Valorization of waste lignocellulosic biomass for soil amendment: A critical assessment and strategic framework

Global agriculture faces a dual crisis: accelerating soil degradation, which depletes soil organic carbon (SOC) and water-holding capacity (WHC), coupled with the buildup of unutilized (waste) lignocellulosic biomass (LCB). Valorizing this waste LCB into sustainable soil amendments offers a key solution to improve soil water retention and crop yields. However, a thorough review of current conversion pathways, including pyrolysis, torrefaction, solid-state fermentation (SSF), and deep eutectic solvents (DES), highlights significant technological and economic challenges. These issues include high energy requirements, low product stability, slow processing speeds, and poor economic viability. Despite these practical obstacles, meta-analyses strongly support the fundamental effectiveness of LCB-derived amendments in restoring SOC, boosting crop production, and remediating contaminants. Therefore, the main challenge has shifted from proving agronomic effectiveness to developing cost-effective production methods that enhance energy efficiency and stability. Scaling these technologies for industrial applications requires an integrated approach that combines technical optimization, economic feasibility, and data-driven management to restore degraded lands and ensure food security.