Identification of potential land use for carbon stock enhancement in SOC-deficient Alfisols of the sub-humid sub-tropics

Assessment of soil organic carbon (SOC) stock and identification of the factors influencing its spatial variation are crucial for adopting appropriate mitigation and adaptation strategies under changing climatic conditions. The present study aims to measure SOC content and stock and identify the factors contributing to SOC variation in India’s sub-tropical, dry sub-humid Eastern Plateau Region (EPR). It also aims to recognize the potential land uses for enhancing the C stock in the region. Soil samples were collected from two soil depth layers—0 to 10 cm and 10 to 20 cm, from locations under different soil type, land use, and topographic conditions. The Walkley-Black method was used to determine the SOC content of the samples. Ordinary kriging based on an exponential semi-variogram model was employed to analyze the spatial variability of SOC concentration and its relationship with the sampling strata. The study shows that the topsoil variation in SOC depended mainly on the land use type and the corresponding soil properties viz. pH and texture. Cultivated areas, especially those of the lowland, recorded higher SOC than other land use classes. The findings of the present study are useful for defining agricultural management practices and carbon sequestration strategies for the region in the context of climate change.