Agriculture Reference
In-Depth Information
tivity is found to enhance the beneficial microflora and suppress harmful
pathogenic microbes. Soil wormcasts are rich source of micro and macro-
nutrients, and microbial enzymes (Lavelle and Martin 1992). Vermicom-
posting is an efficient nutrient recycling process that involves harnessing
earthworms as versatile natural bioreactors for organic matter decomposi-
tion. Due to richness in nutrient availability and microbial activity ver-
micomposts increase soil fertility, enhance plant growth and suppress the
population of plant pathogens and pests. This review paper describes the
bacterial biodiversity and nutrient status of vermicomposts and their im-
portance in agriculture and waste management.
9.2 EARTHWORMS
Earthworms are capable of transforming garbage into 'gold'. Charles Dar-
win described earthworms as the 'unheralded soldiers of mankind,' and
Aristotle called them as the 'intestine of earth', as they could digest a wide
variety of organic materials (Darwin and Seward 1903; Martin 1976). Soil
volume, microflora and fauna influenced by earthworms have been termed
as “drilosphere” and the soil volume includes the external structures pro-
duced by earthworms such as surface and below ground casts, burrows,
middens, diapause chambers as well as the earthworms' body surface and
internal gut associated structures in contact with the soil (Lavelle et al.
1989; Brown et al. 2000). Earthworms play an essential role in carbon
turnover, soil formation, participates in cellulose degradation and humus
accumulation. Earthworm activity profoundly affects the physical, chemi-
cal and biological properties of soil. Earthworms are voracious feeders of
organic wastes and they utilize only a small portion of these wastes for
their growth and excrete a large proportion of wastes consumed in a half
digested form (Edwards and Lofty 1977; Kale and Bano 1986; Jambhekar
1992). Earthworms intestine contains a wide range of microorganisms,
enzymes and hormones which aid in rapid decomposition of half-digested
material transforming them into vermicompost in a short time (neary 4-8
weeks) (Ghosh et al. 1999; Nagavallemma et al. 2004) compared to tra-
ditional composting process which takes the advantage of microbes alone
and thereby requires a prolonged period (nearly 20 weeks) for compost
