Carbon dioxide (CO2) is produced only in biological activities. Understanding how soil tillage practices affect the dynamics of CO2 production is important, as these processes are influenced by the temperature and humidity conditions of the place. This paper aimed at quantifying CO2 flux in hydromorphic floodplain soils under different açai palm tree grove management strategies, correlating it with litter deposition, soil environment, and season of the year. Conducted in the city of Mazagão-AP, four areas of açai palm tree groves were selected with different types of management. During the evaluation period (October, November, and December 2012, and February, March, and April 2013), CO2 flux, soil moisture, and temperature were measured, and litter samples were collected. In addition, rainfall data for the region were also obtained. The CO2 fluxes obtained ranged from 0.37 to 28.55 μmol CO2 m-2 s-1, with a total average of 6.20 μmol CO2 m-2 s-1. In broad analysis, soil variables did not show significant correlations with CO2 emissions. A positive relationship between flux and litter and soil temperature, as well as a negative relationship with its moisture, were observed only in a few months and specific systems.