土壤反硝化产物N_(2)O/N_(2)化学计量比例研究进展

Research progress on stoichiometric ratio of soil denitrification products N_(2)O/N_(2)

反硝化作用是土壤氮循环中最重要的活性氮移除途径之一。在这一过程中,硝态氮被还原为气态氮素氧化亚氮(N_(2)O)或氮气(N_(2))等离开土壤进入大气,而其气态产物N_(2)O/N_(2)化学计量比是土壤反硝化研究的热点和难点,合理调控N_(2)O/N_(2)是减少农业源温室气体排放的重要途径。在土壤环境中,反硝化产物比受多种因素的影响,硝态氮、O2含量和Cu离子有效性是介导产物比变化的关键影响因子,而电子供体量、pH、水分为一般影响因子。这些因素既可以通过影响反硝化酶活、反硝化微生物丰度和群落结构等直接作用于反硝化过程,也可以通过改变反硝化发生的土壤微环境间接影响反硝化产物比。本文综述了近年来土壤反硝化气态产物N_(2)O/N_(2)控制因素的相关进展,并讨论了其对不同影响因素变化的响应机理,以期为后续相关研究提供思路和背景。

Denitrification is one of the most important reactive nitrogen removal pathways in the soil nitrogen cycle.In this process,nitrate is reduced to gaseous nitrogen nitrous oxide(N_(2)O)or nitrogen(N_(2)),which leaves the soil and enters the atmosphere.The stoichiometric ratio of its gaseous products N_(2)O/N_(2)is a hot topic in soil denitrification research.Reasonable regulation of this ratio is an important way to reduce greenhouse gas emissions from agricultural sources.In the soil environment,the ratio of denitrification products is affected by many factors.In our view,nitrate content,oxygen,and copper availability are the key factors mediating the change of the product ratio,while electron donors,pH,and moisture are general factors.These factors can directly affect the denitrification process by affecting denitrifying enzyme activity,denitrifying microorganism abundance,and community structure.They can also indirectly affect the ratio by changing the soil microenvironment of denitrification.This paper reviews the progress made toward controlling the factors affecting the soil denitrification gaseous product ratio N_(2)O/N_(2)in recent years and discusses the response mechanism of the denitrification product ratio to different influencing factors to provide some inspiration for future related research.