Effects of Experimental Drought on Soil CO₂ Efflux in a Larix Kaempferi Stand

초록

Climate models forecast more frequent and a longer period of drought events which may impact forest soil carbon dynamics, thereby altering the soil respiration (SR) rate. We examine the simulated drought effects on soil CO₂ effluxes from soil surface partitioning heterotrophic and autotrophic soil respiration sources. Three replicates of drought plots (6 x 6 m) were constructed with the same size of three control plots. We examined the relation between CO₂ and soil temperature and soil moisture, each being measured at a soil depth of 15 cm. We also compared which factor affected CO₂ efflux more under drought conditions. Total SR, autotrophic respiration (AR) and heterotrophic respiration (HR) were positively correlated with soil temperature (p < 0.05), and the relationships were stronger in roof plots than in control plots. Total SR, AR, and HR were negatively correlated only in roof plots, and the only HR showed a significant correlation (p < 0.05, r = -0.59). Soil respiration rates were more influenced by soil temperature than by soil moisture, and this relationship was more evident under drought conditions.

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