Compost Maturity Assessment Using Physicochemical, Solid-State Spectroscopy, and Plant Bioassay Analysis

The vermicompost produced from flower waste inoculated with biofertilizers was subjected to compost maturity test: (i) physicochemical method (pH, OC, TN, C:N); (ii) solid state spectroscopic analysis (FTIR and C-13 CPMAS NMR); and (iii) plant bioassay (germination index). The pH of vermicompost was decreased toward neutral, C:N ratio < 20; reduced organic carbon with increased nitrogen indicates the compost attains maturity. The final vermicomposts result shows reduction of complex organic materials into simple minerals which indicates the maturity of the experimental vermicompost product than the control. The increased aliphatic portion incorporated with flower residues may be due to the synthesis of alkyl, O-alkyl, and COO groups by the microbes present in the gut of earthworm. Plant bioassays are considered the most conventional assessment of compost maturity analysis, and subsequently, it shows the effect of vermicompost maturity on the germination index of Vigna mungo.