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

By the method of infrared CO2 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 x m(-2) x 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 253.36-357.05 g C x m(-2) x a(-1) and 538.69-703.82 g C x m(-2) x a(-1), respectively, and had the same variation trend as the annual soil respiration flux. The Q10 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 Q10 value was decreased with increasing restoration year, and was obviously higher in non-growth season than in growth season.