亚热带樟树人工林土壤呼吸对凋落物处理的响应

Response of soil respiration to litter treatment of Cinnamomum camphora in subtropical aera

2011年9月到2012年8月,选取湖南省长沙市湖南省森林植物园樟树Cinnamomum camphora人工林作为试验样地,设置添加凋落物(DL)、去除凋落物(RL)和对照(CK)3种处理,对不同处理下土壤呼吸速率进行12月的连续观测。研究结果表明:樟树人工林不同处理下土壤呼吸呈显著的季节动态,均呈单峰曲线。添加凋落物处理下(DL),土壤呼吸的年均值为2.816,去除凋落物处理下,土壤呼吸的年均值为1.943,与对照的2.534相比分别高14.33%和低23.01%。樟树人工林凋落物处理下土壤呼吸速率与5 cm土壤温度呈极显著线性相关(P<0.01),与5 cm土壤湿度相关性不显著(P>0.05)。樟树人工林添加和去除凋落物处理下土壤呼吸Q10值分别为2.04、2.02,均高于对照的1.87。由此可见凋落物对森林CO2通量有重要影响。

From Sept. 2011 to August 2012, the Cinnamomum camphora plantation grown in Hunan Forest Botanical Garden, which located in southern suburbs of Changsha city, were selected as the experimental sample plots. Three treatments such as litter addition（DL）, litter exclusion（RL） and control （CK） were set. The soil respiratory rate values of different treatments were continuously observed for 12 months. The results show that under different treatments the soil respiration of C. camphora plantation appeared significant seasonal dynamics, and they all presented single peak curves; The annual average value of the soil respiration with litters addition treatment was 2.816, and the annual average value of the soil respiration with litters exclusion treatment was 1.943, which were 14.33% and 23.01% higher than that of the control, respectively; The soil respiration rate and soil temperature in 5 cm depth of C. camphora plantation showed a significant linear correlation（P 〈 0.01）, and had no significant correlation with soil moisture （P 〉0.05）; The Q10 values of C. camphora plantation under DL and RL treatments was 2.04 and 2.02, respectively, which were all higher than the value of CK（1.87）. Thus, the litters had important influence on forest CO2 flux.