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土壤中氮沉降增加作为全球环境变化的重要现象之一,给人类带来了巨大挑战。笔者综述了近年来氮沉降对土壤微生物的影响研究,从土壤微生物生物量、群落结构和多样性、微生物活性、功能基因与底物利用等方面进行总结分析。综合来看,氮沉降对土壤微生物的影响主要表现为:1土壤微生物生物量、真菌生物量以及真菌与细菌生物量比值下降;2外生菌根真菌子实体生产力和外生菌根丰度下降,外生菌根真菌群落结构组成改变;3丛枝菌根真菌群落结构组成改变,但氮沉降对丛枝菌根真菌的多样性和对腐生真菌的影响结果存在较大争议;4细菌群落结构组成改变,贫营养细菌丰度下降,富营养细菌丰度上升;5土壤微生物活性下降,某些功能基因丰度下降,对复杂有机碳、氮的代谢能力下降。同时,相关研究报道表明:氮沉降可以直接或通过降低土壤p H,增加微生物的碳限制,改变底物的数量和质量等途径间接对微生物生物量和群落结构产生影响。
As an important phenomenon of global environmental change, the increase of nitrogen deposition in soil has brought great challenges to human beings. In this paper, the effects of nitrogen deposition on soil microorganisms in recent years are reviewed. The results are summarized from the aspects of soil microbial biomass, community structure and diversity, microbial activity, functional genes and substrate utilization. Taken together, the effects of nitrogen deposition on soil microorganisms are mainly as follows: 1 The ratio of soil microbial biomass, fungal biomass and fungi to bacterial biomass decreased; 2 The productivity of ectomycorrhizal fungi fruiting bodies and ectomycorrhizal abundance decreased , The structure of ectomycorrhizal fungal communities changed; 3 the structure and composition of arbuscular mycorrhizal fungi communities changed, but the effect of nitrogen deposition on the diversity of arbuscular mycorrhizal fungi and saprophytic fungi had a big controversy; 4 bacterial community structure The abundance of poorly vegetative bacteria decreased and the abundance of eutrophic bacteria increased.5 The activity of soil microorganisms decreased, the abundance of some functional genes decreased, and the metabolic capacity of complex organic carbon and nitrogen decreased. In the meantime, relevant research reports indicate that nitrogen deposition can indirectly affect microbial biomass and community structure directly or through reducing p H of soil, increasing carbon limitation of microorganisms, changing quantity and quality of substrate, and the like.