Decoupling of topsoil and subsoil controls on organic matter dynamics in the Swiss Alps

Our results show a clear divergence in predictors of OM thermal stability in the litter, topsoil, and subsoil layers. The composition of OM correlated with its thermal stability in the litter layer but not in mineral soil horizons, where the supply rate of fresh organic material and the physical and chemical characteristics of the pedogenic environment appeared important instead. This study offers direct confirmation that soil OM dynamics are influenced by different ecosystem properties in each soil layer. This has important implications for our understanding of carbon cycling in soils under a changing climate.