Use of vermicomposting biotechnology in recycling fly-ash for agricultural use

Abstract

Numerous coal fired plants operating in different parts of the world produce huge amount of
fly-ash every year. Such large scale generation of this waste material poses several problems,
the most important ones being environmental pollution and occupation of large areas of land
for storage and disposal. Hence, the urgent and imperative needs to overcome these problems
through not only safe disposal but also gainful utilization of these materials cannot probably
be overemphasized. Among various uses of fly-ash, its application to agricultural soils has
shown encouraging results in many countries owing to the fact that the waste contents many
essential plant nutrients in varying concentrations. However, the major problem of recycling
fly-ash in agriculture is that most of the nutrient elements in this waste material remain
largely in insoluble forms and hence do not become available to plants in required
concentrations. Under this context, use of fly-ash along with organic materials appears to be
an effective proposition. In view of high efficiency of vermicomposting biotechnology in
increasing the pace of the composting process and also in encouraging higher availability of
different nutrients with the help of epigeic earthworms, a series of studies were carried out to
assess the possibility of improving the usability of fly-ash in agriculture in combination with
organic wastes through adoption of vermicomposting. The results of the investigation showed
vermicomposting to increase the availability of different major and micro nutrients in fly-ash.
On farm trials carried out on use of vermicomposted fly-ash and organic wastes showed use
of 15 ton per hectare of vennicomposted fly-ash to result in significant yield increments in
potato cultivation. This also reduced the application of 40% of mineral fertilization for this
cultivation.