Effects of Bacillus subtilis N24 combined with liquid water-soluble carbon fertilizer on soil chemical properties and microbial community of fresh maize

Recent years have witnessed increasingly extensive application of microbial fertilizers in agriculture. However, the effectiveness of microbial fertilizers remains inconsistent because of the significant effects of soil's physical and chemical properties on microbial colonization. Therefore, exploring the scientific application of microbial fertilizers is of great significance for improving their application effect on crops. This study aimed to investigate the effects of Bacillus subtilis combined with liquid water-soluble carbon fertilizer on soil chemical properties and the rhizosphere microbial community of fresh maize. It employed a pot experiment design, incorporating five distinct treatments: T1 (liquid water-soluble carbon fertilizer), T2 (B. subtilis N24 fermentation solution), T3 (B. subtilis + liquid water-soluble carbon fertilizer), CK0 (clean water), and CK1 (conventional fertilization). Illumina high-throughput sequencing was used to analyze corn potting soil. The results indicated that the fertilization treatments influenced the chemical properties of the rhizosphere soil of fresh maize in the following order: T3 > CK1 > T2 > T1 > CK0. The T3 treatment significantly increased the contents of total nitrogen, available nitrogen, total phosphorus, available phosphorus, potassium, and organic matter (P < 0.05). It enhanced nitrogen availability and effectively preserved phosphorus and organic matter within the soil. Furthermore, the treatment enriched the microbial community diversity in the corn rhizosphere, thereby significantly increasing the abundance of Firmicutes, Acidobacteriota, Bacteroidota, Mortierellomycota, and Basidiomycota (P < 0.05), demonstrating superior effects compared with the individual applications. The soil properties were strongly linked to microbial composition, as shown by the redundancy analysis (P < 0.05). In summary, the combined application of B. subtilis N24 and liquid water-soluble carbon fertilizer enhanced the chemical properties and fertility of the soil for fresh maize while also positively influencing the structure of the microbial community. This study provides a theoretical foundation for developing novel fertilizer application models for corn cultivation.