摘要
[目的]探究氮沉降下滇中高原云南松土壤化学性质及土壤微生物群落多样性和结构组成的变化特征,并分析土壤微生物与土壤化学性质的相关关系,为了解氮沉降下森林土壤生态系统养分循环变化趋势及观测土壤微生态变化提供科学依据.[方法]选取滇中高原云南松林土壤为研究对象,以CO(NH2)2为N源,设置对照 CK[N 0 g/(m2·a)]、低氮 LN[N 10 g/(m2·a)]、中氮 MN[N 20 g/(m2·a)]和高氮 HN[N 25 g/(m2·a)]4个不同梯度进行模拟N沉降试验,测定分析土壤细菌、真菌群落结构及多样性和土壤pH、有机碳(TOC)、全氮(TN)、全磷(TP)、铵态氮(NH4+-N)和硝态氮(NO3--N)的变化特征.[结果](1)在不同季节下,与CK相比各氮处理下土壤pH、TOC含量均降低,TN均升高,NH4+-N和NO3--N均在MN、HN处升高;(2)细菌和真菌α多样性雨季均高于旱季;与CK相较细菌α多样性在2个季节下LN处上升,而真菌a多样性则在旱季LN处上升;(3)在旱季和雨季细菌优势菌门均为变形菌门、酸杆菌门和放线菌门,真菌优势菌门为担子菌门、子囊菌门和被孢菌门;(4)在旱季和雨季,细菌和真菌优势菌属与pH、TOC、TN、NO3--N呈显著相关关系.[结论]氮沉降可以为土壤微生物提供NH4+-N和NO3--N等有效养分,但由于氮沉降导致土壤酸化使土壤TOC含量降低,影响土壤微生物群落结构.
Abstract
[Objective]To study the characteristics of changes in chemical properties and diversity and structural composition of soil microbial communities in Pinus yun-nanensis soils on the Central Yunnan Plateau under nitrogen deposition,and to analyze the correlation between soil microorganisms and soil chemical properties,in order to provide a scientific basis for understanding the trend of changes in nutrient cycling in forest soil ecosystems under nitrogen deposition and observing soil microbiological changes.[Method]The soil of P.yunnanensis forests on the Central Yunnan Plateau was selected as the research object,CO(NH2)2 was used as the N source,and four different gradients were set up for simulated N deposition experiments,including control CK[N 0 g/(m2·a)],low nitrogen LN[N 10 g/(m2·a)],medium nitrogen MN[N 20 g/(m2·a)],and high nitrogen HN[N 25 g/(m2·a)],the structure and diversity of soil bacterial and fungal community were analyzed,and the characteristics of the changes of soil pH,TOC,TN,TP,NH4+-N and NO3--N were determined.[Results](1)In both the dry and rainy seasons,soil pH and TOC content were reduced,and TN was increased under each N treatment when compared with CK,and both NH4+-N and NO3--N were increased at MN and HN compared to CK;(2)Both bacterial and fungal α-diversity were higher in the rainy season than in the dry season;bacterialα-diversity increased at LN under both seasons compared to CK,whereas fungi α-diversity increased at LN in the dry season;(3)In both the dry and rainy seasons,the dominant bacterial phyla were Proteobacteria,Acidobacteria and Actinobacteria,and the dominant fungal phyla were Basidiomycota,Ascomycota and Mortierellomycota;(4)The dominant bacterial and fungal genera were significantly correlated with pH,TOC,TN and NO3--N during the dry and wet seasons.[Conclusion]Nitrogen deposition can provide soil microorganisms with effective nutrients such as NH4+-N and NO3--N,but soil acidification due to nitrogen deposition can reduce soil TOC content and affect the structure of soil microbial communities.
维普
万方数据