营林措施对森林土壤甲烷吸收的影响

Effect of Management Practices on Methane Uptake in Forest Soils

以期为全球气候变暖背景下的林地合理经营管理提供依据。利用Scopus,Web of Science,SDOS,CNKI等数据库,查询林地土壤CH_4的相关文献,对不同营林措施(施肥、采伐、火烧、林下植被管理)森林土壤CH_4吸收通量方面的研究进行综述。施加N肥对于富氮森林土壤CH_4吸收有抑制作用,但可以显著促进贫氮森林土壤CH_4吸收;火烧后土壤CH_4吸收通量受到多种因素的影响,因此存在一定的不确定性,多数研究表明,火烧减少土壤CH_4吸收通量;皆伐改变土壤温度、含水量、有机碳的分解和利用等,从而减弱森林土壤CH_4吸收能力;择伐对森林土壤CH_4吸收的影响表现为抑制、促进和无影响;剔除林下植被提高土壤温度,加快土壤水分蒸发散失,增强CH_4氧化菌的活性,促进土壤CH_4吸收;种植固氮植物使森林土壤转变为CH_4的排放源。目前经营措施对森林土壤CH_4吸收影响的研究结果还存在较大差异,对营林措施影响森林土壤CH_4吸收的内在机理的认识还不充分。随着研究方法和观测手段的不断发展,今后应深入研究多种因素和气候变化对林地土壤CH_4吸收影响的内在机理以及甲烷氧化菌对各种干扰因素的响应机制。

Forest soils are the main sinks of atmospheric CH4. This study is aimed to provide a basis for forest management practices under climate change. The databases of Scopus, Web of Science, SDOS and China National Knowledge Infrastructure （CNKI） were used to review current status of studies on CH4 uptake from forest soils. The review highlighted the effect of forest management practices （fertilization, cutting, burning, and understory management） on soil CH4 uptake, and explained its main mechanism. Fertilization tended to inhibit soil CH4 uptake in N-rich forest soils, but obviously promoted soil CH4 uptake in N-poor forest soils. It was generally believed that slash burning reduced soil CH4 uptake. Clear-cutting changed soil temperature, water content, decomposition of organic carbon, and thus weakened the capability of methanotrophs to oxidize methane. Selective-cutting could stimulate, suppress, or show no effect on forest soil CH4 uptake. Understory removal increased soil temperature, sped up evaporation of soil water and increased the activity of methanotrophs, which promoted soil CH4 uptake. Nitrogen fixing plants reduced soil CH4 uptake. There were significant differences of＂ management practices on forest soil CH4uptake among the previous studies. Additionally, the inherent mechanism is still not sufficient. With the development of research theory and technology, the interactive effects of various factors and climate change on forest soil CH4 uptake and its mechanism, the response model of methanotrophs to various interference factors will become the main direction in the future.