厦门大学学报（自然科学版）2025，Vol.64Issue(3)：511-517,7.DOI:10.6043/j.issn.0438-0479.202401022
西藏米拉山不同海拔高山草地土壤有机碳分布特征
Distribution characteristics of soil organic carbon in alpine grassland at different elevations in Mila Mountain,Xizang
摘要
Abstract
[Objective]To explore the characteristics of change in soil organic carbon(SOC)content along an elevation gradient in the alpine grassland of Xizang,the scientific question to be answered is"What are the distribution characteristics of SOC at different elevations in a mountain ecosystem?"The results are of great significance for predicting the impact of global climate change on the alpine grassland ecosystem in permafrost region and for providing a reference for the systematic understanding of soil carbon and nitrogen cycling in this region.[Methods]The changes in SOC,soil organic nitrogen(SON),soil microbial biomass carbon(SMBC),soil microbial biomass nitrogen(SMBN),particulate organic carbon(POC)and readily oxidizable organic carbon(ROC)contents,as well as their components along the elevation gradient and influencing factors,were studied by randomly setting samples at different depths in the alpine grassland on the eastern slope of Mila Mountain in Xizang,located at 4 409-5 108 m above sea level.Soil samples were collected by digging soil profiles.Soil sample pits of 120 cm deep were dug in each sample plot,and 100 cm3ring knives were used to separate bulk heavy soil and soil samples in layers of 0-20 cm,＞20-60 cm,and＞60-120 cm.A total of 54 bulk heavy soil and soil samples were collected.The plant roots and gravel were then removed,and the soil samples from the same pit were mixed the same layer.One sample was refrigerated in an incubator and the other was brought back to the lab for air drying to determine the SOC content.[Results]1)With increasing elevation,soil pH of the alpine grassland gradually increased from 4.63 to 6.35,bulk density gradually decreased.With the increase of soil depth,soil pH and bulk density increased.2)SOC,SON,SMBC,SMBN,POC and ROC contents were negatively correlated with elevation and soil depth.Their contents were highest in the 0-20 cm soil layer at 4 409 m:54.13 g/kg,1.27 g/kg,186.23 mg/kg,3.89 mg/kg,43.15 g/kg and 17.82 g/kg,respectively.3)The changes in SOC,SON,SMBC,SMBN,POC and ROC contents were caused by changes in elevation,such as variations in hydrothermal conditions,soil physicochemical properties,vegetation composition,and so on.The results indicated that the changes in SOC and its component contents caused by elevation changes were important factors affecting the stability of SOC in the alpine grassland of Mila Mountain.[Conclusion]Soil depth has a significant influence on the contents of SOC,SON,SMBC,SMBN,POC and ROC.The possible reason is that the increase in soil compactness and the decrease in soil porosity hinder the infiltration of water.In low elevation areas,higher plant species richness and biomass lead to greater accumulation of soil organic matter and more carbon into the soil,resulting in the highest SOC and its components contents.Overall,changes in elevation lead to changes in hydrothermic factors,soil physical and chemical properties,and vegetation composition in Mila Mountain,which in turn affect the input and output patterns of organic carbon by vegetation.Vegetation productivity influences SOC input by altering the amount of litter returned.关键词
土壤有机碳/土壤微生物量碳/土壤微生物量氮/高山草地/米拉山Key words
soil organic carbon/soil microbial biomass carbon/soil microbial biomass nitrogen/alpine grassland/Mila Mountain分类
农业科技引用本文复制引用
马和平,吴亚轩,司孟鑫,王彪,陈利..西藏米拉山不同海拔高山草地土壤有机碳分布特征[J].厦门大学学报（自然科学版）,2025,64(3):511-517,7.基金项目
西藏自治区2023年科技计划项目(XZ202301ZY0041G) （XZ202301ZY0041G）
西藏农牧学院农业资源与环境学科建设项目(2024) （2024）
西藏农牧学院林学博士点(一期)(533325001) （一期）
