Spatial distribution of the CO2 stream in archaeological dark earth area under cocoa and coffee cultivation in the municipality of Apuí, AM, Brazil

The Archaeological Dark Earth (ADE) are soils that can hold up to six times more organic carbon than surrounding soils without anthropic horizons, thus assuming higher CO₂ emissions from these soils. The objective of this study was to investigate the spatial distribution of CO₂ efflux, temperature and soil moisture in an Archaeological Dark Earth area under cocoa and coffee cultivation in the municipality of Apuí, AM, Brazil. Sample grids of 42 x 80 m were set up, with space between points of 8 x 6 x 10 m and 10 m, respectively, for the cocoa and coffee areas. After data of CO₂ efflux, temperature and humidity of the soil were collected, descriptive statistics and geostatistics analyses were done. The results showed that the evaluated parameters exhibited spatial dependence reaching a range of 25 to 40 m for CO₂ stream ADE area with cocoa. The CO₂ efflux in the cocoa area was higher, with an average value of 5.49 µmol m^-2 s^-1, compared to 3.99 µmol m^-2 s^-1 in the area of coffee CO₂.

Keywords:
antropic soil; CO₂ efflux; organic carbon.