Bioinoculants and Vermicompost Improve Ocimum basilicum Yield and Soil Health in a Sustainable Production System

With respect to the adverse effects of chemical fertilizers on the environment and their higher cost, an alternative method of improving soil fertility has been tested. Application of vermicompost (VC) (produced from de-oiled waste) along with efficient bioinoculants (nitrogen fixer: Bacillus sp., JN700924; phosphate solubilizer: Bacillus megaterium, ATCC 14581; plant growth promoter: Pseudomonas monteilii, HQ 995498; arbuscular mycorrhizal fungus (AMF): Glomus intraradices) in different combinations were evaluated on Ocimum basilicum. VC along with bioinoculants-treated plots showed a significant improvement in biomass (15.1-56%), essential oil content (26.7-48.2%), and essential oil yield (44.7-108.4%) over control. The major constituent of essential oil (i.e., methyl chavicol) was significantly improved in T-3 (VC + Bacillus sp.), T-5 (VC + P. monteilii), and T-6 (VC + G. intraradices) treated plants as compared to control (T-1). Significant improvement in microbial counts, percent root colonization of AMF, and alkaline phosphatase activity were recorded; maximum in bioinoculants along with VC-treated plots. Improvement in soil organic carbon (4.2-51.16%), NH4+-N (27.0-55.3%), NO3--N (-8 to 60.33%], available P (15.2-43.5%), and available K (0.4-20.8%) were found in VC along with bioinoculants-treated plots. The diethylene triamine pentaacetic acid extractable Fe (109-154 mg kg(-1) soil) was more influenced by VC along with bioinoculants than other micronutrients (Cu, Mn, and Zn). The results suggest that an integrated use of VC with bioinoculants improves soil health and essential oil yield of O. basilicum.