Influence of Phosphorus and Phosphate-solubilizing Bacteria on Soil Microbial Dynamics in Mustard under Gmelina-Based Agroforestry

Abstract

The impact of phosphorus (P) levels and phosphate-solubilizing bacterium (PSB) inoculation techniques on soil microbial dynamics in mustard (Brassica juncea) grown in agroforestry systems based on Gmelina arborea is examined in this study. Three phosphorus levels (30, 40, and 50 kg/ha) and three PSB inoculation techniques (soil, seedling, and combination soil + seedling) were used in the split-plot design experiment, which was carried out at the Jawaharlal Nehru Krishi Vishwa Vidyalaya Research Farm in Jabalpur. Azotobacter, Rhizobium, total bacteria, and fungi were among the soil microbial communities that were examined after harvest. The findings showed that phosphorus levels had no discernible impact on the number of microorganisms. Nonetheless, PSB inoculation techniques showed notable results; in every category, the soil + seedling inoculation combination consistently produced the greatest microbial populations. For instance, the populations of Azotobacter, Rhizobium, and fungi were 28.55 CFU × 10⁵ g⁻¹, 20.58 CFU × 10⁶ g⁻¹, 45.15 CFU × 10⁶ g⁻¹, and 7.72 CFU × 10⁵ g⁻¹, respectively. These results highlight how PSB inoculation and agroforestry systems can work together to improve soil health and nutrient dynamics, which will support sustainable mustard farming methods.