Updated estimate of carbon balance on Russian territory

Abstract

The land use system in Russia changed considerably after 1990: 30.2 million ha of croplands were abandoned. Based on the own field investigations that were carried out in abandoned lands of different age (Luvic Phaeozems, deciduous forest zone; Moscow region, 54.50N, 37.37E), it has been shown that after 4.5 yr of abandonment, the former croplands acted as a stable sink of CO₂. The net ecosystem production (NEP) in the post-agrogenic ecosystems averaged 245 ) 73g C m^-2 yr^-1 for the first 15 yr after land use change that corresponds to an estimated 74 ) 22 Tg C yr^-1 for the total area of abandoned lands in Russian Federation. Currently, the Russian territory acts as an absolute sink of atmospheric CO₂ at a rate about 0.90 Pg C yr^-1. Using three different approaches, it was demonstrated that after 1990, the carbon sequestration in Russian soils (0.20 cm layer) has averaged 34 ) 2.2 Tg C yr^-1. This soil C forms net biome production (NBP) where carbon lifetime is much longer than in eKyoto forestsf. Thus, the post-agrogenic ecosystems in Russia provide with the additional CO₂ sink in NEP and NBP that could annually compensate about 25% of the current fossil fuel emissions in the Russian Federation.