Chemical and Biochemical Changes during Vermicomposting and Conventional Composting of Different Organic Residues

Composting basically being a microbiological process, enzymatic activities can be part of a reliable measure of compost stability and maturity. Assay of different chemical and biochemical changes during composting is important for the optimization of the process and the quality of the end product. This study was, therefore, conducted to compare the chemical and biochemical properties of composts prepared from four organic residues of varying C/N ratios i.e. sugarcane trash, weeds, vegetable market waste and rice straw. Four residues were composted separately by vermicomposting and conventional method of composting. The results showed that vermicomposting is preferred over composting to overcome the deficiencies in the long duration for decomposition apart from low nutrient status in composting. Total organic carbon (TOC) and C/N ratio decreased while total N content increased with the passage of time during composting in all the organic residues, however the per cent decrease was more in vermicomposting than composting in a particular period of time. Among different organic residues used for study highest total N content was recorded in vegetable market waste compost with a low C/N ratio, whereas reverse trend was observed in case of rice straw compost. The enzyme activities i.e. urease, phosphatase, dehydrogenase and cellulase were decreased with increasing the composting period in all the organic residues. However, higher enzyme activity was recorded in vermicomposting over composting of different organic residues and within the organic residues, vegetable market waste recorded higher enzyme activities except cellulase, which was higher in rice straw compost. Weed compost exhibited on par with vegetable market waste. Type of organic residue used for composting showed significant influence on chemical and biochemical properties. Vermicomposting should be preferred over composting with high N value and less C/N ratio apart from high biochemical parameters.