[目的] 探明不同林分类型对圪秋沟流域土壤碳库与土壤碳稳定性的影响，为探讨土壤固碳机理、优化圪秋沟流域土壤管理及人工林选育措施，实现圪秋沟流域土壤固碳减排和肥力提升提供理论依据。[方法] 于2013—2021年在内蒙古自治区鄂尔多斯市圪秋沟流域以8 a生的樟子松林、山桃林、油松林、杨树柠条混交林、油松侧柏混交林和沙棘山杏混交林及CK处理共7个样地为研究对象，测定不同林分类型在不同土层深度的土壤总有机碳(TOC)、惰性有机碳(ROC)、易氧化有机碳(EOC)和微生物量碳(MBC)含量以及土壤碳储量，研究其对土壤碳库的影响效果，探讨不同林分类型与土壤碳稳定性间的相互关系。[结果] 与CK处理相比，0—20 cm和20—40 cm土层土壤总有机碳、惰性有机碳、易氧化有机碳和微生物量碳含量以及土壤碳储量，增加了9.46%～51.24%，1.76%～44.89%，16.48%～44.26%和9.03%～64.84%以及10.61%～55.52%。[结论] 不同林分类型人工林的种植均能提高0—20 cm和20—40 cm土层土壤TOC，ROC，EOC和MBC含量以及土壤碳储量；土壤TOC，EOC，MBC含量和土壤碳储量整体上随着土层深度的增加而降低，ROC含量随着土层增加而增加；0—20 cm和20—40 cm土层各林分类型土壤碳库指数与CK处理相比均增加，樟子松林、山桃林、沙棘山杏混交林更有利于圪秋沟流域土壤“碳封存”。
[Objective] The effects of different stand types on soil carbon pools and soil carbon stability in the Geqiugou watershed in Ordos City of Inner Mongolia Autonomous Region were analyzed in order to provide a theoretical basis for determining the mechanism of soil carbon sequestration, optimizing soil management and plant breeding measures in the Geqiugou watershed, and realizing soil carbon sequestration emission reduction and fertility improvement in the Geqiugou watershed. [Methods] Eight-year-old plantations of Pinus sylvestris, Carga cathayensis, Pinus tabulaeformis, Poplar-Caragana mixed forest, Chinese pine and arborvitae mixed forest, sea buckthorn and mountain apricot mixed forest, and a control (CK) treatment were used as the research objects in the Geqiugou watershed from 2013 to 2021. The contents of total organic carbon (TOC), resistant organic carbon (ROC), easily oxidizable organic carbon (EOC), microbial biomass carbon (MBC), and soil carbon storage in different stand types at different soil depths were determined to study the effects of plantations on soil carbon pools, and to determine the relationship between different stand types and soil carbon stability. [Results] Compared with the CK treatment, the contents of TOC, ROC, EOC, MBC, and soil carbon storage in the 0—20 cm and 20—40 cm soil layers increased by 9.46%—51.24%, 1.76%—44.89%, 16.48%—44.26%, 9.03%—64.84%, and 10.61%—55.52%, respectively. [Conclusion] Plantations of different stand types can increase soil TOC, ROC, EOC, MBC contents and soil carbon storage in the 0—20 cm and 20—40 cm soil layers. The soil TOC, EOC, MBC contents and soil carbon storage decreased with increasing soil depth, and soil ROC content increased with soil layers. The soil carbon pool index for each stand type in the 0—20 cm and 20—40 cm soil layers was greater than that of the CK treatment. P. sylvestris, C. cathayensis, and mixed sea buckthorn and mountain apricot were more conducive to soil carbon sequestration in the Geqiugou watershed.