Effects of rubber leaf litter vermicompost on earthworm population and yield of pineapple (Ananas comosus) in West Tripura, India

Purpose Rubber leaves are the abundant agro-waste andpineapple, the most economically important fruit crop inTripura. So, in our present study, different amounts ofrubber leaf vermicompost have been applied to the soils ofpineapple plantation to determine their effects on earthworms—the soil ecosystem engineers, coupled with thevegetative growth and yield of pineapples.Methods During 30 months of field trial (2010–2012) inICAR regional station, Lembucherra, West Tripura, thecontrol plot (T0) received no fertilizer, while experimentalplots were fertilized with four different amounts of vermicompostviz. T1 (5 tons ha-1 year-1), T2 (10 tonsha-1 year-1), T3 (20 tons ha-1 year-1) and T4 (30 tonsha-1 year-1).Results A significant (p.05) but gradual increase indensity (up to T3 treatment) and biomass (up to T4 treatment)of earthworms were recorded with the increasingamounts of vermicompost. During the second year, averagelength and width of leaves, number of leaves per plant,plant girth, fruit weight, fruit yield and fruiting percentagewere highest in the T3 plot compared to other treated plotsand control.Conclusion The present study reveals that crop yield isvery much related to the particular concentration of vermicompost,beyond the level of which production declinesand increase in vegetative growth, fruit weight and fruitingpercentage of pineapple are strongly linked with the soilpH, av. P, av. K, clay content and the earthworm density ofsoils.