Characterization of Biostimulant-enriched Aquatic Weed Compost and Biochar Derived from Water Hyacinth (Eichhornia crassipes)

Abstract

Aims: Production and characterisation of aquatic weed compost (AWC) and aquatic weed biochar (AWB) after enrichment with microbial (Bacillus consortium, Probiotic-PGPR Mix-1) and non-microbial (Seaweed Extract from Kappaphycus alvarezii at 2%, Protein Hydrolysate at 0.5%) biostimulants. Study Design: The experiment was conducted using a completely randomised design with eight treatments and three replications. Place and Duration of Study: The study was conducted at the Model Organic Farm, Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, between September 2025 and January 2026. Methodology: The aquatic weed was collected from Vellayani Lake. The collected aquatic weed was used to produce vermicompost and biochar. The matured compost and biochar were enriched with microbial biostimulants, namely Bacillus consortium (B1) and Probiotic-PGPR Mix-1 (B2), and non-microbial biostimulants, namely Seaweed Extract (Kappaphycus alvarezii) (B3) and Protein Hydrolysate (B4). These enriched manures were characterised for nutrient content. Results: AWC-based treatments exhibited higher organic carbon (13.66 - 15.83%), lower C:N ratios (6.86 - 13.65), and greater moisture content (23.45 - 31.85%), while AWB-based treatments showed significantly higher EC (13.7 - 18.4 dS/m) and micronutrient concentrations. T2 (PGPR Mix-1 + AWC) recorded the lowest C:N ratio among compost treatments (6.86), indicating superior maturity, whereas T8 (Protein Hydrolysate + AWB) exhibited the lowest overall C:N ratio (2.57). Conclusion: The biostimulant enrichment significantly enhances the manurial quality of both aquatic weed compost and biochar, and the selection of appropriate biostimulant-manure combinations can optimise nutrient availability for crop production.