Influence of litter quality on soil microbial effects in home-field advantage of litter decomposition in two subtropical forests

The home-field advantage (HFA) hypothesis posits that leaf litter decomposes faster at its native sites (“home”) than in foreign sites (“away”). While litter quality critically regulates decomposition and HFA, the interplay among litter quality, soil nutrients, and microbial activity in driving HFA remains poorly understood. We examined these dynamics in subtropical forests using Pinus massoniana (low-quality litter) and Schima superba (high-quality litter) in a reciprocal transplant decomposition experiment, including a 1:1 mixed-litter treatment. Our results revealed pronounced HFA effects in both forest stands, but litter quality was negatively correlated with both the decomposition rate and HFA magnitude. Soil nutrients regulated HFA effects, accounting for 65% of the variation in low-quality litter (vs. 25% for high-quality litter). Low-quality litter exhibited greater sensitivity to soil microbial metabolic activity. Soil microbial biomass enhanced HFA in the low-quality litter forest stand but suppressed it in the high-quality forest stand. Enzymatic activity (e.g. β-1,4-glucosidase) directly mediates HFA, particularly in high-quality litter. These findings underscore litter quality as a pivotal factor governing HFA through its interactions with soil nutrients and microbial metabolism, with implications for predicting biogeochemical cycles in forest ecosystems.