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模拟大气氮沉降对温带森林土壤微生物群落结构的影响

许可,王春梅*,张艺,杨欣桐,刘卫敏   

  1. (北京林业大学环境科学与工程学院, 北京 100083)
  • 出版日期:2016-10-10 发布日期:2016-10-10

Effect of simulated atmospheric nitrogen deposition on soil microbial community structure in a temperate forest.

XU Ke, WANG Chun-mei*, ZHANG Yi, YANG Xin-tong, LIU Wei-min   

  1. (College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China).
  • Online:2016-10-10 Published:2016-10-10

摘要:

本研究以温带森林土壤为研究对象,设置野外模拟氮沉降实验,分析不同施氮形态和施氮水平对微生物群落结构的影响。试验设置对照(Control,0 kg N·hm-2·a-1)、混合态低氮(NH4NO3,50 kg N·hm-2·a-1)、混合态高氮(NH4NO3,150 kg N·hm-2·a-1)、铵态氮低氮((NH4)2SO4,50 kg N·hm-2·a-1)、铵态氮高氮((NH4)2SO4,150 kg N·hm-2·a-1)、硝态氮低氮(NaNO3,50 kg N·hm-2·a-1)、硝态氮高氮(NaNO3,150 kg N·hm-2·a-1)7种氮处理,持续施氮3年后,运用磷脂脂肪酸(PLFA)法对土壤微生物群落结构进行测定。结果表明:在不同水平的氮添加下,土壤微生物总量、细菌、土壤革兰阳性细菌(G+细菌)、土壤革兰阴性细菌(G-细菌)和真菌的PLFA含量均随施氮水平的增加而升高;在不同形态的氮添加下,混合态氮添加提高了微生物总量、细菌、真菌和放线菌的PLFA含量。主成分分析(PCA)表明,除铵态氮低氮添加样地外,其他氮添加处理样地中的土壤微生物结构都发生了改变。这些结果表明,模拟大气氮沉降初期,氮添加会增加温带森林土壤微生物生物量,达到一定水平后会改变土壤微生物群落结构。

关键词: 土地覆盖, 地理加权回归, 空间非平稳性, 地表温度, 京津唐城市群

Abstract: Atmospheric nitrogen (N) deposition is a serious threat to global ecosystems. Soil microbes are sensitive to environmental changes. Investigating the effects of N deposition on soil microbial community structure may provide theoretical basis for scientific management of forest ecosystems. A manipulative field experiment was conducted to investigate the effects of different forms (NH4NO3, (NH4)2SO4, NaNO3) and different levels (0, 50, 150 kg N·hm-2·a-1) of N addition on the microbial community structure in a temperate forest soil. Soil microbial community structure was measured using the method of phospholipid fatty acid analysis (PLFA) after three consecutive years of N addition treatments. Our results showed that the amounts of total PLFA, bacterial PLFA, G+ bacterial PLFA, G- bacterial PLFA and fungal PLFA in N addition plots were significantly higher than that in control plots, and N addition increased the amount of microbial PLFA significantly in the order of high N addition > low N addition > control. The amounts of total PLFA, bacterial PLFA, fungal PLFA and actinomyces PLFA in NH4NO3N addition plots were generally higher than that in NaNO3N addition and (NH4)2SO4N addition plots at the same N addition level. Principal component analysis (PCA) showed that microbial community structures were changed in all Nadded plots except the low (NH4)2SO4N addition plots. Overall, these results suggested that N addition would increase soil microbial biomass and change soil microbial community structure in forest soils when N addition level reaches a threshold, at least over the short term.

Key words: geographically weighted regression (GWR), Beijing-Tianjin-Tangshan urban agglomeration, land cover, land surface temperature (LST), spatial non-stationarity.