Soil carbon storage potential of different land use systems in upstream catchment area of Gobind Sagar reservoir, Himachal Pradesh

Four land use systems (agriculture, agroforests, forest and grassland) from the upstream Gobind Sagar reservoir in Bilaspur district of Himachal Pradesh were studied to analyse their effect on soil carbon status. Randomly distributed 25 sites were selected in 14 km distance from the reservoir to collect soil samples (0–30 cm soil depth) from selected system. Elevation of the study sites ranged from 542 to 1024 m asl. Forest system recorded lower soil pH (6.76±0.17) and EC (0.15±0.029), soil bulk density and higher organic carbon (%) in comparison to other systems. Sites closer to the reservoir showed lower soil bulk density (p<0.05) and higher organic carbon (p<0.01). Higher soil organic carbon (85.34t ha⁻¹) was recorded in forest; however, agroforests (56.25 t ha⁻¹) and grassland (55.24t ha⁻¹) systems were statistically comparable. Principal component analysis (PCA) was employed to see the relationship between different land use systems and soil physico-chemical properties. First component accounted for 36.6% variance and the highest positive loadings were found with organic carbon (%) followed by soil organic carbon (t ha) and sand (%). Contribution from second component to the total variance was 26.3% and the highest positive loadings were found with silt (%) followed by EC, pH and clay (%), whereas higher negative loading was found with sand (%).