Comparing the temperature sensitivity of organic matter decomposition in oxic and oxygen-deprived soils

Current studies on the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition mainly focus on aerobic conditions. However, variations and determinants of Q10 in oxygen (O2)-deprived soils remain unclear. Here we incubated three grassland soils under oxic, suboxic, and anoxic conditions subjected to varying temperatures to compare variations in Q10 in relation to changing substrates. No consistent variation was found in Q10 under various O2 conditions. Further analysis of edaphic properties demonstrated that substrate carbon quality showed a strong influence on Q10 in oxic soils, whereas nitrogen limitation played a more important role in suboxic and anoxic soils. These results suggest that substrate carbon quality and nitrogen limitation may play roles of varying importance in determining the temperature sensitivity of SOM decomposition under various O2 conditions.