Assessing the impact of land use and land cover changes on soil properties and carbon sequestration in the upper Himalayan Region of Gilgit, Pakistan

Abstract

Soil plays a pivotal role in the global carbon cycle, serving as a principal carbon reservoir in terrestrial ecosystems. This study investigates the impact of land cover variations on soil properties and soil organic carbon stocks (SOCS) across a watershed. Statistical analyses indicate significant changes in soil organic carbon (SOC), bulk density (BD), electrical conductivity (EC), temperature, moisture, and pH influenced by land use, with pH changes not significant across depths. Forest lands exhibit the highest SOC levels (2.27 % in 0–20 cm layer) and SOCS (30.03 mg/ha in 0–20 cm layer), declining significantly with depth across all land types. Nitrate nitrogen (NO₃-N) indicates lower soil quality in arable and pasture lands compared to forests, while exchangeable potassium (Ex. K) is higher in forests (118.3 mg/kg) than arable (114.6 mg/kg) and pasture lands (102.1 mg/kg). Pearson correlation analysis shows a positive relationship between SOCS and SOC. Soil textures vary with forest soils being silt loam and arable/pasture lands being loam. Using ArcGIS 10, supervised classification shows that forests, arable lands, and pastures cover 9.0 %, 1.8 %, and 8.2 % respectively of the 6407.88-hectare watershed in 2023. These findings emphasize the impacts of land development, conversion, and intensive agriculture on SOC stocks and carbon sequestration processes, underscoring the need for effective soil management strategies by local stakeholders and governmental agencies to enhance SOCS.