期 刊 ：生态学报 2008年 28卷 5期 页码：1911~1911～1922
Keywords:desert ecosystem, soil respiration, temperature, soil moisture, Q10,
摘 要 ：采用LI-8100土壤碳通量测量系统测定了准噶尔盆地高（B）、低（A）两个盖度级3个典型荒漠植物群落梭梭、盐穗木、假木贼的土壤呼吸速率，比较分析了各样地土壤呼吸的变化特征及水热因子对荒漠土壤呼吸特征的可能影响。结果表明：生长季，土壤呼吸速率存在明显的日变化和季节变化规律，不同盖度和群落类型的荒漠土壤呼吸速率变化形式基本相同。日变化格局最高值出现在12：00~14：00，最低值在8：00或20：00；夏季各月（6、7、8月份）土壤呼吸速率高于秋季月份（9、10月份），春季（5月份）最低。高盖度梭梭群落样地日平均土壤呼吸速率与其他样地存在显著差异。各样地土壤呼吸速率与地表温度呈不同程度的正相关，而与土壤温度的相关性较弱；高盖度盐穗木样地（土壤湿度最高）、梭梭样地（土壤湿度最低）土壤呼吸速率与土壤湿度呈显著负相关。地表温度-土壤湿度的多变量模型能在更大空间尺度解释荒漠土壤呼吸速率时间变化的61.9%。样地间土壤呼吸速率的差异可能主要受土壤湿度影响。高、低盖度的梭梭、盐穗木和假木贼群落的Q10值分别为1.34、1.3、1.65、158、117和1.31，平均值1.39。
Abstract:Soil respiration is one of the ecosystem processes most sensitive to climate change, but is less studied in desert ecosystems. The spatial and temporal changes in soil surface CO2 efflux, the major CO2 source to the atmosphere from terrestrial ecosystems, directly influence the local and regional carbon budgets. In this study, we measured soil respiration and associated biophysical factors by using an automated CO2 efflux system (LI-COR 8100), and examined the effects of soil temperature and moisture on the rate of soil respiration for three desert communities (H. ammodendron, H. caspica and A. aphylla) at high (B) and low (A) coverage. It was found that soil respiration rate showed obvious diurnal and seasonal patterns during the growing season of plants, which were consistent across different communities and under different coverage. In the daytime, the maximum rate of soil respiration occurred between 12:00-14:00, the minimum around 8:00 or 20:00. The soil respiration rate was high in the summer (June, July and August), followed by the fall (September and October) and the spring (May). The difference in daily mean soil respiration between H. ammodendron B site and other community types and sites was significant from May through to October. The soil respiration correlated positively with soil surface temperature, with the degree of correlations apparently differing among the six sites. There were significant and negative correlations between soil respiration and soil moisture in H. ammodendron B and H. caspica B sites, which represented the driest and wettest sites, respectively. A multi-variable model about soil surface temperature and soil moisture could explain 61.9% of temporal variation in soil CO2 efflux at a larger scale. The Q10 values for H. ammodendron A、B, H. caspica A、B and A. aphylla A、B sites were 1.3、1.34、1.58、1.65、1.31 and 1.17, respectively, with an average of 1.39.
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