Quality comparison of conventional compost, vermicompost and chemically-enriched compost

The aim of present study was to evaluate the chemical and biochemical quality of various enriched composts prepared by heap and pit methods and compare it with conventional compost. The various composts viz., phosphocompost (PC), nitrogen-enriched phosphocompost (NPC), vermicompost (VC) and phosphorus-enriched vermicompost (PVC) were compared with conventional compost. These composts were produced by using chemical amendment in case of chemically-enriched compost whereas vermicompost was prepared by inoculating the epigeic earthworms Eisenia foetida and Perionyx excavatus with and without rock phosphate. The mineral matter content (ash %) was higher in all the enriched composts in comparison to conventional compost. The total organic C and water-soluble carbon were lower, whereas, total mineral constituents (NPK) were higher in the enriched compost and vermicompost. In general, there was no significant variation in the content of macro-and micronutrients between phosphorus-enriched vermicompost and the other chemically-enriched composts; however, vermicompost prepared by only earthworm inoculation was slightly better than conventional compost. The period of decomposition was almost the same (105±10 days) among the enriched composts, whereas, in case of coventional compost, the decomposition period was 175±5 days. As regards biochemical quality of the composts, it was found that conventional compost exhibited less amount of total phenol, alkaline and acid phosphatase enzyme activities, but a higher dehydrogenase activity. The greater dehydrogenase activity in case of conventional compost is an indicator of partial decomposition of the compost. There was no variation in terms of chemical and biochemical constituents whether the method of compost preparation is by heap or pit methods. Although, the vermicompost was better than conventional compost, it could be still further improved by rock phosphate enrichment.