祁连山国家公园不同类型草地植被及土壤特征研究

Study on Vegetation and Soil Characteristics of Different Types of Grassland in Qilian Mountain National Park

为掌握祁连山国家公园内不同草地类型植被及土壤特性的差异,对祁连山国家公园青海片区门源县的高寒荒漠、高寒草甸、高寒湿地和温性草原的植被特性、土壤理化性质和土壤微生物进行研究。结果表明:高寒草甸、高寒湿地以莎草科和禾本科植物为主,高寒荒漠以景天科植物为主;高寒草甸的植被盖度和地上生物量最高,分别为98.83%和348.67 g/m^(2);高寒湿地和高寒草甸的土壤含水量分别为92.05%和57.99%,显著高于温性草原与高寒荒漠(P<0.05);而高寒湿地和高寒草甸的土壤孔隙度分别为74.35%和70.01%,显著高于温性草原和高寒荒漠(P<0.05);不同草地类型土壤的速效氮、全氮和有机质含量均呈现高寒草甸>高寒湿地>温性草原>高寒荒漠的趋势。相关性分析表明,植被盖度与土壤容重极显著负相关(P<0.01),与土壤全氮、速效氮显著正相关(P<0.01)。在土壤含水量更高的高寒湿地中放线菌门(Actinobacteria)相对丰度较低,且由于透气性差、土壤含氧量低,导致高寒湿地中好氧微生物丰度少,群落结构脆弱。在土壤含水量较低、土壤透气性好的高寒荒漠中酸杆菌门(Acidobacteria)、被孢霉门(Mortierellomycota)等好氧微生物相对丰度较高。在植被丰富、地上生物量高的温性草原、高寒草甸中担子菌门(Basidiomycota)丰度较高。该研究结果揭示了不同草地类型的植被、土壤和微生物间的相互关系,为祁连山国家公园草地生态系统的可持续利用及科学管理提供了基础数据。

In this research,vegetation characteristics,soil physicochemical properties,and soil micro-organisms of the alpine desert,alpine meadows,alpine wetlands,and temperate grasslands of the Qilian Mountain National Park in Qinghai part in Menyuan County were investigated to understand the differences of various grassland types.The results showed that the alpine meadows and alpine wetlands were mainly composed of Cyperaceae and Gramineae plants,while Crassulaceae plants dominated the alpine deserts.The vegetation coverage and above-ground biomass of the alpine meadows were the highest at 98.83%and 348.67 g/m^(2),respectively.The soil water content of the alpine wetland and alpine meadows was signifi-cantly higher(P<0.05)than that of the temperate grassland and alpine deserts.The soil porosity of the alpine wetlands and alpine meadows was significantly higher(P<0.05)compared to the temperate grass-lands and alpine deserts.The content of the available nitrogen,total nitrogen,and organic matter in the soils of the different grassland types showed a trend of alpine meadows>alpine wetlands>temperate grass-lands>alpine deserts.The correlation analysis showed that the vegetation coverage had a significantly negative correlation with the soil bulk density(P<0.01),and positively correlated with the soil available nitrogen and total nitrogen significantly(P<0.01).The relative abundance of Actinobacteria was a little lower in alpine wetlands with high soil water content.Meanwhile,due to the poor permeability and low soil oxygen content,the abundance of the aerobic microorganisms was lower and the community structure was more fragile.However,the aerobic microorganisms such as Acidobacteria and Mortierellomycota were relatively more abundant in the alpine deserts with the lower soil moisture and better soil permeability.The abundance of Basidiomycota was higher in the temperate grasslands and alpine meadows with the abundant vegetation and great above-ground biomass.This result reveals the relationships of the vegetation,soil,and microorganisms among the different grassland types,and provides the basic data for the sustainable use and scientific management of the grasslands in the Qilian Mountain National Park.