Municipal sludge as precursors in Chinese medicinal herbal residues composting for plant-growth biostimulant production: Priming effects and microbial mechanism

Abstract

This study proposed a feasible strategy to promote plant-growth biostimulants (PGB) production using sludge as an alternative precursor in plant-derived substances composting, providing new insights into the nutrient-driven intrinsic regulatory mechanisms of microbial ecology. Our results indicate that the intervention of sludges achieved rapid polymerization and accumulation of humic substances (HS) within a brief timeframe. The nutrients in the sludge drove the establishment of a unique microbial interaction network, optimizing the utilization of carbon/nitrogen sources, and resulting in accelerated PGB production. The positive responses of microbial physiological behaviors were the intrinsic factors in regulating microbial community composition and metabolisms, which impact the transformation of organic matter into PGB. Therefore, targeted strategies that induce microbial physiological behaviors could substantially enhance PGB production efficiency. Overall, this study provides a novel sustainable approach to sludge resource management, providing deeper insights into the relationship between microbial physiological behavior and PGB production.