Trichoderma strains accelerate maturation and increase available phosphorus during vermicomposting enriched with rock phosphate.

AIMS: To suggest microbial inoculation as a tool to shorten organic residues stabilization and increase rock phosphate (RP) solubilization through vermicomposting, thus increasing nutrient content in plants and making it more appealing to farmers. Two Trichoderma strains were inoculated alone or combined in a RP apatite-enriched vermicompost. Stability and plant-available phosphorus levels were monitored for 120 days. METHODS AND RESULTS: Observable higher total organic carbon reduction in the treatment with the combined Trichoderma strains, followed by the inoculation with T. asperellum and T. virens. Combined Trichoderma and inoculation with T. virens increased humic acids (HA) content in 38·2 and 25·0%, respectively; non-inoculated vermicompost with T. asperellum increased it by 15·0%. The combined Trichoderma strains and T. virens achieved the stability index based on the humic/fulvic acids (HA/FA) ratio after 120 days. T. asperellum, combined Trichoderma and T. virens increased the citric acid soluble-P content in 83·2, 62·2 and 49·5%, respectively, compared to the non-inoculated vermicompost. CONCLUSIONS: Inoculation with combined T. asperellum and T. virens efficiently accelerated vermicompost stabilization; T. asperellum increased the citric acid soluble-P in the final product. SIGNIFICANCE AND IMPACT OF THE STUDY: Combined Trichoderma inoculation and RP enrichment improves the vermicompost quality, increasing HA and citric acid soluble-P, recycling organic waste nutrients and reducing agricultural dependence on phosphate fertilizers.