Seedling quality, biomass promotion and nutrient uptake potential of AMF, Azotobacter and Pseudomonas in Azadiracta indica under nursery condition

The efficacy potential of Arbuscular-Mycorrhizal fungi (Glomus interaradics and Acaulospora scrobiculata), Phosphorus Solubilizing Bacteria (Pseudomonas straita) and Azotobacter (Azotobacter chroococcum) were determined in Azadirachta indica seedling. Fifty gram AMF, 10g Pseudomonas and 10g Azotobacter were inoculated in rhizosphere of newly recruited seedlings individually or in integration. Seedling quality index enhanced significantly recorded maximum by 62.56% and seedling vigour by 63.85 percent with tripartite inoculation of AMF+PSB+Azotobacter over uninoculated seedling. Similarly, the seedling biomass was also enhanced substantially up to 72.42% with the same treatment. The biomass increment was also observed in seedlings inoculated with AMF+Azotobacter (60.0%), AMF+PSB (24.78%), and PSB+Azotobacter (17.60%) in comparison to control plants. The seedling dependency to microbial inoculants was found highest of 72.13% on AMF+PSB+Azotobacter followed with AMF+Azotobacter (60%). The microbial tripartite gave best results in production of superior quality planting material than with bipartite inoculation. The percent root infection by AMF recorded maximum 66.0% in seedling with AMF+Azotobacter followed with AMF+Azotobacter compared to control seedlings (7.66%). Similarly the integration of AMF+PSB+Azotobacter was found most effective in the uptake of nitrogen, phosphorus and potassium content which were increased by 42%, 105% and 137% respectively. The highest content of Fe (10.71 µg/g), Zn (0.18 µg/g) Mg (16.74 µg/g), Mn (0.98 µg/g) and Cu (0.12 µg/g) were analysed on inoculation with AMF, PSB and Azotobacter. The combined inoculation of AMF+PSB+Azotobacter was given best results in improving the quality of seedling, biomass and nutrient uptake of Azadirachta indica which has opened the new implications for their use in healthy seedlings production in nursery for the supply of ever increasing demands for afforestation and reforestation.