Vermi-modification of ruminant excreta using Eisenia fetida

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Ruminant excreta presents a significant waste management challenge.
• Sustainable methods are needed to convert excreta into valuable resources.
• Vermicomposting offers a promising biological approach for waste valorization.

Purpose of the Study:

• To investigate the vermicomposting potential of different ruminant excreta using Eisenia fetida.
• To evaluate the impact of vermicomposting on nutrient content and earthworm performance.
• To assess the maturity and stability of the resulting vermicompost.

Main Methods:

• Preparation of 11 feedstocks from sheep, cow, buffalo, and goat excreta in various ratios.
• Cultivation of Eisenia fetida on semi-composted feedstocks for 90 days under laboratory conditions.
• Analysis of nutrient content (NPK, organic carbon, organic matter), heavy metals, and C/N ratio in raw and vermicomposted materials.

Main Results:

• Vermicomposting successfully transformed ruminant excreta into odor-free, homogenous vermicompost with enhanced nutrient content.
• Eisenia fetida exhibited significant growth across all feedstocks, with the largest biomass gain in buffalo excreta.
• Buffalo excreta also supported the highest earthworm fecundity, followed by goat + buffalo excreta.
• Vermicomposted materials showed reduced organic carbon and organic matter but increased NPK and heavy metal content compared to raw feedstocks.
• C/N ratios ranged from 15.37 to 38.56, indicating mature and stabilized vermicompost.

Conclusions:

• Vermicomposting is an effective method for upgrading ruminant excreta into high-quality organic fertilizer.
• Buffalo excreta is the most suitable feedstock for Eisenia fetida-based vermicomposting, yielding superior earthworm growth and reproduction.
• The resulting vermicompost is mature, stable, and enriched in essential nutrients, offering a sustainable alternative to chemical fertilizers.