This study aimed to assess the soil factors affecting the amount of soil organic carbon storage and the development of a model to estimate carbon reserve using physical and chemical properties of soils in East Azerbaijan rangelands. Ninety two soil samples were collected randomly from various rangeland sites and their characteristics including their soil organic carbon contents were measured in the laboratory. Path analyses and stepwise regression were used to identify the most important factors affecting soil organic carbon content. Results revealed that soil saturated moisture, pH, silt, EC and clay have direct effects on soil organic carbon with path coefficients of 0.443, -0.244, 0.223, -0.204 and 0.175 respectively. Parameters such as bulk density, gravel, and total cation exchange capacity have indirect effects on soil organic matter contents with sum path coefficient of -0.349. Soil physical properties had more influence (with path coefficient of 0.55) on soil organic carbon compared to the chemical characteristics (with path coefficient of -0.09). Stepwise regressions revealed that factors such as clay, silt, moisture maintenance capacity, pH and electrical conductivity represent 57 % of variation in soil organic carbon content. Conserving soil fine particles from erosion and preventing soil salinization can enhance soil organic reserves and maintain rangelands functionality.
 

Keywords: Rangelands, Path analysis model, Stepwise regression, Carbon storage, Soil characteristics.

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