Dados do Trabalho

Título

EFFECTS OF IMPROVED PASTURES AND INTEGRATED PRODUCTION SYSTEMS ON SOIL ORGANIC CARBON SEQUESTRATION IN BRAZIL

Resumo

Brazil offers great opportunities for contributing to climate change mitigation through carbon sequestration in pasture systems. Although several studies have been published assessing soil organic carbon (SOC), there is still a lack of information on the potential for carbon sequestration by improving pasture management, especially when integrated production systems are implemented. We aimed to derive factors for SOC stock change and potential sequestration rates for the conversion of extensive pastures into improved management or integrated production systems of crop-livestock-forest (CLFS), crop-livestock (CLS), or livestock-forest (LFS). We gathered primary studies by a systematic review process to build a database for Brazilian pasturelands, then, a mixed-effect linear regression model was fitted to estimate carbon management factors coefficients and estimate SOC stock change rates. We included 310 data pairs comparing a reference (extensive pasture) and treatment, distributed in 43 field experiments from 30 published papers. The results pointed out that for 20 years, at a 0-30 cm depth, the improvement of exclusively pasture systems has the potential to increase SOC stocks by 21% from extensive pastures, while the adoption of integrated production systems for the same reference, can enhance by 38%, for LFS, 30%, for CLFS, and 3%, for CLS. We used these management factors to analyze the C stock change rates, providing a potential to sequester over a period of 20 years, in 0-30 cm depth, 0.24 Mg C ha -¹ year-¹, for improved pastures, 0.42 Mg C ha -¹ year-¹, for LFS,  0.21 Mg C ha -¹ year-¹, for CLFS, 0.02 Mg C ha -¹ year-¹, for CLS. The LFS presented the best opportunities to store C in soil, thus, we suggest more long-term research on this system to understand how time affects the change rates. Lastly, these C factors contribute directly to national greenhouse gas emission inventories updates since they typically develop estimates based on regional studies.

Palavras-chave

pasture management, soc change, mixed-effect regression model

Instituição financiadora

Coordination for Higher Education Staff Development (CAPES)

Agradecimentos

Natural Resources and Ecology Laboratory, Colorado State University