FLUXO DE GASES DO EFEITO ESTUFA DO SOLO SOB DIFERENTESCOBERTURAS NAS ESTAÇÕES DO ANO

Abstract

The increase in greenhouse gas (GHG) emissions from agricultural activities has intensified concerns regarding the environmental impacts associated with climate change, highlighting the need for studies aimed at understanding the dynamics of these gases within the soil–atmosphere system. In this context, the present study aimed to evaluate the fluxes of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) in different agricultural production systems in the municipality of Rio Verde, Goiás, Brazil, analyzing the influence of management systems and seasonality on emissions. The study was conducted on five rural properties representing different land-use systems, including forest, pasture, agroforestry, sugarcane, corn, soybean, sorghum, and fallow areas. Sampling was carried out throughout the four seasons of the year using a soil gas flux chamber (Smart Chamber) coupled with LI COR 7810 and 7820 gas analyzers. Simultaneously, environmental variables such as soil temperature and soil moisture were measured. The results showed that seasonality strongly influenced GHG fluxes, particularly CO₂, which presented the highest emissions during summer (4.51 µmol m⁻² s⁻¹) due to higher temperatures and increased microbial activity. CH₄ showed a predominance of negative values in most evaluations, indicating that soils acted as sinks for this gas, especially in forest and agroforestry areas. N₂O showed greater variation among land-use systems, with the highest emissions observed in corn-cultivated areas (0.822 nmol m⁻² s⁻¹), possibly due to the greater availability of nitrogen resulting from nitrogen fertilization. In general, systems with lower management intensity and greater vegetation cover showed greater potential for mitigating greenhouse gas emissions, whereas more intensive agricultural systems showed higher emission trends. Thus, it can be concluded that climatic factors and soil management directly influence greenhouse gas dynamics, highlighting the importance of sustainable agricultural practices, such as agroforestry systems, crop-livestock-forest integration (CLFI), and no-tillage systems, for mitigating emissions in the agricultural sector.