Influence of Litter Quality on Microbial Activity and Soil Nutrient Cycling: A Review

Abstract

Litter decomposition is a fundamental pathway through which organic matter and nutrients enter the soil, thereby regulating microbial activity, soil fertility, and ecosystem productivity. Litter quality, defined by the chemical, physical, and biological attributes of plant residues, plays a central role in controlling decomposition rates and nutrient cycling processes. This review synthesises current knowledge on how variations in litter quality influence microbial communities, enzymatic activity, and the cycling of carbon (C), nitrogen (N), phosphorus (P), and other essential nutrients in soil ecosystems. Key chemical indicators such as carbon-to-nitrogen (C: N) ratio, lignin content, polyphenols, and elemental stoichiometry strongly determine microbial accessibility, decomposition pathways, and the balance between nutrient mineralisation and immobilisation. Physical traits, including leaf toughness, thickness, cuticle development, and silica content, further regulate microbial colonisation and faunal fragmentation. Microbial functional groups respond differentially to litter quality, with bacteria dominating the decomposition of labile substrates and fungi driving the breakdown of recalcitrant compounds. Interactions among litter quality, microbial activity, soil fauna, and environmental factors generate complex feedbacks that shape soil organic matter dynamics and nutrient availability. The review also highlights the roles of litter mixing, priming effects, and management practices in modifying decomposition outcomes. Understanding litter quality–microbe interactions provides a critical foundation for sustainable soil management, improved nutrient use efficiency, and enhanced ecosystem resilience under changing land-use and climatic conditions.