Effect of N deposition on the home-field advantage of wood decomposition in a subtropical forest

Abstract

Nitrogen (N) can influence the functions of forest ecosystems by altering the abundance and activity of microbial and faunal communities. The impact of N deposition on the home-field advantage (HFA) effect of dead wood decomposition remains unclear. In this study, a 24-month field reciprocal wood translocation experiment was conducted with three levels of N deposition (control (N0), 60 (N1) and 120 (N2) kg N ha−1 yr−1) in both Platycarya strobilacea (PL) forest and Cryptomeria japonica (CR) forest in subtropical China, where anthropogenic N deposition is among the highest in the world. The influence of soil biota groups on the HFA effect was partitioned using different sizes of mesh bags. We found that N1 facilitated wood decomposition by enhancing wood faunal and microbial community abundance and soil extracellular enzyme activity. However, N2 promoted wood decomposition in coarse-mesh bags by attracting more fauna and in fine-mesh bags by increasing fungal growth. In the control (CK) treatments, we found a 4.55-fold greater HFA effect in fine-mesh bags than in coarse-mesh bags. On average, a 6.6- and 4.8-fold greater HFA effect was observed with N1 treatment than with N2 and control treatments, respectively, and these differences were associated with greater differences in microbial and faunal communities between home and away fields. In summary, our results indicated that low levels of anthropogenic N enrichment could increase the HFA effect on wood decomposition through the modification of microbial and faunal communities in the wood decomposition process and thereby influence C sequestration, with peak carbon emissions and carbon neutrality reached in the next few decades in the forests of subtropical regions.