Soil carbon change (in mineral soils, organic soils and inorganic carbon)

Soil hosts the largest carbon pool in the terrestrial ecosystem, playing an essential role in the global carbon cycle and the regulation of climate change. Soil carbon is solid carbon stored in soils, existing in organic and inorganic forms. An important distinction between these two forms is that inorganic carbon has a much higher potential for permanence in soils than organic carbon. Soils are characterised as mineral or organic based on their organic matter content. Mineral soils form most of the world¿s cultivated land and may contain a trace of or up to 20 % organic matter. Organic soils are naturally rich in organic matter, principally due to vegetation and climate, and are distinguished from mineral soils by meeting specific criteria outlined in the IPCC guidelines for national GHG inventories (Drösler et al., 2014) and Food and Agriculture Organization (FAO) guidelines (FAO, 2006). These criteria include a thick organic horizon, a high organic carbon content, and the possibility of water saturation episodes.