Comparative evaluation of tank and open bed method of vermicomposting

Vermicomposting is one of the simplest methods of recycling organic waste materials into a high quality compost. It is a major component of organic farming and has been gaining popularity among the farmers because of its manifold benefits. The present study was conducted during the year 2020-21in four locations namely, Barjar, Sandheli, Sariahtoli and Bali villages of Nalbari district, Assam with two treatments viz., open bed method and tank method with a view to compare the duration of composting, earthworm population build up and production of quantity of vermicompost between the two methods. For tank method concrete tank of size 1.8 m x 0.9 m x 0.6 m (Lx B x H) was constructed whereas for open bed method of same size were prepared on the ground demarcating with bamboo. Organic waste materials such as banana pseudostem, water hycianth and other farm wastes and cowdung were used as raw materials and species of earthworm Eisenia foetida were inoculated @ 200 numbers per tank/ bed. The results indicated that duration of composting, earthworm population build up and quantity of vermicompost produced were significantly higher in open bed method of vermicomposting as compared to the tank method of vermicomposting. The time taken for vermicomposting was lowered by 20 days, maximum population was increased by 133 numbers and quantity of vermicompost produced significantly higher by 13 kg per bed in open bed method than the tank method. The open bed method was proved to be more feasible, suitable and beneficial in terms of production cost, time and labour saving, earthworm multiplication and generate higher economic return than the tank method. This method can be adopted for large scale commercial production of vermicompost.