Carbon sequestration due to the abandonment of agriculture in the former USSR since 1990

Abstract

International audienceThe end of the Soviet Union and the collapse of its agricultural structures in the early 1990s has induced the abandonment of a large croplands area, which have been recovered by herbaceous plants. This widespread unintended and abrupt land use change took place over 200,000 km(2), a large enough scale to impact the continental and global carbon budgets. The goal of this study is to estimate the net biome productivity (NBP) of the abandoned croplands and to assess the soil C storage dynamics due to recent land conversion. The soil C balance and its input (net primary productivity) and output (heterotrophic respiration) fluxes is simulated in a spatially explicit manner with the process-driven natural vegetation/crop model Organizing Carbon and Hydrology in Dynamic Ecosystems-Supra-Thermal Ion Composion Spectrometer prescribed with successive area changes of abandoned croplands during the 1990s. We estimate that regional agricultural abandonment is responsible of a cumulated carbon sink over 1991 2000 of 373 gC m(-2), or 64 TgC over the domain considered, which defines a mean annual C sink of 46.7 g C m(-2) a(-1). Agricultural practices during the former cultivation phase determine a legacy on the C sink following abandonment, which impacts by +37% to -25% according to the practice considered (no tillage, no fertilization, and export of some crop residues). We conclude that futures studies of this regional change in the C cycle should better consider management information in order to refine the NBP estimate

Large-scale carbon sequestration in post-agrogenic ecosystems in Russia and Kazakhstan

“…Therefore, their C stocks are a major contribution to the global one (Kurganova et al, 2010a;Kurganova and Kudeayrov, 2012). Over the last decade, several studies (Kurganova et al, 2010a(Kurganova et al, , 2014Larionova et al, 2003a;Romanovskaya, 2008;Schierhorn et al, 2013;Vuichard et al, 2008) were aimed to estimate the total C sequestered in Russian soils due to the croplands abandonment. The application of various approaches and discrepancy within areas of abandoned lands and rates of C sequestration resulted in the significant variability of previous estimations of total changes in C stocks in Russian soils after LUC: from 0.47 to 1.29 Mg C ha −1 yr −1 .…”

An estimate of the terrestrial carbon budget of Russia using inventory-based, eddy covariance and inversion methods

“…This was by far the largest land use change (LUC) of the 20th century in the Northern Hemisphere (Lyuri et al, 2010), of which the implications for shifts in C budgets and pools of the territory of the Russian Federation still need to be confirmed. Current estimates of C accumulation in grassland soils after abandonment are uncertain, with estimates of the biosphere to atmosphere flux from −8 Tg C yr −1 (Vuichard, et al, 2008) to −45 Tg C yr −1 (Kurganova et al, 2010a,b), mostly in European Russia. In Kazakhstan, where cropland area decreased by 40 % between 1990 and 1996 due to abandonment, a C sink could exist as well but has not been estimated.…”

“…Formerly ploughed lands were indeed found to increase the carbon content in the soil profile already after 4 yr since the LUC, as a consequence of the encroachment of recovering grassland vegetation (Kurganova et al, 2008). Vuichard et al (2008), using a model prescribed with FAO data for rates of cropland abandonment, estimated a mean sink of −8 Tg C yr −1 between 1991 and 2000 (−47 g C m−2 yr −1 ). This is likely to represent an underestimate because regrowth of forest and shrubs over abandoned farmland was not modeled, and the study was restricted to southern European Russia, whereas significant abandonment took place after 2000 in Belarus, and after 1990 in Central Asia (e.g.…”

The effects of post-pasture woody plant colonization on soil and aboveground litter carbon and nitrogen along a bioclimatic transect

“…Areas subject to secondary succession are of particular interest because they might have great potential as C sinks (Alberti et al 2011). Soil C dynamics after agricultural abandonment have been quantified in many studies (Knops & Tilman 2000, Davis et al 2003, Vuichard et al 2008, Kuemmerle et al 2011, and the spread of woody plants into grasslands/pastures/croplands is generally thought to increase the C stored in these ecosystems (Pré-vosto et al 2006, La Mantia et al 2007, Montané et al 2007, Alberti et al 2011. Some authors, however, have reported that secondary succession causes a reduction in soil C (Goodale & Davidson 2002, Guo & Gifford 2002, Jackson et al 2002, Paul et al 2002, Alberti et al 2008).…”