A comprehensive assessment of greenhouse gas emissions research in the Cerrado region, Brazil

The increasing demand for food, fiber, and (bio)energy boosted by population growth has accentuated agricultural expansion, increasing global greenhouse gas (GHG) emissions. This scenario is valid in Brazil, where agriculture accounts for the largest part of the nation's GHG emissions, primarily associated with the expansion of agriculture over areas of native vegetation, especially in the Cerrado region. However, despite the contribution of this sector to GHG emissions, there is a limited understanding of how different systems affect these emissions, as well as the current state of the art on this topic. Therefore, we performed a comprehensive literature review to synthesize the information about GHG emissions in the region, including cropping systems where GHG was measured, methodological procedures, and the main results achieved. Our review shows that the subject of "GHG" has been poorly investigated, with a huge discrepancy compared to other related topics such as soil organic matter. Most studies (31 % of 236) only mentioned GHG-related terms but did not measure them. The studies that measured GHG (n = 39) were conducted mainly in the south-central part of the region and were mostly limited to short-term experiments (< 5 years) or monitoring periods (< 1 year), using manual static chambers. The analysis of the available GHG data indicated that converting Cerrado into agriculture increases N2O emissions by 0.45 kg ha(-1) year(-1) while decreasing CH4 influx by 3 kg ha(-1) year(-1). Despite that, notillage combined with cover crops effectively reduces N2O emissions ( -0.3 kg ha(-1) year(-1)). Our findings reveal a significant gap in monitoring GHG fluxes in the Cerrado region, particularly in the northern part where Brazil's new agricultural frontier, the Matopiba region, is located. Efforts should prioritize generating comprehensive GHG data for Cerrado agriculture by employing more robust monitoring protocols. This would help guide producers, researchers, and policymakers to enhance agricultural management practices toward greater sustainability. (AU)