Enhancing soil health with Bacillus velezensis UFV 3918 boosts phosphorus and nutrient accumulation in sugarcane

Bacterial inoculation is a promising strategy for optimizing the use of phosphate fertilizers, although the ability of different strains to reduce phosphorus (P) inputs remains to be investigated. This study evaluated the effects of Bacillus velezensis UFV 3918 (Bv), alone or combined with monoammonium phosphate (MAP), on the bioavailability of P and other nutrients, as well as on the chemical and microbiological properties of soil cultivated with sugarcane. The trial was conducted in a completely randomized design with six treatments: absolute control (without MAP) (AC), commercial control (recommended MAP dose – 3/3 MAP) (CC), Bv, Bv+1/3 MAP, Bv+2/3 MAP, and Bv+3/3 MAP. The Bv and Bv+1/3 MAP treatments promoted average increases in soil P content (22.0%), root volume (9.9%), root diameter (6.7%), soil basal respiration (11.4%), and the activity of fluorescein diacetate (17.4%), urease (9.1%), and acid phosphatase (9.3%), compared with the CC. Additionally, Bv alone led to greater accumulation of P, K, Fe, B, and Cu in the shoot. Multivariate analysis indicated similar responses among Bv, Bv+1/3 MAP, and Bv+2/3 MAP. Shoot P accumulation was positively correlated with microbial and chemical soil attributes, particularly soil enzyme activities, P and Ca content, and Fe and Mn accumulation. In contrast, the negative correlation between microbial biomass and root development suggests that enhanced soil biological activity may reduce the need for extensive root growth. Thus, B. velezensis UFV 3918 shows potential to reduce MAP dependence while promoting efficient plant nutrition and healthier soils.