基于CT扫描研究青海湖流域高寒草甸不同坡位土壤大孔隙结构特征  

Soil Macropores of Alpine Kobresia Meadow in Different Slope Positions in the Qinghai Lake Watershed

作　　者：胡霞[1,2] 李宗超[1,2] 刘勇[1,2] 孙贞婷[1,2] 吕艳丽 

机构地区：[1]北京师范大学环境演变与自然灾害教育部重点实验室,北京100875 [2]北京师范大学减灾与应急管理研究院,北京100875

出　　处：《土壤》2016年第1期180-185,共6页Soils

基　　金：国家自然科学基金项目(41471018);国家自然科学基金重点项目(41130640)资助

摘　　要：以青海湖流域的高寒草甸土壤为研究对象,对该高寒草甸的坡上、坡中和坡下土壤分别取原状土柱进行CT扫描,利用Fiji软件分析土壤大孔隙结构特征的差异。结果表明：坡位对土壤的大孔隙结构有较大影响,坡上土壤的大孔隙数量、大孔隙度和大孔隙等效直径均大于坡中土壤,坡中土壤的大孔隙参数大于坡下土壤,坡上土壤的平均大孔隙度是坡中和坡下土壤的15.5和46.5倍。坡上土壤的大孔隙主要分布在150~400 mm土层深度,而坡中土壤的大孔隙主要分布在0~150 mm深度,坡下土壤的大孔隙主要在0~200 mm深度分布。坡上和坡中土壤的大孔隙形成主要是在土壤团聚体的作用下形成,植物根系在坡下土壤的大孔隙形成中占主导作用。The objective of this study is to quantify macropore structures of Alpine Kobresia meadow soils in different slope positions in the Qinghai Lake Watershed. A total of nine soil cores（0–50 cm deep） were taken respectively at the upper-slope, mid-slope and lower-slope sites with 3 replicates in each site, and the cores were scanned with a GE HISPEED FX/I medical scanner. Numbers of macropores, macroporosities and macropore equivalent diameters were interpreted by using X-ray computed tomography. The results indicated that slope position could significantly influence soil macropores. Soils on upper-slope had greater macroporosity, deeper and longer macropores than other two sites. Macroporosity was 15.5–46.5 times greater in soils on upper-slope than other two sites, and macropores were distributed mainly in the 150–400 mm layer, but mainly in the 0–150 mm and 0–200 mm soil layer in the mid-slope and the lower-slope, respectively. The form of macropores in lower slope can be attributed to root growth and decay, while can be attributed to aggregate function in the upper and middle slopes.

关 键 词：高寒草甸 坡位 大孔隙 青海湖 根系 

分 类 号：S157.1[农业科学—土壤学]