Soil Organic Carbon Stock in Natural and Human Impacted Ecosystems of Senapati District, Manipur

The present study was carried out to estimate the soil organic carbon stocks (SOC) under different land uses of Senapati district, Manipur. The natural Undisturbed mixed Oak Forest (UOF) which was dominated by Quercus serrata and co-dominated by Lyonia ovalifolia, Disturbed mixed oak forest (DOF) dominated by Quercus serrata and co-dominated by Quercus griffithii, Pinus kesiya Plantation Forest (PPF) and Orchard Plantation Forest (OPF) dominated by Mangifera indica and co-dominated by Prunus domestica with their corresponding GPS coordinates located between 25 12.067 N to 2512.145 N and 9359.915E to 9402.296 E and at the elevation of 1146-1254 m msl. Soil organic carbon stock was estimated upto 30 cm soil depth and maximum SOC stock was found in UOF followed by DOF, OPF and least SOC stock was recorded under the PPF with mean SOC stock value 55.46 tha-1, 53.34 t ha-1, 53.26t ha-1 and 42.72 t ha-1 respectively. In all the different land uses the percentage SOC content decreased with increased in soil depths. The depth wise distribution of the estimated SOC stock under different ecosystems showed highest amount in the surface soil layer (0-10 cm) than the subsurface soil layers. Soil layer 0-10 cm contributes 42.65 %, 41.14 %, 41.49 % and 39.985 % in UOF, DOF, PPF and OPF respectively. SOC showed negative correlation with soil bulk density and pH but positive correlation with soil temperature and moisture. The naturally occurring mixed oak forest sequesters more carbon in the soils than the pine plantation forest. On the other hand Orchard plantation also plays a potential role in capturing large amount of carbon into the soil. Thus our nding highlights the future strategy of protecting and conserving the existing Secondary mixed Oak forest and substituting Orchard plantation in place of large coniferous plantations in Senapati district, Manipur.