青藏高原东缘亚高山针叶林人工恢复过程中的土壤呼吸特征

采用动态密闭气室红外CO₂分析法,对青藏高原东缘云杉人工林的土壤呼吸进行连续定位测定,并用挖壕沟法区分土壤自养呼吸和异养呼吸.结果表明:4种云杉林的土壤呼吸速率与土壤5 cm层温度有显著的正指数关系,与土壤含水量的相关性不显著.4种云杉林土壤呼吸年通量在792.08～1070.20 g C·m^-2·a^-1,大小依次为：天然云杉林＞22年生云杉人工林＞65年生云杉人工林＞35年生云杉人工林,随着人工林的恢复呈先降低后升高的趋势.在森林恢复过程中,人工云杉土壤自养和异养呼吸年通量均先减少后增加, 在253.36～357.05 g C·m^-2·a^-1和538.69～703.82 g C·m^-2·a^-1范围变化.22年生、35年生、65年生云杉人工林和天然云杉林非生长季 （2007-11-2008-03）和生长季（2008-04-2008-10）的Q₁₀值分别为：4.59、6.54、4.77、3.18和4.17、4.66、3.11、2.74.除22年生云杉人工林，Q₁₀值随云杉林的恢复更新而逐渐降低, 且非生长季节Q₁₀值均明显高于生长季节.

Characteristics of soil respiration in artificial restoration process of subalpine coniferous forest in eastern Qinghai-Tibet plateau

By the method of infrared CO2 determination in closed dynamic chamber system, the soil respiration in natural spruce forest, and 22-， 35-and 65-year old spruce plantations in eastern Qinghai-Tibet plateau was measured in situ, and the soil heterotrophic and autotrophic respiration was differentiated by entrenchment. In the four spruce forests, soil respiration rate had a significant positive exponential correlation with the soil temperature at depth 5 cm, but less correlation with the soil moisture content at the same depth. The annual soil respiration flux was 79208-107020 g C·m-2·a-1, and decreased in the order of natural spruce forest＞22-year old spruce plantation＞65-year old spruce plantation＞35-year old spruce plantation. The annual soil autotrophic and heterotrophic respiration fluxes were 25336〖KG-*2〗-〖KG-*7〗35705 g C·m-2·a-1 and 53869〖KG-*2〗-〖KG-*7〗70382 g C·m-2·a-1, respectively, and had the same variation trend as the annual soil respiration flux. The Q10 value of soil respiration in 22-, 35-, and 65-year old spruce plantations and in natural spruce forest in growth season (from Nov. 2007 to Mar. 2008) and non-growth season (from Apr. 2008 to Oct. 2008) were 459, 654, 477, and 318, and 417, 466, 311, and 274, respectively. Except that in 22-year old spruce plantation, the Q10 value was decreased with increasing restoration year, and was obviously higher in non-growth season than in growth season.