凋落物作为土壤呼吸的重要碳源,其输入的数量和质量将对土壤呼吸产生重要影响。自2011年2月—2012年5月,在浙江天童森林生态系统设置对照、去除和加倍凋落物处理,研究不同凋落物处理对木荷(Schima superba)林土壤呼吸速率、土壤温度和土壤含水量的影响。结果表明:去除和加倍凋落物对土壤温度的影响不显著,对土壤含水量的影响显著,相比对照的土壤呼吸速率2.52±0.29 μmol·m^-2·s^-1,去除凋落物使土壤呼吸速率显著降低了25.32%;而加倍凋落物处理与对照之间的土壤呼吸速率无显著差异。不同凋落物处理下土壤呼吸均表现出明显的季节变化,凋落物处理在湿季对土壤呼吸速率的影响接近显著(P=0.065),在干季不显著,并且湿季的土壤呼吸速率显著高于干季。不同凋落物处理的土壤呼吸速率与土壤温度均呈显著相关,土壤温度解释了土壤呼吸速率变异程度的80.1%~90.3%,Q10值分别为2.42、2.48和2.24;而土壤呼吸速率与土壤含水量之间的相关性不显著。研究结果表明,短期凋落物处理对土壤呼吸产生了影响,并且这种影响因季节差异而不同,证明了凋落物对于改变森林生态系统土壤呼吸和碳循环具有重要作用。
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 μmol·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 shortterm 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.