COS 130-5
Does home-field advantage on litter C and N mineralization persist along a land-use gradient?
Several studies concluded that decomposition frequently occurs more rapidly when litter decomposes beneath the plant species from which it is derived (i.e. at home) than beneath different plant species (i.e. away), which has been referred to as ‘home field advantage’ (HFA). However, while the theory underlying the HFA hypothesis is progressively taking shape, evidence for HFA effects is strongly context dependent. This is because most studies involved reciprocal litter transplant between highly contrasting ecosystems characterized by an important variability of soil pedogenesis. Here, in a microcosm experiment under controlled conditions, we tested the HFA hypothesis using a land-use gradient (grassland, plantation, culture and forest) with soil originating from a one-hectare plot, varying only with human disturbance and the presence of various plant covers (Festuca arundinacea Schreb., Robinia pseudoacacia L., Triticum aestivum L. and Fagus sylvatica L.). During 202 days of incubation, we measured regularly carbon (C) and nitrogen (N) mineralization and changes in substrate quality and microbial community structure (PLFAs).
Results/Conclusions
C and N mineralization dynamics were influenced by litter species, soil characteristics and their interactions. Overall, C mineralization strongly increased with litter of high-soluble C content (i.e. Festuca arundinacea Schreb. and Robinia pseudoacacia L.) whereas N mineralization/immobilization was dependent of the litter stoichiometry, with lowest mineralization rates associated to highest C:N ratios (i.e. Triticum aestivum L.). HFA effects on C mineralization were more important for litters of highest qualities but transient depending of microbial communities and substrate quality over time. However, the HFA patterns on N mineralization were contrasted to those of C, with highest mineralization rates of N at home for litters of lowest qualities (i.e. Fagus sylvatica L.). Our results show that (i) HFA effects on C and N mineralization are asynchronous and sometimes dissimilar; (ii) HFA and HFD (home-field disadvantage) varied with time and the evolution of litter quality and microbial communities structure. Our data suggest that HFA effects are not similar along a land-use gradient but may be an important determinant for how decomposers respond to various litter supply.