Organic carbon in Icelandic Andosols: geographical variation and impact of erosion

The extensive soil erosion in Iceland during the past millennium has led to an irregular distribution of soil organic carbon (SOC). Intact and fully vegetated areas typically have Andosols with large amounts of organic carbon, whereas eroded areas are barren deserts with little organic carbon. We estimate the amount of organic carbon eroded during the past millennium is 120–500×106 t, whereas the total organic carbon in Icelandic soils is 2.1×109 t. Approximately half of the eroded organic carbon (60–250×106 t C) has been oxidized and released to the atmosphere. Current ongoing losses of SOC are estimated to be 50–100×103 t C yr−1. We also consider procedures for sequestering carbon to restore the carbon dynamics of denuded areas.