Organic carbon stocks in mountain grassland soils of northwestern Kashmir Himalaya: spatial distribution and effects of altitude, plant diversity and land use

Abstract

Despite constituting important ecosystem of Kashmir Himalaya and being sensitive to climate change, data on soil organic carbon (SOC) in grasslands remain scarce. Present study was conducted in 20 grasslands that represent pasture and non-pasture types, with an aim to record SOC stocks at 5 sampling depths (0–10; 10–20; 20–30; 30–40 and 40–50cm), study its variation along altitude and elucidate how environmental factors affect this variation. SOC stocks exhibited high variability and ranged between 28.85 and 94.76 Mg C ha−1, with mean value of 54.52 Mg C ha−1, which was stored as 30.63, 22.98, 21.06, 14.89, and 10.41%, respectively at five depths. Differences in SOC stocks between pasture and non-pasture types were minor, with average stocks appearing slightly higher for pasture (59.69 ± 15.43 Mg C ha−1) than non-pasture (56.32 ± 17.01 Mg C ha−1). However non-pasture type had higher stocks particularly in upper soil layers. SOC exhibited negative relationship with soil depth and bulk density while increasing relationship with altitude, species richness and aboveground live and dead biomass was observed. On depth gradient, altitude affected subsurface (10–20cm) soils more distinctly than surface (0–10 cm) soils. Besides contributing baseline data, comparison of SOC provides possibility to determine management effects on SOC storage and consequently C sequestration.