藏东南林线过渡带土壤有机碳载体特征  

Characteristics of Soil Organic Carbon Carriers in the Timberline Transition Zone in Southeast Tibet

作　　者：骆永春 王君惠 乔锋 李晶 LUO Yongchun;WANG Junhui;QIAO Feng;LI Jing(Sichuan-Tibet Railway Co.,Ltd.;College of Resource and Environment,Tibet Agricultural and Animal Husbandry University,Nyingchi Tibet,860000,China;Seabuckthorn Development and Management Center of Development and Management Center for Soil and Water Conservation Plants,Ministry of Water Resources,Beijing,100017,China)

机构地区：[1]川藏铁路有限公司 [2]西藏农牧学院资源与环境学院,西藏林芝860000 [3]水利部沙棘开发管理中心水利部水土保持植物开发管理中心,北京100017

出　　处：《高原农业》2022年第3期243-252,共10页Journal of Plateau Agriculture

基　　金：水利部沙棘开发管理中心项目(2017-zg-zx-57)。

摘　　要：为探明藏东南林线过渡带土壤团聚体的粒径分布、结构稳定性、有机碳载体分布特征。本研究以色季拉山林线过渡带为研究区域,采用重铬酸钾外加热法测定有机碳含量,采用干筛法和湿筛法测定土壤团聚体含量。结果如下:林线样地中3种典型植被土壤非水稳定性团聚体含量有较大差异,大部分为≥0.25 mm的土壤粒径团聚体;与非水稳定性团聚体相比,﹤0.25 mm粒径的水稳性团聚体含量较高,≥0.25 mm粒径团聚体含量较低;干筛法试验测得的MWD和GMD值均远大于湿筛法,这说明该土壤团聚体中大部分是机械稳定性团聚体;3种植被类型土壤水稳性团聚体有机碳含量不同,乔灌木混交林有机碳含量高于灌木和乔木,且表层土壤≥5 mm团聚体有机碳含量高于其他粒径。藏东南林线过渡带土壤有机碳含量具有明显的“表聚效应”,大团聚体稳定性高有利于固碳;湿筛条件下破坏了土壤中非水稳性团聚体,其土壤大团聚体含量较干筛低,为高海拔地区土壤碳迁移研究奠定基础。To investigate the particle size distribution,structural stability and organic carbon distribution characteristics of soil agglomerates in the timberline transition zone in southeast Tibet,the forest line transition zone of Sejila Mountains was used as the research area in this study.The content of organic carbon was determined by potassium dichromate external heating method,and the content of aggregates was determined by dry sieving method and wet sieving method.The results were as follows,the contents of soil non-water-stable aggregates of the three typical vegetations in the timberline plots were quite different,most of which were aggregates with soil particle size≥0.25 mm.Compared with the non-water-stable aggregates,the content of water-stable aggregates with a particle size of<0.25 mm was higher,and the content of aggregates with a particle size of≥0.25 mm was lower.The MWD and GMD values measured by the dry sieving method were much larger than those measured by the wet sieving method,which indicated that the soil agglomeration most of the aggregates were mechanically stable aggregates.The organic carbon content of soil water-stable aggregates in the three vegetation types was different,with the organic carbon content of mixed trees and shrubs being higher than that of shrubs and trees,and the organic carbon content of≥5 mm aggregates in the surface soil was higher than that of other grain sizes.The soil organic carbon content had an obvious"surface aggregation effect",and the high stability of large aggregates was conducive to carbon sequestration.The non-water-stable aggregates of soilwere destroyed under wet sieving conditions,and the content of soil macro agglomerates was lower than that of dry sieving,which layed the foundation for the study of soil carbon transport in high altitude areas.

关 键 词：高山林线 土壤有机碳 土壤团聚体 载体 

分 类 号：S157.1[农业科学—土壤学]