Earthworms are considered as “ecosystem engineers” for their contributions to improve soil aeration, drainage and transformation of minerals and plant nutrients to available and accessible forms favourable for crop yield. Since earthworms account for the highest biomass among tropical soil invertebrate macro-fauna soil quality depends on population density, species diversity and activity level of earthworm community. On the other hand earthworm species composition and population structures are directly affected due to the changes in land use patterns with different plantations in tropics. So earthworm population dynamics and the influence of farming practices on earthworms are of particular interest to organic growers.

Direct effect of plant species on soil organisms are caused by the plant’s inputs of organic matter above and below ground, while indirect effect of plants on underground soil biota include shading, soil protection and uptake of water and nutrients by roots. Reports are available that exotic plantation favours establishment of exotic species with its dominance in terms of density and biomass and decrease in biodiversity.

Incorporation of vermicompost has been shown to influence the physico-chemical properties of plant growing substrates. Literature is available on the impact of vermicompost on growth and productivity of different economically important cash crops. However, information is lacking on the farming of pineapple either with chemical fertilizer or organic manure. In spite of the fact that pineapple (Ananas comosus; family: Bromeliaceae) is the most common and tasty fruit crop with great demand to the people of north-east India including Tripura, information is lacking on organic farming of this economically important cash crop.

Despite various contributions made by a good number of earthworm scientists in vermitechnology, ecology and role of earthworms in various habitats, literature is scanty on the distribution, diversity, ecology and role of tropical earthworms in monoculture plantation. On the basis of the above facts, the proposed investigation is designed to elicit for the first time detailed studies on Earthworm resources in the pineapple plantations of Tripura in relation to some physico-chemical parameters of soil; Earthworm community characteristics in the monoculture pineapple and mixed fruit plantations of West Tripura; Community characteristics of earthworms under pineapple plantations of different age groups in West Tripura; Effects of vermicompost on the community structure of earthworms and yield of pineapples.