Abstract: To reveal the impact of precipitation on soil respiration and ecosystem respiration in the desert steppe ecosystem on the northern slope of the Tianshan Mountains. This experiment took the desert steppe on the northern slope of Tianshan Mountain as the research object, and measured the characteristic changes of the soil respiration and ecosystem respiration of the desert steppe under three simulated precipitation treatments (CK, 5 mm, 18 mm, 28 mm). The results show that soil respiration and ecosystem respiration have obvious diurnal changes under different precipitation treatments. Compared with CK, the soil respiration under the three precipitation treatments (28 mm, 18 mm, 5 mm) increased significantly by 22.93%, 23.20%, and 12.07%, respectively. Compared with CK, the ecosystem respiration under the three precipitation treatments (28 mm, 18 mm, 5 mm) increased significantly by 216.81%, 153.27%, and 39.35%, respectively. Under different precipitation treatments, the soil respiration rate and ecosystem respiration rate showed a significant positive correlation with soil temperature. The relationship between soil respiration and soil water content in the desert steppe is quadratic, and the relationship between ecosystem respiration and soil water content is linear. Therefore, precipitation is the main factor affecting the soil respiration and ecosystem respiration of the desert steppe.

Key words: Desert steppe, Soil respiration, Ecosystem respiration, Precipitation

摘要： 为揭示降水对天山北坡荒漠草原土壤呼吸和生态系统呼吸的影响，本实验以天山北坡荒漠草原为研究对象，通过测定3种模拟降水处理（CK，5 mm，18 mm，28 mm）下荒漠草原土壤呼吸速率和生态系统呼吸速率的变化特征。结果表明：不同降水处理下土壤呼吸速率和生态系统呼吸速率有明显的日变化趋势；3种降水处理下（28 mm，18 mm，5 mm）土壤呼吸速率较CK显著增加了22.93%，23.20%，12.07%，生态系统呼吸速率较CK显著增加了216.81%，153.27%，39.35%；不同降水处理下土壤呼吸速率和生态系统呼吸速率与土壤温度均表现为显著正相关关系；荒漠草原土壤呼吸速率与土壤含水量呈二次函数关系，生态系统呼吸速率与土壤含水量呈线性关系。因此，降水是影响天山北坡荒漠草原土壤呼吸速率和生态系统呼吸速率的主要因素。

关键词: 荒漠草原, 土壤呼吸速率, 生态系统呼吸速率, 降水