土壤N_2O产生的微生物过程

Microbial Processes of Nitrous Oxide Production from Soils

N2O是一种重要的温室气体,它在大气中浓度的迅速增加和其在大气化学中的重要作用,已引起科学家们的极大关注。土壤是大气N20的重要排放源,它主要通过土壤微生物的硝化和反硝化过程产生。硝化作用主要是由自养微生物和一些异养微生物在好氧条件下产生的;而反硝化作用主要由异养微生物在厌氧条件下产生的。其他过程如化学反硝化作用、异养硝化作用也会产生少量N2O,但贡献极小。

The denitrification and nitrification processes are the major sources of N_2O production in soils.Nitrous oxide is normally a minor product of these processes.Nitrification is dependent primarily on NH_4^+ supply.It is carried out mainly by autotrophic bacteria although some heterotrophic microorganisms may also be involved.Demitrification is an anaerobic process carried out by mainly facultative heterotrophic bacteria and is dependent on organic C and NO_3^- concentrations.Other processes such as chemodenitrification or hetrotrophic nitrification are generally considered to play vry minor roles in N_2O production in soils.