Effect of Storage Conditions on Vermicompost Quality

To study the effects of storage conditions on vermicompost, an experiment was conducted with freshly prepared, un-dried fresh vermicompost (60% moisture), and pre-air dried vermicompost (30% moisture) stored in polythene bags for a period of four weeks under different moisture and aeration conditions. Three different storage conditions were tested by placing fresh and pre-dried vermicompost in: (1) open bags, (2) holed bags and (3) sealed bags. Vermicompost properties were analysed weekly for four weeks after storage. The moisture content declined in both fresh and pre-dried vermicompost, with a maximum decline under open bag condition, followed by holed and sealed bags. In the sealed airtight bags with fresh vermicompost, a rapid decline in total organic carbon, nitrogen and electrical conductivity was observed during the first and second week of storage, possibly due to microbially-triggered volatilization losses. However, such decline was lacking in pre-dried vermicompost. In open and holed bags, the carbon and nitrogen were retained and rather increased during storage, possibly due to ongoing aerobic decomposition and no volatilization losses. The highest nutrient quality was observed under predried holed bag conditions, possibly due to optimal microbial activity releasing nutrients, combined with no volatilization losses. It was concluded that fresh vermicompost must be air-dried before its storage in bags. Storage of air-dried vermicompost under aerobic conditions using open/ holed bags appears to be the best option for retaining nutrients and quality of vermicompost.