The Influence of Bacterial Inoculants and a Biofertilizer on Maize Cultivation and the Associated Shift in Bacteriobiota During the Growing Season

Maize (<i>Zea mays</i> L.) relies heavily on nitrogen and phosphorus inputs, typically supplied through organic and inorganic fertilizers. However, excessive agrochemical use threatens soil fertility and environmental health. Sustainable alternatives, such as poultry manure (PM) and plant growth-promoting rhizobacteria (PGPR), offer promising solutions. This study examines the effects of a phytobiotic bacterial formulation (PHY), composed of <i>Bacillus subtilis</i> and <i>Microbacterium</i> sp., applied alone and in combination with PM, on maize's rhizosphere bacteriobiome across key growth stages. Field trials included four treatments: a control, PHY-coated seeds, PM, and combined PHY_PM. The results show that early in development, the PM-treated rhizospheres increased the abundance of beneficial genera such as <i>Sphingomonas</i>, <i>Microvirga</i>, and <i>Streptomyces</i>, though levels declined in later stages. The PHY_PM-treated roots in the seedling phase showed a reduced abundance of taxa like <i>Chryseobacterium</i>, <i>Pedobacter</i>, <i>Phyllobacterium</i>, <i>Sphingobacterium</i>, and <i>Stenotrophomonas</i>, but this effect did not persist. In the PM-treated roots, <i>Flavisolibacter</i> was significantly enriched at harvesting. Overall, beneficial bacteria improved microbial evenness, and the PHY_PM treatment promoted bacterial diversity and maize growth. A genome analysis of the PHY strains revealed plant-beneficial traits, including nutrient mobilization, stress resilience, and biocontrol potential. This study highlights the complementarity of PM and PGPR, showing how their integration reshapes bacteriobiome and correlates with plant parameters in sustainable agriculture.