GREENHOUSE GAS EMISSIONS IN A YELLOW LATOSOL UNDER AGRICULTURAL MANAGEMENT IN PARAGOMINAS-PA

Understanding greenhouse gas (GHG) dynamics in tropical agricultural systems is essential for improving national inventories and guiding low-emission management strategies. This study quantified soil–atmosphere nitrous oxide (N₂O) and methane (CH₄) fluxes in soybean fields managed under conventional tillage (CT) and no-tillage (NT) in very clayey Yellow Latosols of eastern Amazonia. Fluxes were measured across three phenological phases using static chambers, coupled with soil moisture and temperature monitoring. Overall, N₂O and CH₄ fluxes were low in both systems, reflecting the well-drained conditions, low water-filled pore space, and limited labile carbon characteristic of these Oxisols. N₂O emissions showed modest temporal variability but no statistical differences between CT and NT, and no rainfall-induced pulses were detected. CH₄ fluxes were negative or near zero throughout the season, indicating net atmospheric CH₄ uptake, with slightly higher consumption under NT during the late season. Soil moisture and temperature exhibited similar averages across systems, but their temporal dynamics helped explain gas-flux patterns. Collectively, the results demonstrate that microenvironmental controls exert stronger influence on GHG fluxes than tillage practices under these soil and climatic conditions. These findings provide empirical evidence to refine regional emission factors and improve the representation of tropical agricultural systems in Brazil’s GHG inventory.