Impact of Rubber Leaf Litter Vermicompost on Earthworm Population and Pineapple (Ananas comosus) Productivity in West Tripura, India

Background: The task of modern agriculture is to protect the environment, reduce expenses, and promote social stability while maintaining high agricultural yields. Organic soil additions, such as vermicompost, can help achieve such a goal by increasing earthworm populations by providing a nutrient-dense substrate. However, there is little information on the impact of organic manure or vermicompost on soil biota, particularly ecosystem engineers such as earthworms.

Purpose: Rubber leaves are abundant in agro-waste, and pineapple is Tripura's most economically important fruit crop. So, in our present study, different amounts of rubber leaf vermicompost have been applied to the soils of pineapple plantations to determine their effects on earthworms—the soil ecosystem engineers, coupled with the vegetative growth and yield of pineapples.

Methods: During 30 months of field trial (2010–2012) in ICAR regional station, Lembucherra, West Tripura, the control plot (T0) received no fertilizer, while experimental plots were fertilized with four different amounts of vermicompost viz. T1 (5 tons ha-1 year-1), T2 (10 tons ha-1 year-1), T3 (20 tons ha-1 year-1) and T4 (30 tons ha-1 year-1).

Results: A significant (p < 0.05) but gradual increase in density (up to T3 treatment) and biomass (up to T4 treatment) of earthworms were recorded with the increasing amounts of vermicompost. During the second year, the average length and width of leaves, number of leaves per plant, plant girth, fruit weight, fruit yield, and fruiting percentage were highest in the T3 plot compared to other treated plots and control.

Conclusion: The present study reveals that crop yield is very much related to the concentration of vermicompost, beyond the level of which production declines and increase in vegetative growth, fruit weight, and fruiting percentage of pineapple are strongly linked with the soil pH, av. P, av. K, clay content, and the earthworm density of soils.