放牧改变了藏北高原高寒草甸土壤微生物群落  

Grazing alters soil microbial community in alpine grasslands of Northern Tibet

作　　者：付刚[1] 沈振西[1] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室拉萨高原生态系统研究站,北京100101

出　　处：《草业学报》2017年第10期170-178,共9页Acta Prataculturae Sinica

基　　金：国家自然基金项目(31600432;41171084);国家重点研发计划(2016YFC0502005;2016YFC0502006)资助

摘　　要：本研究基于2008年7月布设的3个围栏与自由放牧样地(一个高寒草原化草甸,冬季牧场;一个高寒草原化草甸,夏季牧场;一个典型高寒草甸,夏季牧场),开展了藏北高原高寒草甸土壤微生物群落组成对放牧的响应研究。土壤微生物群落组成采用磷脂脂肪酸方法(phospholipid fatty-acid,PLFA)测定。结果表明,冬季放牧显著降低了高寒草原化草甸的土壤真菌、革兰氏阴性细菌、放线菌和原生动物。夏季放牧显著降低了典型高寒草甸的土壤总PLFA、真菌、细菌、革兰氏阳性细菌、革兰氏阴性细菌、放线菌、丛枝菌根真菌和原生动物。基于冗余度分析,3个放牧与围栏条件下的土壤微生物群落组成都存在显著差异。土壤无机氮和水溶性有机氮显著影响着高寒草原化草甸冬季牧场的土壤微生物群落组成,而硝态氮和水溶性有机碳显著影响着高寒草原化草甸夏季牧场和典型高寒草甸夏季牧场的土壤微生物群落组成。因此,放牧对高寒草甸土壤微生物群落的影响与放牧季节和草地类型有关。A grazing experiment was conducted in two alpine steppe meadows （winter pasture and summer pasture） and one alpine meadow （summer pasture） in Northern Tibet in July 2008.The phospholipid fatty-acid （PLFA） method was used to characterise the soil microbial community.Fungi,gram-negative bacteria,actinomycetes and protozoa in ungrazed soils were significantly higher than grazed soils in winter pasture on the alpine steppe meadow.Total PLFA,fungi,bacteria,gram-positive bacteria,gram-negative bacteria,actinomycetes,arbuscular mycorrhizal fungi and protozoa in the ungrazed soils were also significantly higher than those of grazed soils in the summer alpine meadow.There were significant differences in soil microbial community structure between ungrazed and grazed soils for all three alpine grasslands based on redundancy analysis.Soil inorganic nitrogen and dissolved organic nitrogen significantly affected the variation in the soil PLFA profile in the alpine steppe meadow for the winter pasture,whereas nitrate nitrogen and dissolved organic carbon significantly affected the variation of soil PLFA profile for the summer pastures.Our findings suggested that clarifying the effect of grazing on alpine soil microbial communities needs to consider grazing season and grassland types in Northern Tibet.

关 键 词：围栏 磷脂脂肪酸 冗余度分析 放牧季节 

分 类 号：S812.2[农业科学—草业科学]