Interactive effects of nitrate and oxygen on methane oxidation in three different soils

Walkiewicz, A.; Brzezińska, M.

Interactive effects of nitrate and oxygen on methane oxidation in three different soils

2019

Walkiewicz, A. | Brzezińska, M.

The ability of soil to uptake methane is regulated by several factors affecting soil microbial activity. The soil oxygen concentration is usually lower than the concentration of atmospheric air, and nitrogen fertilization contributes to a significant increase in nitrate-N in soil. Therefore, we selected three agricultural soils (Eutric Cambisol, Haplic Podzol, Mollic Gleysol) to investigate interactive effects of oxygen and nitrate (KNO₃) on CH₄ oxidation including different gradients of O₂ (20%, 10%, 5%, 2%) and nitrate (0, 100, 200 mg N kg⁻¹). The soils varied in their response to O₂ and nitrate treatments. In the absence of nitrate, all soils completely oxidized added CH₄ (1%) under the oxygen concentrations used (except 2%O₂); however, low oxygen (5%; 10%O₂) was optimal. Both nitrate doses strongly stimulated methane oxidation at 2%O₂ in Podzol and Gleysol, but generally inhibited CH₄ uptake in Cambisol.

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