Vertical distribution of soil properties and soil organic carbon in community managed forest of Siwalik Hill, Nepal

Abstract. Lamichhane U, Ghimire P. 2022. Vertical distribution of soil properties and soil organic carbon in community managed forest of Siwalik Hill, Nepal. Asian J For 6: 91-96. Nepal's Community Forestry (CF) approach is globally recognized as an innovative and successful approach to forest resource management. Shorea robusta Gaertn. is the dominant tree species of Nepal's forest which covers 19.28% of the total stem volume of the country's forest area. Soil represents a significant terrestrial Carbon (C) pool and can play a significant role in mitigating global warming. Therefore, analyzing soil physicochemical properties and Soil Organic Carbon (SOC) stock is essential because they are key parameters for evaluating land use management systems. The present study was conducted in the Durga Mai Community Forest (DMCF) of Makawanpur District, Nepal, to assess the vertical distribution of soil physicochemical properties and SOC stock. Soil samples within a 1 m profile in five depth layers (0-20 cm, 21-40 cm, 41-60 cm, 61-80cm, and 81-100 cm) were collected and analyzed for Bulk Density (BD), soil texture, soil pH, soil carbon content, Total Nitrogen (TN), Available Phosphorous (AP), Available Potassium (AK) and SOC stock. Sandy loam was the dominant soil textural class reported throughout the study area. Average BD, soil pH, TN, AP, and AK in the S. robusta forest's soil in 1 m soil profile depth were found to be 1.16 ±0.07 gmcm-3, 5.78 ±0.62, 0.14 ±0.04 %, 5.94 ±1.04 kgha-1, and 104.20 ±19.66 kgha-1, respectively. The results estimated 107.57 ±3.06 tha-1 of SOC stock in 1 m soil profile, with 0.93 ±0.21% average SOC content. Further, average TN, AP, and AK were found to be decreased with an increase in soil profile depths. Similarly, soil profile depths significantly affected SOC stock and soil properties like BD, soil pH, TN, AP, and AK.