**2.10 Effect on chemical properties of soil**

Earthworms bring about mineralisation of organic matter and thereby release the nutrients in available forms that can be taken up by the plants (Edwards and Bohlen, 1996). Organic matter that passes through the earthworm gut is egested in their casts, which is broken down into much finer particles, so that a greater surface area of the organic matter is exposed to microbial decomposition (Martin, 1991). Earthworms have major influences on the nutrient cycling process in many ecosystems (Edwards and Bohlen, 1996). These are usually based on four scales (Lavelle and Martin, 1992):


Earthworms contribute nutrients in the form of nitrogenous wastes (Ismail, 2005). Their casts have higher base-exchangeable bases, phosphorus, exchangeable potassium and

Earthworms and Vermiculture Biotechnology 91

improving reclaimed soils (Boyle *et al.,* 1997; Butt, 1999). Some experiments on improving impoverished soils by stimulating earthworm populations have been reported (Butt *et al.,* 1997). A successful introduction of earthworms in reclaimable soil could be achieved by overcoming factors like unfavorable moisture conditions, excessive fluctuation of surface

In recent years, disposal of organic wastes from various sources like domestic, agriculture and industrial has caused serious environmental hazards and economic problems. Burning of organic wastes contributes tremendously to environmental pollution thus, leading to polluted air, water and land. This process also releases large amounts of carbon dioxide in the atmosphere, a main contributor to global warming together with dust particles. Burning also destroys the soil organic matter content, kills the microbial population and affects the physical properties of the soil (Livan and Thompson, 1997). It has been demonstrated that earthworms can process household garbage, city refuse, sewage sludge and waste from paper, wood and food industries (Kale *et al.,* 1982; Muyima *et al.,* 1994; Edwards and Bohlen, 1996; Ismail, 2005). In tropical and subtropical conditions *Eudrilus eugeniae* and *Perionyx excavatus* are the best vermicomposting earthworms for organic solid waste management (Kale, 1998). The use of earthworms in composting process decreases the time of

stabilisation of the waste and produces an efficient bio-product, *i.e.,* vermicompost.

Organic farming system is gaining increased attention for its emphasis on food quality and soil health. Vermicompost and vermiculture associated with other biological inputs have been actually used to grow vegetables and other crops successfully and have been found to be economical and productive (Ismail, 2005; Ansari and Ismail, 2008).In this regard, recycling of organic waste is feasible to produce useful organic manure for agricultural application. Compost is becoming an important aspect in the quest to increase productivity of food in an environmentally friendly way. Compost is becoming an important aspect in the quest to increase productivity of food in an environmentally friendly way. Vermicomposting offers a solution to tonnes of organic agro-wastes that are being burned by farmers and to recycle and reuse these refuse to promote our agricultural development in more efficient, economical and environmentally friendly manner. Both the sugar and rice industries burn their wastes thereby, contributing tremendously to environmental pollution thus, leading to polluted air, water and land. This process also releases large amounts of carbon dioxide in the atmosphere, a main contributor to global warming together with dust particles. Burning also destroys the soil organic matter content, kills the microbial population and affects the physical properties of the soil (Livan and Thompson, 1997). Therefore organic farming helps to provide many advantages such as; eliminate the use of chemicals in the form of fertilizers/pesticides, recycle and regenerate waste into wealth; improve soil, plant, animal and human health; and creating an ecofriendly, sustainable and

Vermitechnology is the use of surface and subsurface local varieties of earthworm in composting and management of soil (Ismail, 2005). Darwin (1881) has made their activities the object of a careful study and concluded that 'it may be doubted if there are any other

temperature and lack of suitable food (Satchell, 1983).

**6. Earthworms and organic solid waste management** 

economical bio-system models (Ansari and Ismail, 2001a).

**6.1 Vermitechnology** 

manganese and total exchangeable calcium. Earthworms favour nitrification since they increase bacterial population and soil aeration. The most important effect of earthworms may be the stimulation of microbial activity in casts that enhances the transformation of soluble nitrogen into microbial protein thereby preventing their loss through leaching to the lower horizons of the soil. C: N ratios of casts are lower than that of the surrounding soil (Bouché, 1983). Lee (1983) summarised the influence of earthworms on soil nitrogen and nitrogen cycling. According to him, nitrogenous products of earthworm metabolism are returned to the soil through casts, urine, mucoproteins and dead tissues of earthworms.
