Objective Carbon sequestration in plants and soils plays a crucial role in the carbon cycle, contributing to the reduction of carbon dioxide levels and enhancing soil productivity. Identifying plant species with high carbon sequestration potential is essential for the restoration and maintenance of rangelands.

Methods This study examined carbon sequestration in various plant organs—roots, stems, and leaves—of two plant species: wild almond (Amygdalus scoparia) and Ephedra (Ephedra procera). In addition, soil characteristics and carbon sequestration levels were assessed by collecting soil samples from depths of 0–15 cm and 15–30 cm, both at the base of plants and in the inter-plant spaces. In this study, the first experiment comprised two factors: plant species (A. scoparia and E. procera) and plant organs (leaves, stems, and roots). The second experiment also had two factors. The first factor was three types of soil masses (collected at the bases of A. scoparia, E. procera, and the control), and the second factor was soil sampling depth (0–15 cm and 15–30 cm). The study was conducted in the Dolatabad region of Fars Province, Iran.

Results Soil beneath A. scoparia had higher levels of organic carbon, organic matter, and carbon sequestration than E. procera and control soils. Furthermore, the 0–15 cm depth showed greater levels of these factors than the 15–30 cm depth. As soil depth increased, organic carbon, organic matter, and carbon sequestration decreased, while soil acidity increased. However, soil moisture content did not significantly vary between the two depths. Soil type and depth had significant effects on electrical conductivity. The control soil exhibited a significantly higher electrical conductivity than E. procera and A. scoparia soils. Additionally, average values indicated that electrical conductivity was significantly greater at the soil surface. Notably, both depths of the control soil showed the highest conductivity among all treatments, with the control differing significantly from the other groups. High electrical conductivity in the soil may indicate high salinity levels. Soils beneath A. scoparia and E. procera showed significant differences in clay content between the two soil depths, with the 0–15 cm depth exhibiting the highest clay content among all treatments.

Conclusions A. scoparia is found to store significantly higher amounts of organic carbon and organic matter in its tissues than E. procera. The cultivation of A. scoparia is highly feasible due to its high tolerance to drought, whereas other water-dependent species may require extensive management if cultivated in vast areas of rangelands. Organic carbon plays a more significant role than organic matter in determining the extent of carbon sequestration in the soil. Soil texture, particularly clay content, emerges as one of the most influential factors in carbon sequestration.