祁连山自然保护区不同草地类型地上生物量和土壤微量元素特征分析

Characteristics of aboveground biomass and soil traceelements of different grassland types in Qilian Mountain reserve

摘要:

以祁连山保护区5个主要草地类型为研究对象,探讨了不同草地类型植被及土壤微量元素的分布特征,应用冗余分析(RDA)分析了微量元素对植被特征的解释关系。研究发现:1)不同类型草地植被总盖度依次为高寒草甸＞温性草原＞高寒草原＞温性荒漠＞高寒荒漠,草层高度依次为温性荒漠＞温性草原＞高寒草原＞高寒草甸＞高寒荒漠,地上生物量依次为温性草原＞高寒草原＞高寒草甸＞温性荒漠＞高寒荒漠;禾本科、豆科和杂类草生物量及比例因草地类型而异;2)随着土层深度的增加,温性荒漠和高寒荒漠土壤Mg含量降低,Mn、Zn、Fe、Cu和Mo含量升高,而高寒草甸、温性草原和高寒草原的土壤Mg、Mn和Zn含量先升高后降低,Fe、Cu和Mo含量降低;3)不同类型草地土壤微量元素含量因草地类型而异。RDA分析发现,影响草地植被特征重要性依次为Mg＞Zn＞Cu＞Mn,且Mg对植被特征的影响达显著水平。综上所述,土壤微量元素Mg、Zn、Cu和Mn与草地植被关系密切且在一定程度上影响着草地植被状况,尤其土壤Mg含量。

Abstract:

The distribution characteristics of vegetation and soil trace elements were investigated in five different types of grassland in the Qilian Mountain Reserve.The relationship between trace elements and vegetation was explained using RDA analysis.The study found that the total vegetation coverage in different types of grasslands followed the order of alpine meadow＞temperate grassland＞alpine grassland＞temperate desert＞alpine desert.The grass height was in the order of temperate desert＞temperate grassland＞alpine grassland＞alpine meadow＞ alpine desert;while the biomass followed the order of temperate grassland＞alpine grassland＞alpine meadow＞temperate desert＞alpine desert.Biomass and proportion of grasses,legumes and weeds differed among the different types of grassland.Along the increased soil depth,soil Mg content in temperate desert and alpine desert decreased,while the content of Mn,Zn,Fe,Cu,and Mo increased.Soil Mg,Mn,and Zn content in alpine meadow,temperate grassland and alpine grassland initially increased,followed by a decrease,while the soil content of Fe,Cu and Mo decreased along the soil depth.The content of soil trace elements in different types of grassland differed.The RDA analysis found that the vegetation characteristics of grassland was affected by soil trace elements following the order of Mg＞Zn＞Cu＞Mn,with Mg having significant effects.In summary,soil Mg,Zn,Cu,and Mn,particularly Mg,had close relationship with grassland vegetation and also affected grassland vegetation conditions.The characteristics of vegetation and the distribution of soil trace elements varied among different grassland types.