Soil Carbon Stock and Quality Indicators as Influenced by Land Use Systems and Soil Depths in Rainfed Areas of the Northwestern Himalayas, India

ABSTRACT This study assessed the effects of land use change on the soil carbon stock and soil quality indicators (SQIs) in Shivalik rainfed areas of the northwestern Himalayas. The values of soil pH, electrical conductivity and soil organic carbon (SOC) were highest in the forestland system, whereas the soil cation exchange capacity (CEC) was highest in the cultivated system. Among the carbon pools, SOC, total soil carbon, total organic carbon and inorganic carbon in the soil varied from 0.43%–0.71%, 1.47%–1.91%, 1.03%–1.35% and 0.44%–0.58%, respectively. The values of the soil carbon stock varied from 15.2–26.8, 42.1–55.5, 18.0–23.9 and 60.3–78.5 mg ha −1 for the soil organic stock, total organic carbon stock, inorganic carbon stock and total soil carbon stock, respectively. The soil pH and soil CEC increased with soil depth, whereas the electrical conductivity and SOC decreased with soil depth. Among the land use systems, the value of the soil quality index was highest in the forestry system, followed by the horticultural, agroforestry and agricultural systems. The surface layer (0–15 cm) presented the maximum value of the soil quality index and the lowest value at the 30–60 cm depth. Among the SQIs, SOC, soil pH, the cation exchange capacity and available potassium and soil inorganic carbon reflected the best SQIs, with contributions of 56%, 23%, 12%, 5% and 4%, respectively. These indicators can play vital roles in the improvement, maintenance and restoration of soil quality and resilience under different rainfed land use systems in the northwestern Himalayas, India.