Litter nutrient availability promotes home-field advantage during litter decomposition

Home-field advantage (HFA) hypothesis proposes that long-term interactions between litter substrates and decomposer communities accelerate litter decomposition in home relative to away sites. However, whether HFA consistently regulates the nutrient release across different nutrient types during litter decomposition, and the mechanisms underlying these effects, remain unclear. We conducted a reciprocal litter transplant experiment in a subtropical region using four litter species from cropland and forest ecosystems differing in initial chemical traits. We quantified the release dynamics of structural (C, N, P) and mineral (Ca, Mg, Mn) nutrients and characterized soil fungal community composition throughout decomposition. We observed HFA significantly accelerated the release of both structural and mineral nutrients. HFA exhibited distinct relationships with explanatory variables across nutrient type. HFA for structural nutrients and Mg release was positively related to their respective nutrient availability. In contrast, HFA for Ca release was positively associated with fungal community dissimilarity. HFA for Mn release showed no relationship with either nutrient availability or fungal community dissimilarity. Our findings demonstrate that HFA for litter nutrient release is nutrient specific and governed by distinct mechanisms. Contrary to the conventional view that recalcitrant substrates universally enhance HFA, litter nutrient availability promotes and strengthens HFA expression. Our findings highlight that litter decomposition is jointly regulated by substrate nutrient availability, decomposer community composition, and environmental filtering, with their relative contributions varying across nutrient types.