Digital mapping and soil carbon stock distribution on various landuse of tropical peatland in Pesisir Selatan, West Sumatra

Indonesia has the largest tropical peatlands in the world covered an area of 14.91 million ha. Peatlands play an important role in global carbon sequestration. This study aimed to: a] map the peatland in Pesisir Selatan, Sumatra Barat calculate the soil carbon stock in the peatlands on various land use and peat thickness and c] identify the relationship of soil characteristics to the soil carbon. We investigated thirty soil samples in Pesisir Selatan. The land-use types on peatland in Pesisir Selatan consisted of forest [GH], shrub [GS], oil palm plantations [GPs], annual cropland[GLp], and bareland [GLp]. The results showed that the total area of peatlands in Pesisir Selatan is 78,998.74 ha, while the total amount of soil carbon stocks is 244 million tonnes, and the sequence follows GPs > GS > GH > GT > GLp. The average value of soil carbon stock is 3,090.89 per ha, the sequence follows GH > GS > GT > GPs > GLp. Hence, the average amount of soil carbon stock based on depth is 8,529 tons for peat depth > 600cm, 4,082 tons for peat depth 300-600 cm, and 525 tons for peat depth 0-300 cm. Differences in average values of soil carbon stock per ha are highly influenced by the differences in peat thickness. The dynamics of total carbon show a higher its content in the subsurface layer rather than in the surface layer. The soil carbon is linearly correlated with water content and it is inversely proportional to bulk density.