Purpose: Vermicomposting can be enhanced by inoculating vermibeds with beneficial microbes, thereby improving its biofertilizer properties. This study examined how phosphate-solubilizing bacteria (Pseudomonas putida Tabriz) and nitrogen-fixing bacteria (Azotobacter sp.) influence enzyme activity in vermicompost produced from different organic substrates (litter, wheat straw, wood dust, and compost). Method: A mixture of cow manure and organic materials (1:8 w/w) was vermicomposted in 3-kg pots with Eisenia fetida earthworms. After four months, bacterial inoculants were introduced, and samples were analyzed at 0, 4, 7, and 10 months for acid phosphatase, urease, and cellulase activities. Results: Bacterial inoculation significantly increased enzyme activity, with peaks observed at 4–7 months. Overall, bacterial inoculation significantly increased enzymatic activity, with the highest values observed at 4 and 7 months after inoculation. Specifically, P. putida Tabriz enhanced cellulase and urease activities, while Azotobacter sp. improved phosphatase activity in the vermibeds. The highest enzyme activities were recorded in: compost (acid phosphatase, 1864 μg pNP/g.h), leaf litter (urease, 460 μg NH₄⁺-N/2h), and wood dust (cellulase, 1568 μg GE/g.24h). Enzyme activity gradually increased during the experiment but declined toward the end of the study period. Conclusion: Vermicompost effectively serves as a carrier for beneficial microbes, enhancing enzyme activity and soil health. This approach offers a sustainable way to improve agricultural productivity through biofertilization.
Ebrahimi et al. (Mon,) studied this question.