Short-term effects of aboveground litter exclusion and addition on soil respiration in a schima superba forest in Zhejiang Province, eastern China

Litter as one of the major carbon (C) source of soil respiration may affect the soil respiration via its quantity and quality. In order to examine the quantitative differences of soil respiration rate, soil temperature and soil moisture induced by litter exclusion and addition, a litter manipulation experiment with litter exclusion and addition was conducted in Schima superba forest in Tiantong Forest Ecosystem, Zhejiang Province, China from February 2011 to May 2012. The treatments of litter exclusion and addition had a significant effect on soil moisture, but no significant effect on soil temperature. Compared with the mean soil respiration rate in the control (2.52±0.29 jjimol •m^-2 • s^-1) , the soil respiration rate was significantly decreased by 25.32% by litter exclusion but not significantly affected by litter addition treatment. The soil respiration showed an obvious seasonal variability under all three litter treatments, with a marginally significant difference in wet season (P = 0.065), but no significant change in dry season. Meanwhile, soil respiration rates in wet season were much higher than that in dry season for the three litter treatments. A significant exponential correlation was found between the soil respiration rate and the soil temperature at 10 cm depth, which explained 80.1%-90.3% of seasonal variation of soil respiration rate under three litter treatments. The Q₁₀ values in the control, litter exclusion and litter addition treatments were 2.42, 2.48 and 2.24, respectively. There was no significant relationship between soil respiration rate and soil moisture under three litter treatments. The results indicated that the short-term effects of litter manipulation on soil respiration were dependent on seasonal changes, and litter played a great role in altering soil respiration and soil C cycle in forest ecosystems.