【摘要】 干旱区是对气候变化较敏感的特殊而重要的地理单元,研究干旱区的土壤呼吸及其影响因素对于深入理解全球碳循环具有极其重要的意义。根据2006年5～10月对准噶尔盆地西北缘梭梭、假木贼、盐穗木等三种主要荒漠植物群落的土壤呼吸速率及主要环境因子的逐月监测资料,分析了梭梭、假木贼、盐穗木等群落土壤呼吸速率的差异及对温度、土壤含水量变化的响应。结果表明:这三种荒漠植物群落土壤呼吸速率日变化随温度升高而上升,日动态均呈单峰型特征,最高值皆出现在14:00,最低值出现在早晨8:00,土壤呼吸速率最大值出现时间提前于气温最高值出现的时间。三种植物群落土壤呼吸速率的月变化特征具有一致性,呈现单峰曲线,与近地面气温的变化趋势基本一致。在植物生长季,按平均土壤CO₂释放速率、季节变幅大小排序为:梭梭群落>假木贼群落>盐穗木群落,群落间土壤呼吸速率差异显著,群落内不同季节土壤呼吸速率差异不显著。假木贼和盐穗木群落土壤呼吸速率日变化与近地面气温、地表温度和5 cm土壤温度具有极显著相关性,与10 cm土壤温度具有显著相关性,拟和关系均符合三项式函数关系（P<0.01）。梭梭和盐穗木群落与20～30 cm、30～40 cm层土壤含水量呈显著相关水平。更多还原

【Abstract】 The arid area is the special and important geography unit,which is more sensitive to the climatic change.Study of the soil respiration and its affecting factors in the arid area for in-depth understanding the global carbon cycle has the great significance.The soil respiration rate during the plant growing period（from May to October in 2006） and major environmental factor were determined by means of a LI -8100 automated soil CO₂ flux system in the Haloxyon ammodendron,Anabasis sp,Halostachys Caspica communities of desert ecosystem in the northwest Junggar Basin.Based on the monthly monitoring data,we evaluated the difference in soil respiration rate and influence of temperature and soil moisture on soil respiration rate in the three desert communities.The results indicate that:soil respiration rate of three major desert communities had significant diurnal variation and seasonal dynamics, all of them was shown a single-peak curve.In the plant growth season,the soil respiration rate showed a similar diurnal variation and seasonal dynamics tendency with air temperature and soil surface temperature variation. Soil respiration increased congruously with increasing soil temperature,but the appearing time of maximum temperature was later than that of maximum respiration rate.Maximum rate of CO₂ emission appeared at 14:00 and minimum at 8:00 in the early morning.According to the mean soil respiration rate and seasonal amplitude during the plant growing season,its pattern was observed in order of Haloxyon ammodendron community>Anabasis sp community>Halostachys Caspica community.The soil respiration rate had significant difference between the different communities and was not significant within the same communities.Correlation analysis showed that soil respiration rate of Anabasis sp,Halostachys Caspica community was significantly correlated with air temperature,soil temperature at the surface,5cm and 10 cm depth.The relationship between soil respiration rate（Y） and air temperature （X） could be described as a cubic regression equation（P <0.01）.Soil water content was another important factor affecting soil respiration rate,but in this region,the relationship between soil respiration and soil moisture was poor.Correlation analysis showed that soil respiration rate was significantly correlated with 20-30 cm,30-40 cm’s soil moisture in the Haloxyon ammodendron,Halostachys Caspica communities and no distinct relationship was shown in the Anabasis sp community.更多还原