Soil Fractions Affect on Soil Organic Carbon Stock in the Coastal Land of Aceh Utara Regency, Indonesia

Soil organic carbon stocks (SOCs) play a critical role in supporting soil quality and ecosystem functions. Information on SOCs content in coastal lands is scanty and the types of clay minerals and soil fraction size that affect SOCs are still debated. We evaluated the SOCs content and identified the mineral type and soil fraction affecting the SOCs on coastal land.

Soil samples were collected from each layer of nine different soil profiles in three subdistricts: Seunuddon (SD), Lapang (LP) and Dewantara (DT) in Aceh Utara Regency of Indonesia. The soil profiles were taken from different distances (300, 900 and 1500 m from the shoreline-d.f.s).

The results revealed that SOCs possessed by each soil layer of coastal land in Aceh Utara varied between 0.64 to 43.45 MgC ha^-1. The highest to lowest average total of SOCs content for the location is SD>DT>LP, while for the position, the distance to the shoreline is 900 m>1500 m>300 m. Clay minerals such as labradorite, smectite, vermiculite and chlorite positively increase the SOCs content. Very fine sand is a size of the soil fraction that affects the increase in the levels of SOCs in coastal land.