Sustainable Agriculture through Black Soldier Fly Larvae Frass: Impacts on Soil Properties, Shallot Crop Productivity, and Cost Analysis

Sustainable agriculture faces challenges in enhancing soil health and crop productivity while minimizing costs. Applying organic amendments like Black Soldier Fly Larvae (BSFL) frass presents a potential solution, yet its comprehensive effects on soil properties and crop yield remain underexplored. This study aimed to evaluate the impact of BSFL frass on soil properties, shallot crop productivity, and associated cost analysis. A field experiment was conducted with six treatments, including varying rates of BSFL frass and Nitrogen-Phosphorus-Potassium (NPK) fertilizer. Soil samples were analyzed for pH, soil organic carbon (SOC), total nitrogen, and available phosphorus, while shallot yield was measured post-harvest. Results indicated that BSFL frass significantly improved soil pH and SOC levels, with the highest yield recorded in the treatment combining BSFL frass and NPK fertilizer. Treatment BSFL 22.5 ton ha−1 + NPK 250 kg ha−1 notably outperformed other treatments in both yield and profitability, suggesting that an optimal combination of organic and inorganic inputs can substantially enhance productivity and financial returns. These findings indicate that BSFL frass not only improves soil health and crop yield but also offers a cost-effective alternative to conventional fertilizers, promoting sustainable agricultural practices. Future research should focus on the long-term effects and scalability of BSFL frass application in diverse cropping systems.