1. GENERAL INTRODUCTION Conservation, reuse, recycling and composting are the solid waste management philosophies of the 21st century. Earthworms are Annelidan Oligochaetes, forming the major terresterial macrofauna which constitute more than 80 per cent of the soil invertebrates biomass. Earthworms are nature’s own tiller, aerator, crusher, composter, moisture builder of the top soil and above all soil ultimate friend and benefactor (Watanabe, 1975; Lal, 1988). Earthworms have 600 million years of experience as a biomanager of soil (Bhawalkar, 1994). Aristotle and Darwin have referred earthworms as “the intestine of the earth” and the “nature’s plough to man”. At present earthworms are extensively used for production of vermicompost from organic wastes, vermiprotein, soil reclamation, soil detoxification and abatement of environmental pollution (Garg et al., 2005). Earthworms have increasingly been used for organic wastes such as animal waste, plant waste, industrial waste, municipal garbage and industrial sludges management and production of nutrient rich organic manure-vermicompost. The earthworms and/or vermicompost are used to: degrade organic waste, indicate environmental pollution, detoxicate polluted soil, turnover the soil, prepare protein rich animal feed, produce medicine, improve soil physico-chemical properties, restore soil fertility, induce plant growth, increase plant productivity and reduce pathogenic microbes. In a nutshell, earthworms may referred as waste stabilizer, compost manufactures, protein producers, pollution preventers, ecosystem engineers and in short Biogold. 2 1.1. Earthworm Reynolds (1994) reported worldwide occurrence of 3,627 terrestrial earthworms. So far, 402 species and subspecies of earthworms belonging to 66 genera and 10 families are known from India. Indian earthworm’s fauna is represented by 357 native and 45 exotic peregrine species (Julka, 2001). On the basis of morphological nature and ecological strategies, earthworms have been classified into three groups by Bouche (1977). He has classified earthworms into epigeic or surface dwelling forms (eg. Perionyx excavatus, Eisenia fetida, and Eudrilus eugeniae), anecic (or) top soil dwelling forms (eg. Lampito mauritii and Pheretima diplotetratheca) and endogeic or bottom soil dwelling (deep burrowing) forms (eg. Lumbricus terrestris and Allolo bophora longa). Among the three functional groups, epigeic species have greater potentiality for degrading organic wastes, and endogeic species have better capacity of protein conservation and soil turn over whereas anecic species remain inbetween these two species (Dash and Senapati, 1980). Edwards (1988) characterized seven species of earthworms which are utilized for vermicomposting in different parts of the world. They are E. eugeniae, P. excavatus, E. fetida, E. andrei, L. rubellus, Dendrobaena veneta, and Polypheretima elongata. Indian earthworms other than Eudrilus eugeniae and Eisenia fetida that could possibly be utilized for vermicomposting of organic wastes are Lampito mauritii, Dendrobaena repaensis, Metaphise houlleti (Julka and Sanapati, 1993; Kaushik et al., 1999). 3 1.2. EARTHWORM IN ORGANIC WASTE MANAGEMENT In recent years, the problem of efficient disposal and management of organic solid wastes has become more vigorous due to rapidly increasing populations, intensive agriculture and industralization. Production of large quantities of organic wastes all over the world poses major environmental (offensive odor, contamination of ground water, and soil) and disposal problems (Edwards 1985). According to Vimal and Talashilkar (1983) 22683 lakh tons of organic waste are annually available in India, with gross NPK content of 13967 thousand tons. Recently, Bhattacharjee (2002) reported that India produces about 3000 million tons of organic waste annually which could be utilized for recovering important resources like fertilizer, fuel, food and fodder. This huge amount of organic waste also has the potentiality to produce 400 million tons of plant nutrients besides biogas and alcohol. The generation of solid waste in India is increasing in an alarming way leading to the great environmental degradation due to the putricible matter present in these wastes. The complex structural composition of organic wastes resist their breakdown, so the natural decomposition becomes a slow process, resulting in the accumulation of these wastes in large quantities which in turn, lead to environmental pollution and cause hygenic problem. Under the present conditions of acute energy crisis and environmental degradation with the growth of industries, cities, and ever increasing human population, it has become essential to develop 4 appropriate technology for recovery of energy from non-conventional