Does understory plant community explain soil organic matter and function in nemo-boreal pine woodland ?

Mills, R.*; Fujii, Kazumichi*; Jassey, V.*; Heffernan, L.*; Koarashi, Jun   ; Mattiasen, C.*; Robroek, B.*; Buttler, A.*

Currently, estimates of soil carbon stock and turnover in northern forest soils ignore, to a large extent, the variability of understory plant communities, and their contribution to the within-system heterogeneity that might occur. To explore how understory plant communities may explain soil carbon stock and turnover, we analysed podsol O-horizons for organic matter characteristics and microbial communities and functions across contrasting cover of functional groups in a nemo-boreal pine forest in southern Sweden. We found plant community cover and biomass to be a poor predictor of organic matter content and quality, and of the microbial community composition to be poorly related to both. The results imply a disconnection between plant community composition and longer-term soil carbon stores in complex systems on an ecosystem scale.