Changes in the organic carbon pool of abandoned soils in Russia (1990-2004)

The assessment of the changes in the organic carbon pool in the soils of the Russian Federation that occured in 1990-2004 was carried out using approximation, soil-geoinformation, and simulation approaches. As a result of te changes in the system of land use, after 1990, the organic carbon storages in the 0- to 20-cm-thick soil layer could be 196-319 Mt depending on the methodology of the calculation applied and taking into account the abandoned area of 14.8 million ha. As compared to the beginning of the 1990s, the organic matter stock in the former plow layer increased by 1.6-5.8%. The great scatter of the data is mainly related to the incertainty of the estimates of the area of arable soils not used any more in agriculture