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ABSTRACT:
The sub-lethal exposure (20% and 60%) of LC^sub 50^ of herbicide butachlor of different feed materials of buffalo dung with agro-wastes of different exposure periods was observed in the laboratory. There was time and dose dependent Sub-lethal (20% and 60%) of LC^sub 50^ of different exposure periods were observed after treatment of different combination of buffalo dung with agro-wastes. The prolong duration in clitellum development (days), significant reduction in cocoon production/worm and hatchlings/cocoon as well as survival of hatchlings were observed. The sub lethal effect of herbicide butachlor on the earthworm Eutyphoeus waltoni was both time and dose dependent. The prolong duration of clitellum development was observed in 60% LC^sub 50^ of all exposure periods in buffalo dung. Maximum per cenatage of cocoon production, hatchling/cocoon and survival of hatchling was observed in 20% LC^sub 50^ of all exposure periods in buffalo dung, wheat straw and gram bran combination. There was no mortality observed in control. There was no significant (P< 0.05, t- test) difference between control and 20% of LC^sub 50^ of BD+Ws+Gb of all exposure periods shows that the vermicompost of feed material of this combination was more potential for use in agricultural fields because it enhance the tolerance power of earthworm Eutyphoeus waltoni against herbicide butachlor.
KEYWORDS: Herbicide, Butachlor, buffalo dung, Agro-wastes, Sub lethal exposure, Eutyphoeus waltoni, Reproduction , Development.
INTRODUCTION:
Earthworms are the most important biotic component of soils which play an important role in mineralization and breakdown of organic matter. They are also important contributors to the recycling of carbon and nitrogen in the ecosystem and most suitable bio-indicator organisms for testing chemicals of the soil (Edwards and Lofty 1977; Callahan 1988; Goats and Edwards 1988; Cock et al., 1980; Gobi et al., 2004).Earthworm have been used model animals for the study the effect of agrochemicals on soil fauna. Herbicides manifest low toxicity on earthworms, but indirectly can produce the reduction of the populations by decreasing the organic matter input and weed coverage. Earthworms are also important contributors to the recycling of carbon and nitrogen in the ecosystem. The herbicide 2,4-D has very toxic for growth and reproduction of earthworm Eisenia fetida (Helling et al., 2000; Zhou et al., 2007;Corriela and Moreira 2010).Gobi (2010) reported that the percentage of...