Land management has a decisive effect on the physical and chemical properties of soil. However, there is limited data available on how the alteration of land use impacts organic matter and soil quality in Sulaymaniyah, the Kurdistan region of Iraq. This study was conducted to investigate the soil aggregation condition and soil organic carbon (OC) under four different land uses including forest, deciduous trees, cropland, and native grassland in Sulaymaniyah. The findings indicated that the mass of heavy fraction was greater in the land uses of forest and deciduous trees compared to cropland and native grassland. In addition, the concentration of free light fraction was lower in native grassland than in other land uses. The forest and deciduous trees land uses exhibited elevated concentrations of OC, which helped to protect the soil through both chemical and physical processes. The forest had the highest values of aggregate mass and OC content associated with macro-aggregates, while the native grassland had the lowest values. The forest soil was mainly composed of macro-aggregates. In the forest soil, macro-aggregates associated OC accounted for 59% of the organic carbon content, whereas in the grassland soil, most of the OC content was found in the micro-aggregates. Overall, the results suggested that ecosystems characterized by a consistent vegetation cover, such as forests, exhibited improved development of macro-aggregates and a rise in the associated OC content as a result of returning plant residues into the soil.