Abstract: The soil respiration rate during the growing season of desert shrub grassland in the southern margin of Gu er ban tong gu te desert,junggar basin,xinjiang was measured by li-8100 open-circuit soil flux measurement system. The soil temperature and moisture of each layer showed obvious periodic variation with season,and the vertical gradient of soil temperature and moisture at different depths was obvious. Soil respiration in desert shrub grassland showed a "bimodal" curve in daytime. During the growing season,the soil respiration rate was higher in daytime than at night,and the soil respiration rate of grassland was about four times of that of bare land. At night,bare soil shows a process of carbon absorption. Soil respiration rate was negatively correlated with soil temperature and moisture in daytime,positively correlated with soil temperature and moisture at night. During the growing season,the influence of soil moisture conditions on soil respiration rate is greater in daytime,the influence of soil temperature and humidity at night on soil respiration process is less than that in daytime. This study provides a theoretical basis for clarifying the process of carbon budget in arid areas.

Key words: Desert scrub grassland, Soil temperature, Soil moisture, Soil respiration rate

摘要： 本研究利用Li-8100开路式土壤通量测量系统对新疆准噶尔盆地古尔班通古特沙漠南缘荒漠灌丛草地生长季土壤呼吸速率进行了观测，分析了该地土壤呼吸特征及其与土壤温、湿度的关系。研究表明各层土壤温、湿度随着季节表现出明显的周期性变化特征，不同深度土壤温、湿度垂直梯度明显。荒漠灌丛草地土壤呼吸白天呈"双峰型"曲线；生长季土壤呼吸速率白天高于夜晚，草地土壤呼吸速率约为裸地的4倍；裸地夜间土壤表现为碳吸收过程。白天土壤呼吸速率与土壤温、湿度呈负相关关系，夜间为正相关关系；生长季白天土壤水分条件对土壤呼吸速率的影响更大，而夜间土壤温、湿度对土壤呼吸过程的影响均小于白天。该研究为明确干旱区碳收支过程提供一定的理论依据。

关键词: 荒漠灌丛草地, 土壤温度, 土壤湿度, 土壤呼吸速率