Earthworm Communities in Paddy (Oryza sativa) Fields of West Tripura (India).

Paddy is one of the most important food crops in India. In Tripura of north east India, paddy covers 78–90% of cultivable areas with hydromorphic clay-rich acidic soils. As earthworms have important role in above-ground crop production, the present study deals with the earthworm communities in the soils of wet land paddy agro-ecosystem of West Tripura (India). The study was conducted during May 2015 to August 2017. Earthworms were collected from the paddy fields by TBSF monolith (25 × 25 × 30 cm) digging and hand sorting method. Temperature, moisture, pH and organic matters were estimated from 0 to 15 cm depth soils. Biological parameters such as density, biomass, relative abundance and ecological parameters such as indices of diversity, dominance etc. were measured. A total of 7 earthworm species belonging to 4 families and 5 genera were recorded: [Almidae Glyphidrilus sp. (near to gangeticus)], Moniligastridae (Drawida assamensis, Drawida papillifer papillifer and Drawida sp.), Megascolecidae (Metaphire houlleti, Perionyx excavatus) and Glossoscolecidae (Pontoscolex corethrurus). The average density and biomass of earthworms in the paddy plantations were 163 ind. m⁻² and 56 g m⁻² respectively. Diversity and dominance indices of earthworms of paddy plantations were 0.46 and 0.60 respectively. Glyphidrilus sp. contributed more than 50% biomass and density of earthworm community and probably had a great role in paddy production due to enormous deposition of casts ('cast hills') in the rhizosphere zone of paddy plants. [ABSTRACT FROM AUTHOR]