高寒生态脆弱区“黑土滩”草地植被与土壤微生物数量特征研究  

Characteristics of vegetation and soil microorganisms of molehill grassland in an ecologically vulnerable alpine region

作　　者：卢虎[1] 李显刚 姚拓[1] 蒲小鹏[1] 

机构地区：[1]甘肃农业大学草业学院中-美草地畜牧业可持续发展研究中心,甘肃兰州730070 [2]贵州省黔南州饲草饲料工作站,贵州黔南558000

出　　处：《草业学报》2014年第5期214-222,共9页Acta Prataculturae Sinica

基　　金：国家自然基金(31360584);国家科技支撑计划(2012BAC01B02-4);甘肃省农业科技创新项目(GNCX-2012-45)资助

摘　　要：为从微观视野认识“黑土滩”草地退化机理及为该类型草地改良和恢复提供理论依据和科技支撑，本研究以甘肃省天祝县高寒草地为例，测定分析了草地植被、土壤三大类微生物（真菌、细菌和放线菌）和氮素生理群（氨化细菌、硝化细菌、反硝化细菌、好气性和嫌气性固氮菌）在空间层次和不同季节的数量变化。结果表明：“黑土滩”草地植被以微孔草和香薷为优势种，其盖度和植物量较低；微生物主要分布在0～20 cm，三大类微生物数量以细菌最多、真菌最少，分别占总数的84．60％和0．17％；氮素生理群数量以好气性固氮菌最多、嫌气性固氮菌最少，分别占总数的57．51％和0．05％。微生物数量表现出明显的季节动态，8月份达到最大值，除土壤细菌（10月）之外，真菌、放线菌和各氮素生理群微生物最小值都出现在4月份。土壤氮素含量、草地植物量均与硝化细菌、好气性固氮菌数量呈正相关关系，而与反硝化细菌数量呈负相关关系，并且都达到了显著水平（P＜0．05）。In order to better define the soil dynamics of the black beach soil,in grassland dynamics and provide theory and techniques for grassland restoration informed by microbiology,we researched the soil of molehills in an ecologically vulnerable alpine region of Tianzhu County,Gansu Province.We detected and analyzed the mi-crobial population of 3 main categories of soil microorganisms （fungi,bacteria and actinomycetes）and the bac-teria groups involved in nitrogen transformation （ammonifiers,nitrifiers,denitrifying bacteria,aerobic and an-aerobic nitrogen fixing bacteria）.Taxa were cataloged by soil depth and season of sample collection using plate colony count and MPN methods.In addition,the above-ground plant biomass and total Soil N content were in-vestigated by regular methods.Key results are：the dominant species in molehill grassland was Microula sikki-mensis,the vegetation coverage and above-ground plant biomass was low.The seasonal dynamic of microbial population was well defined.The maximum number of taxa of fungi,bacteria,actinomycetes and N-transfor-ming bacteria was observed in the 0-20 cm soil layer in August,and the minimum in the 20-40 cm layer in April ,except for the ammonifier and aerobic N-fixing soil bacteria for which the number was observed in Octo-ber.There was a positive correlation between both soil N and plant biomass and the microbial population of ni-trifiers and aerobic N-fixing bacteria.By contrast,there was a negative correlation between soil N and denitrif-ying bacteria.

关 键 词：“黑土滩”草地 土壤微生物 氮素生理群 高寒生态脆弱区 土壤氮素 

分 类 号：S812.2[农业科学—草业科学]