Vermi-Biotechnological Management of Rubber Plantation Wastes for Nutrient Recovery Using Indigenous Epigeic Earthworms of Tripura, India

Abstract

Rubber (Hevea brasiliensis Muell. Arg.) cultivation is an important agro-economic activity in Tripura, India, but plantation operations generate lignocellulosic residues that decompose slowly and retain potentially recoverable nutrients. This study evaluated the vermi-biotechnological conversion of rubber-plantation waste using indigenous epigeic earthworms under controlled conditions. Three treatments were considered: rubber waste without earthworms (T1), rubber waste inoculated with indigenous epigeic earthworms (T2), and rubber waste amended with cow dung and inoculated with indigenous epigeic earthworms (T3). Changes in physicochemical properties, cellulase and ligninase activities, earthworm survival, reproduction, and biomass gain were assessed during vermicomposting. After 60 days, organic carbon declined from 38.4 ± 1.2% in the initial waste to 24.8 ± 1.1% in T2 and 21.6 ± 0.9% in T3, while total nitrogen increased from 1.05 ± 0.06% to 1.78 ± 0.09% and 2.05 ± 0.08%, respectively. The C:N ratio decreased to 13.6 ± 0.9 in T2 and 10.8 ± 0.7 in T3. Available phosphorus and potassium also increased, while earthworm survival reached 86 ± 3% in T2 and 93 ± 2.5% in T3. Biomass gain at day 60 was greater in T3 than in T2. These findings indicate that indigenous epigeic earthworms can facilitate the stabilisation and nutrient recovery of rubber-plantation residues, with cow-dung amendment supporting greater vermicomposting performance under the experimental conditions.