Monitoring of Carbon Stocks in Pastures in the Savannas of Brazil through Ecosystem Modeling on a Regional Scale

In 2020, Brazil was the seventh largest emitter of GHG (greenhouse gases), releasing similar to 2.16 GtCO2e (gigatons of carbon dioxide equivalent) into the atmosphere. Activities related to land use contributed approximately 73% of national emissions in that year. Considering that pastures represent the primary land use in the country, occupying approximately 20% of the territory, the mapping and monitoring of C stocks in these areas is essential to determine their contribution to national emissions. In this study, based on the integrated use of the CENTURY model, georeferenced databases, and the R environment, we mapped and analyzed, for the first time, the C stocks dynamics associated with the pasture areas 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 similar to 31 MgC center dot ha(-1) and similar to 4 MgC center dot 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 (similar to 34 MgC center dot ha(-1)) and the lowest in Neosols (similar to 29 MgC center dot ha(-1)). The temporal dynamics of soil C stocks in these areas are directly related to the age of the pastures. In fact, stocks tend to be reduced in recently converted areas and stabilized in areas that have been under this land use for a longer time (>= 30 years). As a result, a loss of similar to 103 MtC (millions of tons of carbon) was estimated in the Cerrado pasture soils in twenty years. The mapping and monitoring of 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.

Automated summary

Brazil, the seventh largest emitter of greenhouse gases in 2020, showed that 73% of its emissions were related to land use. This study utilized the CENTURY model, georeferenced databases, and the R environment to map and analyze the dynamics of carbon stocks in the pasture areas of the Cerrado biome from 2000 to 2019. The results revealed a loss of approximately 103 MtC in Cerrado pasture soils over the past twenty years. Mapping and monitoring carbon stocks in this land use type are crucial in supporting Brazil's efforts to mitigate carbon emissions.