摘要：The roles of substrate availability and quality in determining temperature sensitivity ( Q 10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q 10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q 10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q 10 of the organic layer was 0.22–0.71 (absolute difference) higher than Q 10 of the mineral soil. Q 10 in both the organic layer (2.5–3.4) and the mineral soil (2.1–2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q 10 over incubation time in both layers suggested that Q 10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q 10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming.
