摘要:氨氧化由氨氧化细菌（AOB）和氨氧化古菌（AOA）共同执行，是土壤硝化过程的第一步和限速步骤。放牧过程中，动物啃食、排泄和践踏等行为将影响土壤氨氧化微生物群落，但目前关于不同类型放牧对湿地氨氧化微生物群落结构及其多样性的影响尚不清楚。利用Illumina Mise高通量测序技术，对比研究牦牛放牧和藏香猪放养两种放牧类型对泥炭沼泽土壤氨氧化微生物群落结构及其多样性的影响。结果表明，牦牛放牧显著增加土壤容重，显著降低土壤pH、TN、TOC、NH₄⁺-N和NO₃^--N含量；藏香猪放养显著增加土壤NO₃^--N含量和硝化潜势（PNR）。牦牛放牧显著降低土壤AOA的丰富度和AOB的α多样性，藏香猪放养降低土壤AOA的α多样性和AOB的丰富度。放牧显著降低泉古菌门（Crenarchaeota）的相对丰度。AOA的α多样性与土壤NO₃^--N含量和PNR呈显著负相关。AOB的α多样性与pH、TOC、TN和NH₄⁺-N含量呈显著正相关。放牧影响下土壤pH、TN和NO₃^--N含量的变化是影响AOA群落结构的主要因素。藏香猪放养对AOA和AOB群落的影响更显著，由放牧引起的土壤环境条件的变化是导致氨氧化微生物群落发生改变的重要因素。



Abstract:Ammonia-oxidation, performed by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is the first and rate-limiting step for soil nitrification process. In the process of grazing, the animal feeding, excretion and trampling will affect the ammonia-oxidizing microorganism communities, while it is unclear whether the different grazing forms will affect the community structure and diversity of ammonia-oxidizingmicroorganism in wetlands. We investigated the diversity and community structure of the AOA and AOB with different grazing forms in peat swamp soils by Illumina Miseq high-throughput sequencing technology. The results showed that yak grazing significantly increased the bulk density, reduced soil pH, NH₄⁺-N, TN, TOC and NO₃^--N content. The stocking of Tibetan spiced pig significantly increased soil NO₃^--N content and potential nitrification rate (PNR).Yak grazing significantly reduced the richness of AOA and the α diversity of AOB. The stocking of Tibetan pigs reduced the α diversity of AOA and the richness of AOB. The grazing significantly reduced the relative abundance of Crenarchaeota. The α diversity of AOA was significantly negative correlated with soil NO₃^--N content and PNR. The α diversity of AOB was significantly positive correlated with pH, TOC, TN and NH₄⁺-N content. The change of the pH, TN and NO₃^--N content in soil was the main factor affecting the community structure of AOA with the different grazing forms. The stocking of Tibetan spiced pig had more significant effect on the AOA and AOB community. The change of soil environmental conditions caused by grazing was an important factor leading to the change ofammonia-oxidizing microorganism communities.





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