CAJ | 학술논문

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）。
위종미관시야인식“흑토탄”초지퇴화궤리급위해류형초지개량화회복제공이론의거화과기지탱，본연구이감숙성천축현고한초지위례，측정분석료초지식피、토양삼대류미생물（진균、세균화방선균）화담소생리군（안화세균、초화세균、반초화세균、호기성화혐기성고담균）재공간층차화불동계절적수량변화。결과표명：“흑토탄”초지식피이미공초화향유위우세충，기개도화식물량교저；미생물주요분포재0～20 cm，삼대류미생물수량이세균최다、진균최소，분별점총수적84．60％화0．17％；담소생리군수량이호기성고담균최다、혐기성고담균최소，분별점총수적57．51％화0．05％。미생물수량표현출명현적계절동태，8월빈체도최대치，제토양세균（10월）지외，진균、방선균화각담소생리군미생물최소치도출현재4월빈。토양담소함량、초지식물량균여초화세균、호기성고담균수량정정상관관계，이여반초화세균수량정부상관관계，병차도체도료현저수평（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.