Abstract: From January 2009 to December 2009, the soil respiration in the Citrus reticulata and Castanea henryi orchards in Wanmulin Nature Reserve was measured with Li-8100, aimed to characterize the dynamic changes of the soil respiration and its relationships with soil temperature and moisture in the two orchards. The monthly variation of the soil respiration in the orchards was single-peaked, with the peak appeared in July (3.76 μmol·m^-2·s^-1) and August (2.69 μmol·m^-2·s^-1). Soil temperature was the main factor affecting the soil respiration, and explained 73%-86% of the monthly variation of soil respiration. The average annual soil respiration rate was significantly higher in Citrus reticulataorchard than in Castanea henryi orchard, with the mean value being 2.68 and
1.55 μmol·m^-2·s^-1, respectively. There was a significant positive correlation between the soil respiration rate and soil moisture content in Castanea henryi orchard, but less correlation in Citrus reticulataorchard. The Q₁₀ value of the soil respiration in Citrus reticulata and Castanea henryi orchards was 1.58 and 1.75, and the annual CO₂ flux was 10.01 and 5.77 t C·hm^-2·a^-1, respectively.