Abstract:

Temperature affects methane oxidation in soils. We studied CH₄ consumption in agricultural soils including dark brown earth (Jilin)，fluvoaquic soil (Hebei)，and paddy soils (Anhui and Jiangxi) that were incubated at 5， 15， 25 and 35 ℃ for up to 44 days. All of the soils except paddy soils (Jiangxi) showed that the suitable temperature for CH₄ consumption was 2535 ℃，but no activity at 5 ℃ and 15 ℃. Both dark brown soil (Jilin) and paddy soil (Anhui) had similar ability at 25 ℃ and 35 ℃，the maximum average rates of CH₄ oxidation were 4.42 μg·g-1·d-1and 5.60 μg·g-1·d-1. The average rate of CH₄ oxidation of fluvoaquic soil (Hebei) at 25 ℃ was twice as big as the rate at 35 ℃. Paddy soil (Jiangxi) could consume CH₄ at any temperature. The average rates of CH₄ oxidation increase with rising temperature and the rate at 35 ℃ was 3 times as the rate at 5 ℃. The maximum rate of CH₄ oxidation at 2535 ℃ follows this sequence：paddy soil (Jiangxi)>fluvoaquic soil (Hebei)>paddy soil (Anhui)>dark brown earth (Jilin). We concluded that temperature can be an important factor affecting the CH₄ consumption in agricultural soils and the temperature 2535 ℃ would be suitable for CH4 oxidation than 515 ℃. Both dry farm and rice field had significant ability of CH₄ consumption. This study will provide an important evidence for agricultural soil carbon pool research.

Key words: methane, methane oxidation, temperature