Bioconversion of legume cover crop waste into organic fertilizer based on integrated composting-vermicomposting method

Abstract Circle weeding is a mechanical strategy in controlling legume cover crop (LCC) entanglement at the reclamation area of PT Mitrabara Adiperdana Tbk, Indonesia. Circle weeding generates up to 3.83 tons/ha leavings of LCC biomass, serving as recycled raw material for compost but with poorly degraded biomass. This experimental study attempted to discover an effective procedure to generate LCC Fertilizer by testing the integration between composting and vermicomposting. The chopped LCC were fermented using bioactivator for 21 days, then added with cow manure at different ratios as bulking materials for vermicomposting. The results showed that the recovery value obtained from the composting stage was 64.43%. The most ideal composition was 50:50 LCC to cow dung with 12-day vermicomposting which resulted in 93.27% recovery value. Laboratory analysis on the nutrient content indicated the fertilizer was suitable for soil amendment. Parameters of heavy metals, micronutrients, and N are up to par, whereas P and K for solid organic fertilizer based on KEPMENTAN RI No. 261/KPTS/SR.310/M/4/2019 were subpar. Further development is advised.