Monitoring of carbon stocks in pastures in the savannas of Brazil through ecosystem modeling on a regional scale

Abstract In 2020, Brazil was the seventh largest emitter of GHG (Greenhouse Gases), releasing ~ 2.16 GtCO2e (gigatons of carbon dioxide equivalent) into the atmosphere. Activities related to land use contributed to approximately 73% of national emissions in that year. Considering that pastures represent the primary land use in the country, the mapping and monitoring of C stocks in these areas are essential to determine their participation in national emissions. In this study, based on the integrated use of the Century model, georeferenced databases, and the R environment, we mapped and analyzed the C stocks dynamics in the pastures of the Cerrado biome between 2000 and 2019. The average C stocks in the soil (0–20 cm) and in the aboveground biomass estimated by modeling were ~ 31 MgC.ha− 1 and ~ 4 MgC.ha− 1, respectively, values close to those observed in the literature for the region. Furthermore, the model results corresponded to the edaphic patterns of the region, with the highest average estimated C stocks in Cambisols (~ 34 MgC.ha-1) and the lowest in Neosols (~ 29 MgC.ha-1). The temporal dynamics of soil C stocks in these areas are directly related to the age of the pastures, with a reduction in stocks from recently converted areas and stabilization in areas that have been under this land use for a longer time (≥ 30 years). As a result, a loss of ~ 103 MtC (Millions of tons of Carbon) was estimated in the Cerrado pasture soils in twenty years.The mapping and monitoring C stocks in this land use type through approaches such as the one presented in this study is essential to support the Brazilian Government's efforts to mitigate C emissions.