more to wheat productivity and soil fertility than Module #3 microorganisms, and the microorganisms with significant relationships had a more complex composition (P < 0.05), primarily composed of Actinobacteria, Chloroflexi, Gemmatimonadetes, and Proteobacteria. Module #3, on the other hand, was primarily composed of Ascomycota. Finally, according to the structural equation model, CRN fertilizers could significantly improve wheat productivity and soil fertility when compared to soluble N (SN) fertilizers by increasing the diversity of the symbiotic module. In conclusion, our study discovered that Modules #1 and 3 are closely related to wheat productivity and soil fertility. The composition of module microorganisms, as well as the role of CRN fertilizer in symbiotic modules, were also investigated.