Deciphering agricultural and forest litter decomposition: Stage dependence of home-field advantage as affected by plant residue chemistry and bacterial community

Background and aims: The ‘home-field advantage’ (HFA) hypothesis posits that plant litters decompose faster in their native habitat than elsewhere. Uncovering the mechanisms of HFA effect during litter decomposition is crucial for understanding ecosystem nutrient cycling and carbon budgeting. Methods: We investigated HFA effect in agricultural and forest ecosystems through a two-year reciprocal transplant field experiment in a temperate region, using post-harvest maize straw and mixed forest litter. We examined the temporal dynamics of HFA by analyzing the interplay influence of plant residue quality and soil microbial community composition. Results: We observed that the presence and strength of HFA varied depending on the stage of litter decomposition, with the difference in initial chemistry between litters diminishing over time. Our findings indicate a variable HFA, ranging from neutral to positive, linked to the persistence of plant residue compounds (as inferred by Aromatic/Aliphatic ratio). In specific, we found a positive mean HFA effect for mixed litter and a negative effect for maize straw, highlighting that lower quality plant residues may enhance HFA. Moreover, we found that HFA was positively affected by dissimilarity in bacterial community between ‘home’ and ‘away’ soils in later stages of litter decomposition, which was indirectly impacted by bacterial regulation of N-related hydrolases activities, indicating a bacterial-driven rather than fungal-driven influence on HFA effect. Conclusion: Our study underscores the importance of considering stage-dependence in HFA studies, emphasizing the influence of plant residue quality and highlighting the greater role of bacterial communities over fungi in affecting the dynamics of HFA effect.