Effects of chemical fertilizer application on soil properties, banana ( Musa paradisiaca ) yields, and soil microbiomes in a long-term cultivation field

Due to climate change and increasing food demand, conventional agriculture relies heavily on chemical fertilizers. This study investigated the effects of chemical fertilizer application on soil properties, banana ( Musa paradisiaca ) yields, and soil microbiomes in a long-term cultivation field. Metagenomic analysis of the 16S rRNA gene provided a comprehensive overview of soil microbial diversity and functional potential. Nitrogen, phosphorus, and potassium (NPK) fertilizers at 0, 119, 238, and 476 kg ha −1 were applied monthly for one year. Fertilizer application significantly altered soil properties and microbial community dynamics but had no significant effect on banana yields. Higher fertilizer rates reduced soil pH and increased available phosphorus and exchangeable potassium, while total nitrogen and organic matter remained relatively unchanged. Elevated NPK inputs increased the abundance of specific microbial taxa, including Bacillus , Streptomyces , uncultured bacterium JG30-KF-AS9, and Nitrospira , while Xanthobacteraceae, bacteriap25, Micromonosporaceae, Nocardioides , Subgroup 6, and Gemmatimonadaceae consistently represented core taxa across all treatments. Pearson’s correlation analysis revealed that soil total nitrogen and exchangeable potassium were positively correlated with the abundance of key plant growth-promoting and nitrifying taxa, including Pseudomonas and Nitrospira , whereas soil pH was negatively correlated with Acidothermus , Nitrospira , and Bacillus , but positively correlated with Subgroup 6. Functional gene profiles further indicated enhanced anaerobic processes associated with carbon, nitrogen, and sulfur cycling. The findings suggest that long-term nutrient accumulation resulting from repeated fertilization and crop residue inputs may sustain banana crops throughout the 10-month production period without additional fertilization. Together, these findings highlight the need for fertilizer regimes tailored to long-term soil nutrient status, contributing to both sustainable agriculture and microbiome-informed crop management.