Differences in Soil Carbon and Nitrogen Across Contrasting Land-Use Systems in a Sub-Tropical Hilly Region, North-East India

This study examines the impact of land-use change on soil properties in a hilly sub-tropical region in North-east India. We collected soil samples from three depths from five dominant land-uses, namely, natural forests (NAF), current jhum (shifting cultivation) (CJ), jhum fallows (JF), homegardens (HG) and Acacia pennata plantations (AP) that were analysed for their carbon (C) and nitrogen (N) concentration and stocks. Our results indicated that soil properties were significantly influenced by both land-use and soil depth. The greatest C and N concentrations were found in NAF compared to JF, CJ, AP, and particularly HG, indicating that the least disturbed soils had the best soil quality. Notably, however, C and N stocks were not less under shifting cultivation (i.e. CJ or JF) compared to NAF, although they were less under AP and HG. This study reflected distinct differences in soil properties under land-use change, particularly more intensive land-uses such as plantations, ultimately leading to negative feedbacks between soil properties and land-use systems.