University of Sistan and Baluchestan Journal of Natural Environmental Hazards 2676-4377 Articles in Press 2025 09 27 Investigation of the Effect of Livestock Grazing Intensity on Soil Carbon and Nitrogen Sequestration and Environmental Implications in the Sarsaru Rangelands, Khash Investigation of the Effect of Livestock Grazing Intensity on Soil Carbon and Nitrogen Sequestration and Environmental Implications in the Sarsaru Rangelands, Khash 1 1 9418 10.22111/jneh.2025.52908.2134 FA Morteza Saberi Associate Professor, Rangeland and Watershed Management Department, Faculty of Water and Soil, University of Zabol, Zabol, Iran. Rasool Khatibi Assistant Professor, Rangeland and Watershed Management Department, Faculty of Water and Soil, University of Zabol, Zabol, Iran. Vahid Karimian Assistant Professor, Nature Engineering Department, Faculty of Natural Resources, Yasouj University, Yasouj, Iran Journal Article 2025 08 11 Soil carbon sequestration has become increasingly important as one of the most effective strategies for reducing greenhouse gas emissions and mitigating climate change. This study aimed to investigate the effects of livestock grazing intensity on soil carbon and nitrogen storage in the Sarsaru rangelands of Khash County, which are characterized by arid and unique ecological conditions. Soil samples were collected under three treatments: no grazing, light grazing, and heavy grazing, at three depths (0–30, 30–60, and 60–90 cm). The measured parameters included pH, electrical conductivity, bulk density, organic carbon, total nitrogen, carbon storage, and nitrogen storage. The results indicated that carbon and nitrogen storage in the ungrazed area were significantly higher than in areas under light and heavy grazing. Specifically, in the 0–30 cm layer, carbon storage was 11.35, 8.73, and 5.34 t/ha, and nitrogen storage was 1.87, 1.69, and 1.01 t/ha under no, light, and heavy grazing, respectively. Heavy grazing caused the greatest reduction in carbon and nitrogen stocks at all depths, whereas light grazing had a lesser effect. Additionally, bulk density increased with depth in all sites (from 1.39 to 1.62 g/cm³), and electrical conductivity increased significantly in deeper layers, particularly under heavy grazing. These changes reflect the impact of livestock grazing on soil structure and quality, potentially reducing microbial activity and carbon and nitrogen fixation processes. Therefore, optimal management of grazing intensity is essential to maintain soil carbon and nitrogen stocks, enhance fertility, and ensure the stability of rangeland ecosystems in drylands. The findings highlight the importance of reducing grazing pressure and preserving vegetation cover to prevent soil degradation and control erosion. Such practices improve soil biological function and increase the resilience of rangelands to climatic stress. Soil carbon sequestration has become increasingly important as one of the most effective strategies for reducing greenhouse gas emissions and mitigating climate change. This study aimed to investigate the effects of livestock grazing intensity on soil carbon and nitrogen storage in the Sarsaru rangelands of Khash County, which are characterized by arid and unique ecological conditions. Soil samples were collected under three treatments: no grazing, light grazing, and heavy grazing, at three depths (0–30, 30–60, and 60–90 cm). The measured parameters included pH, electrical conductivity, bulk density, organic carbon, total nitrogen, carbon storage, and nitrogen storage. The results indicated that carbon and nitrogen storage in the ungrazed area were significantly higher than in areas under light and heavy grazing. Specifically, in the 0–30 cm layer, carbon storage was 11.35, 8.73, and 5.34 t/ha, and nitrogen storage was 1.87, 1.69, and 1.01 t/ha under no, light, and heavy grazing, respectively. Heavy grazing caused the greatest reduction in carbon and nitrogen stocks at all depths, whereas light grazing had a lesser effect. Additionally, bulk density increased with depth in all sites (from 1.39 to 1.62 g/cm³), and electrical conductivity increased significantly in deeper layers, particularly under heavy grazing. These changes reflect the impact of livestock grazing on soil structure and quality, potentially reducing microbial activity and carbon and nitrogen fixation processes. Therefore, optimal management of grazing intensity is essential to maintain soil carbon and nitrogen stocks, enhance fertility, and ensure the stability of rangeland ecosystems in drylands. The findings highlight the importance of reducing grazing pressure and preserving vegetation cover to prevent soil degradation and control erosion. Such practices improve soil biological function and increase the resilience of rangelands to climatic stress. https://jneh.usb.ac.ir/article_9418_db4aa64b9ee34601bfe5662a140f801b.pdf