中文摘要：

利用LI一8100A土壤碳通量自动测量系统，于2013年7月和11月对西藏色季拉山两种最典型天然林分（急尖长苞冷杉和林芝云杉）的土壤呼吸进行了测定，分析了土壤水热因子对土壤昼夜呼吸速率的影响。结果表明：两种林分土壤昼夜呼吸速率日变化呈现单峰曲线，昼高夜低。高峰值出现的时间在午后14：00—16：00之间，最低值出现在凌晨4：00―6：00之间。急尖长苞冷杉、林芝云杉7月、11月土壤呼吸速率日变幅分别为1.64，0.75，1。22，0。11Iμmol／（m2·s）。夏季（7月）土壤呼吸速率平均值高于冬季（11月），急尖长苞冷杉群落土壤呼吸速率高于林芝云杉群落。急尖长苞冷杉夏季（7月）土壤昼夜呼吸速率差异极显著，而冬季差异不显著。昼夜间土壤呼吸速率之间的关系可以用以夜间呼吸速率为自变量构建的幂函数方程（7月）和三次曲线方程（11月）来描述。土壤昼夜呼吸速率与地表下5cm处土壤温度之间的关系可以用指数曲线方程来描述，与土壤水分之间的关系可以用三次曲线方程来进行描述。

英文摘要：

Soil respiration of two typical forests （ Abies georgei var. smithii and Picea likiangensis var. linzhiensis ） in Sygara Mountains was examined in July and September in 2013 by using L1-8100 automated CO2 flux system, soil temperature and soil water condition influencing soil respiration were analyzed. The results showed that ： the daily changes of SRR （ soil respiration rate） of these two forests presented as unimodal curve. The peak value appeared between 14： 00―16：00 in the afternoon,then the lowest value appeared between 4： 00―6：00 in the morning. The daily change extent of SRR of Abies georgei var. smithii, was 1.64 μmol/（ m2 s） in July, and 0.75 μmol/（ m2. s） in September while that of Picea likiangensis var. linzhiensis, was 1.22 μmol/（m2 ·s） in July, and 0.11 μmol/（m2s） in September. The average SRR in the summer was higher than that in the winter, and the SRR of Abies georgei var. smithii was higher than that of Picea likiangensis var. lirtzhiensis. Significant difference of the SRR of Abies georgei var. smithii was available between the day and night in summer, but those in winter were unavailable. The relationship of day and night SRR could be described by Power function equation and Cubic equation based on the night SRR. The relationship of SRR and soil temperature could be described by Exponential curve equation, and the relationship of SRR and soil water condition could be described by Cubic equation.