Combined application of manure and straw with chemical fertilizers enhances soil quality and maize yield by regulating bacterial community composition and diversity: a long-term field study.

Introduction: Against the backdrop of excessive chemical fertilizer application and challenges to global food security, promoting the development of sustainable green agriculture has become urgently necessary. Methods: Based on a long-term field experiment, this study investigated the relationships between microbial communities and soil quality under different fertilization practices. Six fertilization treatments were established: no fertilizer (CK), mineral nitrogen alone (N), combined mineral nitrogen and phosphorus (NP), manure alone (M), combined mineral fertilizer and manure (MNP), and combined mineral fertilizer and straw (SNP). Results: MNP and SNP significantly increased the soil quality index (SQI) and maize yield, with MNP showing greater improvement than SNP. Soil organic carbon (SOC), total nitrogen (TN), and microbial biomass carbon (MBC) were identified as the main contributors to SQI and maize yield. The relative abundances of dominant bacterial phyla and genera increased under MNP and SNP treatments, among which Discussion: In conclusion, MNP and SNP enhanced soil quality and crop yield by optimizing soil properties, thereby increasing bacterial diversity and the abundance of dominant bacterial communities. The study provides a deeper theoretical basis for the optimization of organic fertilization techniques and the regulation of soil health.