Composition of the Substrate Governs the Efficiency of Eudrilus eugeniae and the Outcomes of Biostabilisation during the Vermicomposting of Rice Straw and Husk

Background: In developing countries, sustainable management of rice straw and husk remains a major challenge due to their lignocellulosic nature. Vermicomposting using Eudrilus eugeniae offers a promising approach to converting these residues into organic fertilizers. However, the composition of the substrate may influence earthworm growth, reproduction and composting efficiency. Methods: An 90-day experiment was conducted using eight substrates based on either rice husk (RH) or rice straw (RSt), either alone or in combination with cow dung (CD) and/or chicken waste (CW). Each treatment was inoculated with five adult earthworms. Physicochemical parameters, including pH, moisture content, total organic carbon (TOC), total nitrogen (TN), phosphorus (P), potassium (K) and magnesium (Mg), were analysed before and after composting. Earthworm population and cocoon production were also recorded. Result: Substrate composition significantly affected vermicomposting performance. TOC and the C/N ratio decreased in all treatments, particularly in RSt + CD, where the C/N ratio decreased from 51.85 to 15.05, indicating effective stabilisation. TN and P increased across the substrates. The combined substrate (RSt + RH + CD + CW) produced the highest earthworm population (354 ± 62.08) and cocoon production (127.66 ± 18.14), whereas RH alone performed poorly.