EARTHWORM COMMUNITY CHARACTERISTICS IN THE SOILS OF TWO TERRESTRIAL LAND USE SYSTEMS (BANANA AND FLOWER PLANTATIONS) IN WEST TRIPURA (INDIA)

Banana is the most established, economically important fruit crop in India. Floriculture is also of great commercial importance. As earthworms are important soil macrofauna which have a great role in soil fertility and crop production, the present study deals with the differences in the earthworm communities in the soils of banana and flower plantations of West Tripura (India). The study was conducted during March 2015 to November 2017. Earthworms were collected from the banana and flower plantations by digging (25 cm x 25 cm x 30 cm) and hand-sorting method. Temperature, moisture, pH and organic matter were estimated from 0-15 cm depth of soils because earthworms are mostly concentrated within 15 cm depth. Biological parameters such as density, biomass, relative abundance and ecological parameters viz. indices of diversity, dominance etc. were measured. Analysis of earthworm communities in the studied sites revealed the presence of 12 species of earthworms belonging to 4 families and 10 genera in the banana plantations and 7 species of earthworms belonging to 4 families and 6 genera in the flower plantations. The similarity quotient was 63% between the two habitats (banana and flower). The average density and biomass of earthworms in the flower plantations were 186 ind. m-2 and 92 g m-2 respectively which were significantly (p< .05) higher than that of the mean density (154 ind. m-2) and biomass (76 g m-2) of earthworms in the banana plantations. Shannon diversity index was comparatively higher in the banana plantations (0.78) than that of flower plantations (0.60) whereas, Simpson dominance index was more in flower plantations (0.42) than that in banana plantations (0.23). Less number of earthworm species in the flower gardens compared to banana plantations was possibly due to its monoculture nature and higher management practices. Monthly fluctuations of earthworm density (juvenile, young and adult) along with soil temperature (°C) showed that pre-monsoon to post-monsoon i.e. April-November are the most suitable periods for earthworm activity and reproduction.