Effects of Nitrogen Addition on Gas Fluxes and Nitrification in Cerrado Soil under a Controlled Incubation Essay by Land Use

This study evaluated the effects of ammonium sulfate [(NH₄)₂SO₄] addition and land use history on greenhouse gas emissions (CH₄, CO₂, N₂O) and inorganic nitro-gen dynamics (NH₄⁺ and NO₃⁻) in Brazilian Cerrado soils. Soil samples from native and agricultural areas (0–20 cm) were collected in four representative regions (Araras, Sorocaba, Itirapina, and Brasília) and incubated under controlled conditions, analyzed by gas chromatography and colorimetric methods. Nitrogen fertilization inhibited CH₄ consumption in both native and agricultural soils from Araras, Brasília, and Itirapina, and in Itirapina reversed the flux to emissions, likely due to microbial competition and soil texture, with CH₄ consumption positively correlated with sand content (r = 0.55). CO₂ emissions increased in native soils from Araras and Brasília but decreased in ag-ricultural Araras, suggesting that fertile, moist soils favor respiration, while higher carbon stocks stabilize emissions (r = –0.47). N₂O emissions increased in native soils, especially in Araras, Itirapina, and Sorocaba, reflecting intensified nitrification and denitrification, whereas agricultural soils responded heterogeneously. Nitrogen addi-tion reduced NO₃⁻ consumption and increased NH₄⁺ consumption, indicating enhanced oxidation and microbial assimilation. These results show that land-use history modulates soil biogeochemical responses to nitrogen, emphasizing the need for site-specific fertilization to mitigate emissions and promote agricultural sustainability in the Cerrado.