摘要 : Abstract Increased occurrence of heat wave events is an aspect of extreme climate change that may influence soil carbon (C) dynamics and greenhouse gas (GHG) emissions. However, heat wave events have rarely been studied; furthermo... 展开 Abstract Increased occurrence of heat wave events is an aspect of extreme climate change that may influence soil carbon (C) dynamics and greenhouse gas (GHG) emissions. However, heat wave events have rarely been studied; furthermore, their effects on C dynamics and GHG emissions in soils in agroforestry systems have not been studied. We conducted a laboratory incubation experiment to investigate the effect of simulated heat wave events and their frequencies on CO2 and N2O emissions, as well as soil labile C, in two land-use types in a common agroforestry system of western Canada. Both two- and three-time heat wave events increased CO2 and N2O emissions in both cropland and forest soils compared with the control (P?<?0.01), but there was no difference between two- and three-time heat wave events. Furthermore, cumulative emissions (both CO2 and N2O emissions) increased with greater heat wave frequency, but the effect diminished with each successive heat wave event. Emissions of CO2 and N2O were higher from the forest than cropland soils during heat wave events (P?<?0.01). Soil labile C (hot water extractable organic C and microbial biomass C) was higher in forest than in cropland soils (P?<?0.001) and did not respond to the heat wave treatment, but showed a declining trend with an increasing heat wave frequency. Our findings suggest that heat wave events increase soil CO2 and N2O emissions in the studied soils collected from an agroforestry system and may have a positive feedback mechanism to climate change. Increased GHG emissions from both cropland and forest soils should be considered when evaluating heat wave impacts on soil C sequestration, in addition to their commonly studied effect on ecosystem productivity. 收起