Rhizobacteria shaped by long-term fertilization and wheat nutritional requirements improve grain yield and soil multifunctionality

The microbial communities shaped by agricultural practices and plant nutritional requirements are critical for crop adaptability and productivity. Therefore, elucidating how soil microbial communities respond to these factors under different nutrient conditions is important for crop growth, soil multifunctionality (SMF) enhancement, and management optimization for sustainable agriculture development. We investigated the effects of soil properties, enzyme activities, microbial composition and functional genes on wheat grain yield and SMF with a 9-year fertilization and irrigation experiment. Results showed that wheat grain yield in NPK fertilizers (C) and manure (M) was 112.1 %-204.1 % and 83.4 %-185.8 % higher than that in no fertilizer (CK), respectively. M had higher microbial diversity, network complexity, enzyme activity and SMF than C and CK. Furthermore, fertilization regimes interacted with wheat nutritional requirements to enriched key bacterial species (e.g., Streptomycetaceae, Rhizobiaceae, Xanthomonadaceae, and Sphingobacteriaceae) and functional genes (e.g., carbon degradation, denitrification, nitrification, phosphorus transport, and organic phosphorus mineralization), which positively affected wheat grain yield and SMF. Interestingly, irrigation did not significantly affect rhizosphere microbial composition and function, wheat grain yield, and SMF, but enhanced stability of wheat grain yield in C and M. In conclusion, our results suggest the potentials of interactions between agricultural practices (fertilization and irrigation) and crop nutritional requirements in maintaining yield sustainability and SMF within intensive wheat-maize cropping system in the North China Plain.