Abstract
The Home-Field Advantage (HFA) hypothesis proposes that plant litter decomposes more rapidly in its native soil environment. However, the relative influence of litter quality, microbial communities, soil properties, and their interactions in driving HFA effects remains unclear. We addressed this gap using a reciprocal litter-soil-inoculum manipulation experiment that included maize stover with cropland soil from a temperate agricultural ecosystem and mixed forest litter with forest soil from a temperate forest ecosystem. Contrary to expectations based on elemental stoichiometry, maize stover (C:N = 44) decomposed more rapidly than forest litter (60% versus 38% mass loss), despite its substantially higher initial C:N ratio (forest litter C:N = 26). This faster decomposition was associated with a lower aromatic:polysaccharide carbon ratio, indicating that litter chemistry better predicted decomposition than C:N ratio alone. Although maize stover exhibited no detectable HFA effect, forest litter exhibited a significant and positive HFA response. We then tested whether microbial–soil affinity, operationally defined as the degree of alignment between microbial communities and their native soil environment, predicted HFA dynamics. We found that the highest-affinity treatment, in which native microbial communities remained paired with their native soil environment, increased forest litter mass loss by 67% relative to non-native microbial inoculation after 360 days. Forest soils also sustained greater microbial biomass and extracellular enzyme activities, which were associated with the enrichment of taxa such as oligotrophic Chloroflexia involved in the degradation of both labile and structurally complex carbon fractions. Together, these findings indicate that HFA for lower-quality forest litter emerged from interactions between litter chemistry and native microbial–soil associations, demonstrating that carbon chemistry and native microbial-soil associations outweighed elemental stoichiometry in predicting rates of litter decomposition.