Abstract: This study was conducted in different regions of sagebrush desert grassland on northern slopes of the Tianshan Mountains in Xinjiang Uygur Autonomous Region， and investigated the effects of grazing enclosure on soil aggregate stability. The composition and stability of soil aggregates in the 0-50 cm soil layer were determined based on the wet sieving method. The results showed that the soil aggregates in sagebrush desert grasslands were mainly>0.25mm， with a content greater than 57.5%， but the response of each soil layer to enclosure was not consistent among different plots. After enclosure， the content of 0.25-2 mm aggregates in the 0-5cm and 5-10 cm soil layers of the Manas plot significantly increased by 70.0% and 60.8%， respectively， while the 5-10 cm， 10-20 cm and 20-30 cm soil layers of the Qitai plot significantly increased by 23.2%， 51.6%， and 32.7%， respectively. As the depth of the soil layer increased， the stability of aggregates showed an increasing trend firstly and then decreased. The enclosed area was slightly lower than the control area， but the differences between different plots were not significant. The stability of soil aggregates was significantly correlated with the content of soil aggregates （P<0.01）， among which silt+clay and microaggregates were the dominant factors affecting the stability of soil aggregates. After enclosure， the regulatory effect of vegetation coverage on soil aggregate stability enhanced， while soil bulk density became weakened. In summary， soil aggregates in the sagebrush desert grassland in northern Xinjiang were mainly>0.25 mm aggregates， and the overall stability of soil aggregates did not change significantly after 4-11 years of enclosure.

Key words: Grazing enclosure, Sagebrush desert grassland, Stability of soil aggregates, Driving factors

摘要： 为探究封育对土壤团聚体稳定性的影响，以新疆天山北坡不同区域蒿类荒漠草地为对象，基于湿筛法测定0~50 cm土层土壤团聚体组成及稳定性。结果表明：蒿类荒漠草地土壤团聚体均以>0.25mm为主，含量均大于57.5%，但各样地各土层对封育响应并不一致。封育后玛纳斯样地0~5 cm和5~10 cm土层0.25~2 mm团聚体含量显著增加70.0%，60.8%，而奇台样地5~10 cm，10~20 cm和20~30 cm土层依次显著增加23.2%，51.6%，32.7%。随土层深度增加，团聚体稳定性呈先增后降趋势，且封育区略低于对照区，但各样地间差异不显著。土壤团聚体稳定性与土壤团聚体含量显著相关（P<0.01），其中粉土+粘土、微团聚体是影响土壤团聚体稳定性的主导因素，且封育后植被覆盖度对土壤团聚体稳定性的调控作用增强，而土壤容重则为减弱。综上，新疆北部蒿类荒漠草地土壤团聚体以>0.25 mm团聚体为主，且封育4~11年土壤团聚体稳定性总体变化不显著。

关键词: 封育, 蒿类荒漠草地, 土壤团聚体稳定性, 驱动因子