Carbon in Russian Soils

Soil carbon densities and pools have been estimated for Russia. The estimate was derived from the generalized version of the soil map of the country at the scale 1:2.5 million (Fridland, 1988), which has been designated a countrywide standard. At the pre-developed stage, the soils in Russia captured about 373 Pg of organic and 75 Pg of inorganic C in the 0–2.0 m layer. Organic C is intensively accumulated in the topsoil. Inorganic C tends to concentrate in deep soils and is of non-pedogenic origin. The mass of organic matter is captured in the tundra, pre-tundra, and the northern and middle taiga of Russia. Anthropogenic impacts have led to a loss of about 5 Pg of C in the 0–1.0 m layer, which is some 2% of the total C content in Russian soils. From this amount, the topsoil of cropland has lost 2.6 Pg (20% of the initial C content in soils), including 0.4 Pg caused by erosion. The deep soil (0.3–1.0 m) of cropland has lost 1 Pg. Some 0.5 Pg of C are removed from the topsoil (7%) and 0.6 Pg by the deep soil from pastures. Forest soils have roughly lost about 0.3 Pg of C due to the decline of C input into soils caused by various disturbances. The predicted climate warming is expected to enhance the C sequestration by soil in Russia.