Soil nutrients concentration along altitudinal gradients in Indian Western Himalaya

Altitude is a determining factor of vegetation composition, ecosystem properties and processes, and availability of soil nutrients. Present study examined soil nutrients at two depths i.e. 0-15 cm and 15-30 cm along altitudinal gradients (1800-4000 m asl) in the Indian western Himalaya. Results of the study reveals an increase in organic carbon (OC), total nitrogen (TN), and total potassium (TK) along an altitudinal gradient, indicating that low temperature limits the cycling of organic matter at high altitudes. A significant positive relationship of soil nutrient parameters with altitude was observed for moisture content, OC, TN, TK, C:N ratio; however, it was negatively significant for pH. All the soil nutrients were higher for 0-15 cm depth than 15-30 cm across the altitudinal gradients. The tree species richness decreased with the increasing altitude. TN, OC, and TK were found at maximum levels in a broad-leaved forest (i.e. Betula utilis) at 4000 m, followed by Pinus wallichiana (3600 m) and Abies pindrow (3000 m). This indicates that broad-leaved forests contributed strongly to carbon sink in the high-altitude region of the Himalaya. It is concluded that forest stand structures and abiotic factors govern soil nutrients concentrations along altitudinal gradient in the Himalayan region.