Global Soil Organic Carbon Density in kg Carbon/m2 to 1 meter depth

Soil organic carbon is a general term for the total of all the different non-living organic compounds in the soil, it also excludes dead plants and animals. The organic carbon in the soil is used by plants for nourishment as they grow, and the plants themselves replenish the resource when they decay after they die.

Although it would seem that high densities of soil carbon would correspond to areas where vegetation thrives, this is not necessarily the case. For example, the regions of the world categorized as tropical rainforest typically have very low quality soils - not because the soils are bad, rather because the highly active vegetation on the surface has already extracted most of the nutrient from the soil. The regions of the world where soil carbon accumulates, are therefore regions where vegetation growth is generally slower - such as swamps, bogs, and wetlands.