Management of invasive weed Chromolaena odorata (Siam weed) through vermicomposting: An eco-approach utilizing organic biomass valorization

Abstract

The present research study has evaluated the roles of vermicomposting and elucidated the efficacy of selected earthworm ( Eisenia fetida ) in the eco-management of invasive weed Chromolaena odorata by way of organic biomass valorization. The different trial sets with different proportions of weed samples and sundried cowdung had shown a trend in change of pH (T2>T1>T3>T4>T5), EC (T1 > T2 > T3 > T4>T5) and C/N ratio as T5 (22.89 ± 3.00) > T4 (20.59 ± 0.42) > T3 (16.76 ± 1.4) > T1 (13.88 ± 0.11) > T2 (13.18 ± 0.60). Furthermore, a significant change in population parameters of earthworm like biomass, number, cocoon production was noticed among different vermicomposting trial sets as T2 > T1 > T3 > T4 > T5 > PC. The present research study has revealed T2 trial (60% weed sample and 40% cowdung) to be better towards maintenance of both earthworm and physicochemical parameters. In T2 trial set, a biodegradation of cellulose, lignin polymers and nitrogen mineralization of plant biomass were well noticed at 1081 cm −1 , 1456 cm −1 and 850-770 cm −1 respectively. Furthermore, the SEM-EDX study deciphered fragmentation alongside a trend of change in the distribution of different elements like a reduction of weight for carbon (45.27% to 25.64%), sodium (0.56% to 0.31%), aluminium (0.24% to 0.19%) coupled with an increase in percentage for oxygen (34.12% to 46.12%), silicon (4.15% to 8.12%), magnesium (2.12% to 3.28%), phosphorus (0.25% to 0.39%), potassium (0.35% to 0.87%), sulphur (0.16% to 0.31%), chlorine (0.21% to 0.45%) and calcium (0.15% to 0.28%) among the T2 samples. Such findings had corroborated to the role of extracellular enzymes present in the samples as confirmed through API-ZYM TM analysis. Therefore, the trial set using weed: cowdung as 6:4 facilitates the valorisation of weed samples and production of nutrient enriched vermicompost. • Biomass valorization of Chromolaena odorata is practicable through vermitechnology. • Weed: Cowdung ratio as 60:40 has supported the development of earthworm populations which lead to nutrient enrichment. • FTIR spectroscopy at wavenumber 1081 cm -1 , 1456 cm -1 and 850-770 cm -1 has confirmed breakdown of cellulose, lignin polymers and nitrogen mineralization respectively. • Biodegradation of weed through vermicomposting was confirmed through SEM. • SEM-EDX study has confirmed an increase in distribution of different atoms like P, Ca, K, Mg and Cl among vermicompost samples.