Impact of landuse systems on soil organic carbon and its projection in northwestern India

The evaluation of the impact of landuse on soil organic carbon (SOC) is required to understand the long-term productivity and possible sustainability of a landuse system. The effect of landuse on SOC was studied in the Shaheed Bhagat Singh Nagar district of Punjab (India). Surface (0–15 cm) and subsurface (15–30 cm) soil samples were collected under different land uses (cropland, forest, scrubland, and plantation) using stratified random sampling. Soil samples were analyzed for soil texture, bulk density, pH, electrical conductivity, organic carbon, Olsen P (available P), NH₄OAc–extractable K (available K), and CaCl₂ extractable S (available S) using standard methods. Ordinary kriging was used to study the distribution of soil properties in different land uses. Soil organic carbon under future climate was simulated using Rothamsted carbon (RothC) model with current landuse and management practices. Organic carbon in surface and subsurface soils was in the order: Forest > scrubland > plantation > cropland. The content of organic carbon, available P, K, and S decreased with increasing soil depth. The simulated SOC content in cropland soils under future climate may reduce, and in soils under forest, plantation and scrubland may increase by the year 2100. These results suggest that the landuse system is one of the major factors affecting SOC stocks. The study of organic carbon in different landuses could help the famers and policy makers to take measures for increasing SOC stocks to mitigate the climate change and also for sustainable agriculture.