sources like organic wastes which are once thought to be of no use. Actually wastes are nothing but misplaced and mismanaged wealth of organic resources and wastes become a source of renewable energy if properly utilized. Proper utilization of organic wastes can improve soil physical condition and environmental quality as well as provide nutrients for plants (Bhardwaj, 1995). Now the major problem is concerned with the method of utilization or recycling of organic wastes. The present method of utilization of organic wastes by land spreading, open land dumping and traditional composting are inefficient and yet there remains a major problem of utilizing these wastes profitably in order to realize their full potential and avoid pollution. Further, traditional method of composting resulting in losses of about 55% of organic matter and from 30 to 50% of nitrogen (Ketkar, 1993). The employment of earthworms for waste management as an efficient alternative method is suggested by many researchers (Kale, 1994; Ramalingam, 1997; Parthasarathi and Ranganathan, 1999; Atiyeh et al., 2000; Arancon et al., 2003; Manivannan et al., 2004; Suthar, 2006). Because of their food and feeding habits the earthworms should be considered nature’s most useful converters of organic wastes into organic manure. 5 1.3. THE GROWTH AND REPRODUCTION OF EARTHWORM The growth of earthworms is most commonly measured in terms of increase in weight (biomass). The increase in biomass of the whole body (growth rate) is expressed as in mg or gram per worm per day or in terms of percentage (Maynard et al., 1983). Growth in earthworms according to one view is by elongation of predestined segments (Kale, 1994) and the other considers it due to addition of new segments during post-emergence growth. Reinecke and Viljoen (1988) by their study on Eudrilus eugeniae found the latter view to be applicable. The feasibility of using earthworm for waste management is dependent on a fundamental knowledge about the basic parameters like the survival, growth and reproduction of earthworm species. Environmental conditions and population density are known to affect growth and reproduction of earthworms. The potential of earthworms as the waste processor has been well estabilized (Neuhauser et al., 1979; Kale, 1994; Elvira et al., 1998; Parthasarathi et al., 1999; Karmegam and Daniel, 2000; Ramalingam, 2004; Norman et al., 2007; Herlihy, 2007). But the wastes decomposing potentiality depends upon biomass production and reproduction capacity of those earthworm species selected for vermiculture. Earthworms’ growth, maturation, cocoon production and reproduction potential are not only influenced by the environmental conditions alone but also strongly affected by the quality and availability 6 of food (Reinecke and Viljoen, 1990; Garg et al., 2005). Hence, to understand the full potentiality of compost worms as waste decomposer, it is essential to study the growth and reproduction of earthworms that could be cultured on variety of organic wastes. Earthworms have been shown to require food rich in nitrogen, cellulose, microorganism for their growth and reproduction (Hartenstein and Bisesi, 1989; Ranganathan and Parthasarathi, 1999). Earthworms continue to grow throughout their lives, but the rate of growth declines following sexual maturity (Reinecke et al., 1992; Edwards and Bohlen, 1996; Singh, 1997; Kale, 1998). However, reports on the chemical changes during breakdown of the organic waste by the activity of the earthworm are scarce (Albanell et al. 1998; Ghosh et al., 1999). The aim of the present investigation is to document the stepwise chemical changes during the composting of kitchen waste by an indigenous species of earthworm. Such study is necessary to determine the time of vermistabilization for harvesting of quality compost from a particular type of waste. 1.4. VERMICULTURE AND VERMICOMPOSTING TECHNOLOGY “Vermiculture” is the rearing of earthworms in a suitable substrate (food medium) in order to raise their population and biomass. Vermiculture is practiced for the mass production of earthworms with the multiple objectives of waste management, soil fertility, detoxification and vermicompost production for sustainable agriculture (Edward, 1988). Vermicomposting is defined as “the biodegradation of organic matter 7 occurring when earthworm feeds on them under control conditions” (Hervas et al., 1989). 1000 kg of moisture organic wastes can be converted into 300 kg of vermicompost by earthworms in 45 to 60 days. One kg of earthworm could produce 10 kg of vermicompost in 45-60 days (Gunathilagaraj, 1994). Vermiculture through vermicomposting involves hundred times higher resource generation when compared to the conventional composting. For example vermicomposting