Abstract
As an important component of terrestrial ecosystem carbon cycle, soil respiration is a hot topic in the studies of carbon cycle. The temperature sensitivity (Q10) of soil respiration is a critical index to estimate the effects of global warming on soil respiration. Understanding Q10 of different vegetation types is of important significance for assessing the carbon budget of forest ecosystems. We examined soil respiration and its temperature sensitivity in three typical forests (Pinus tabuliformis, Platycladus orientalis, and Quercus variabilis) in the Beijing mountainous area by measuring the soil physical and chemical properties, soil temperature, soil moisture, and soil respiration rate (Rs) during the growing season. The results showed that Rs of three typical vegetation types showed a similar trend with changes of soil temperature and humidity, which showed a unimodal pattern, with minimum value (0.45 μmol·m-2·s-1) in early April and maximum value (3.95 μmol·m-2·s-1) in early July. There were significant differences in Rs and Q10 values among the three vegetation types. Soil temperature and humidity were the important factors affecting soil respiration, together they could explain the seasonal variation of soil respiration rate from 48.1% to 56.7%. The range of Q10 value was between 2.05 and 3.19. There was a significant negative correlation between soil organic carbon content and Q10 under each vegetation type (R2>0.9). Vegetation type, elevation, and soil organic carbon content were important drivers for the variation of Q10.
Published Version
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