In this article we will discuss about the meaning and process of vermicomposting.
Meaning of Vermicomposting:
Vermicomposting is the operation of composting process of organic materials by involving earthworms. It is a sustainable biofertilizer generated from organic wastes. Vermicompost is an excellent source of nutrients for vegetables, ornamentals, fruits and plantation crops. Using vermicompost one can get 10-15% more crop yield, besides improvement in quality of the products.
For the first time, in 1970, vermicomposting was started in Ontario (Canada). In recent years the USA, Japan and Philippines are the leaders of vermicompost producers. So far least attention has been paid in India. But in recent years, Government and nongovernment organisations (NGOs) are trying to popularise the vermicomposting process.
Through an NGO, Pithoragarh Municipality (Uttaranchal) has started vermicomposting by using a thermotolerant earthworm Eisenia foetida. Vermicomposting is also being done at Shanti Kunj (Haridwar). One kg earthworm can consume 1 kg organic materials in a day.
They secrete as casting which are rich in Ca, Mg, K, N and available P. Depending on substrate quality, vermicompost consists of 2.5-3.% N,1-1.5% P and 1.5-2.0% K, useful microroganisms (bacteria, fungi, actinomycetes, protozoa), hormones, enzymes and vitamins.
Earthworms make tunnels and mix soil. Thus they aerate the soil which promotes the growth of bacteria and actinomycetes. Consequently, microbial activity of soil is increased due to increase in enzymatic and biological activity of earthworms.
About 500 species of earthworms are known in India and over 3,000 in the world. The most common members of the earthworm to be used in vermicomposting include: Eisenia andrie. E. foetida, Dravida willsii, Endrilus euginee, Lamito mauritii, Lubrieus rubellus and Perionyx excavatus.
Process of Vermicomposting:
Process of vermicomposting can be done in pits or concrete tanks, wells or wooden crates. A pit of 2×1×1 m3 dimension (1 m maximum depth) is dug under a shade to prevent the entry of water during rain (Fig. 33.1).
Wooden bricks or pebbles are spread on the bottom of pit followed by coarse sand to facilitate the drainage. It is covered by a layer of loamy soil which is moistened and inoculated by earthworms. It is covered by small lumps of fresh or dry cattle dung followed by a layer of hay or dry leaves or agro wastes.
Every day for about 20-25 days water is sprinkled over it to keep the entire set up moist. Until the pit is full dry and green leaves are put into the pit in each week. Vermicompost is ready after 40-45 days. Vermicomposting appears soft, spongy, dark brown with sweet smelling. Then it is harvested and kept in dark. It is sieved and packed in polythene to retain 20% moisture content.