若尔盖湿地土壤有机碳含量和密度的分布特征

Distribution characteristics of soil organic carbon content and density in Zoige wetland

湿地是重要的土壤有机碳库,为维持全球二氧化碳平衡提供重要保障。为了解高寒湿地土壤有机碳水平和垂直变化特征,本研究以若尔盖高寒湿地为对象,采集不同植被类型(湿地植被和草地)不同深度的土壤样本,分析土壤有机碳分布特征。结果表明,土壤有机碳的垂直分布呈现出两种不同的特征:一是随土壤深度增加土壤有机碳含量和密度显著下降,最高值和最低值倍数达到20.03倍和7.47倍;二是随土壤深度增加土壤有机碳含量和密度波动变化,且在深层土壤中仍保持较高水平,最高值和最低值相差只有2.90倍和1.48倍;若尔盖高寒湿地土壤有机碳含量和密度的水平分布具有明显的空间异质性,湿地土壤有机碳含量和密度显著高于草地并且土壤含水率高的样点的土壤有机碳含量和密度显著高于土壤含水率低的样点。本研究表明,若尔盖高寒湿地土壤有着很强的固碳能力,并且较高的土壤含水量是维持若尔盖高寒湿地土壤碳汇功能的重要前提。研究结果对高寒湿地生态环境管理及可持续发展具有重要意义。

Wetlands are an important reservoir of soil organic carbon and provide an important guarantee for maintaining global carbon dioxide balance.In this study,we collected soil samples at different depths of different vegetation types(wetland vegetation and grassland)from alpine wetland in Zoige,to analyze the horizontal and vertical variation characteristics of soil organic carbon.We found two different characteristics of the vertical distribution of soil organic carbon.First,the content and density of soil organic carbon decreased significantly with increasing soil depth,with the difference between maximum and minimum values being 20.03 times and 7.47 times,respectively.Second,the content and density of soil organic carbon fluctuated with increasing soil depth,and maintained a high level in deep layer,with the difference between the highest and lowest values being only 2.90 times and 1.48 times.The horizontal distribution of soil organic carbon content and density in Zoige alpine wetland showed obvious spatial heterogeneity.The content and density of soil organic carbon in wetland soil were significantly higher than that in grassland,and both characteristics of the samples with high soil moisture content were significantly higher than those with low soil moisture content.In conclusion,the Zoige alpine wetland soil has a strong carbon sequestration capacity,with high soil water content being an important prerequisite for maintaining soil carbon sequestration function of Zoige alpine wetland.Our results are of great significance to the ecological environment management and sustainable development of alpine wetland.