黄土高原不同土质和植被类型下Cl^(-)运移特征及影响因素  

Cl^(-) Transport and Its Influencing Factors in Soil as Affected by Soil Texture and Vegetation Cover in Loess Plateau

作　　者：李荣磊 陈留美 邵明安[1,4] 黄来明[2,5] 裴艳武 张应龙 LI Ronglei;CHEN Liumei;SHAO Ming’an;HUANG Laiming;PEI Yanwu;ZHANG Yinglong(College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China;Key Laboratory ofEcosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Resources and Environment,Zunyi Normal University,Zunyi,Guizhou 563006,China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences,Yangling,Shaanxi 712100,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China;Shenmu Ecological Association,Shenmu,Shaanxi 719399,China)

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [3]遵义师范学院资源与环境学院,贵州遵义563006 [4]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [5]中国科学院大学资源与环境学院,北京100049 [6]陕西省神木县生态协会,陕西神木719399

出　　处：《土壤学报》2021年第5期1190-1201,共12页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41601221);贵州省科技合作计划项目(黔科合LH字[2017]7068号);中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室项目(A314021402-2010)资助。

摘　　要：为确定不同土质和植被类型下溶质运移特征及影响因素,采用垂直土柱易混置换法,研究了陕北六道沟和圪丑沟流域不同土质(砂土S、壤土L)和植被类型(乔AR、灌SH、草GR)下Cl^(-)运移特征。结果表明:Cl^(-)初始穿透时间(TS:12~80 min)、完全穿透时间(TE:75~480 min)、平均孔隙水流速(V:0.52~1.98 cm·h^(-1))和水动力弥散系数(D:0.75~2.55 cm2·h^(-1))均随土壤质地、植被类型和土层深度而发生变化。0~20 cm土层Cl^(-)的TS和TE最小,随深度增加而增大,V和D则相反。同一质地不同植被类型条件下0~1 m剖面中Cl^(-)的V和D均值表现为:S-AR> S-GR> S-SH和L-AR> L-SH> L-GR,TS和TE则相反,这是由于砂土和壤土中不同类型植物根系生物量剖面分布具有显著差异,进而影响大孔隙数量、孔隙连通性密度和优先流路径。同一植被类型不同质地土壤0~1 m剖面中Cl^(-)的V和D均值表现为:S-AR> L-AR;S-SH> L-SH;S-GR> L-GR,TS和TE则相反,这是由于土壤机械组成影响孔隙分布状况,砂土中大孔隙数量多且孔隙连通性密度高,有助于形成优先流,而壤土中细小孔隙所构成的复杂孔径及带电团聚体对离子的吸附作用会阻碍Cl^(-)运移。容重、大孔隙数、孔隙连通性密度、有机碳含量和颗粒组成均与V,TS和TE显著相关,表明土壤性质显著影响不同土质和植被类型下Cl^(-)运移特征。上述结果可为黄土高原不同质地土壤人工植被合理布局与配置,降低养分流失风险,提升生态系统服务功能提供参考。【Objective】To evaluate nutrient cycling and pollutant migration in the Earth’s Critical Zone,it is essential to understand solute transport in soils.Despite extensive studies on processes and mechanisms of solute transport,little is known about how to characterize and regulate solute transport in soils different in soil texture and vegetation cover.This study is oriented to investigate Cl^(-) transport parameters and their influencing factors in typical sandy and loamy soils different in vegetation cover in the Liudaogou and Gechougou watersheds in the northern part of the Loess Plateau.【Method】Six undisturbed soil columns(7 cm in diameter and 25 cm in height)different in texture(sandy and loamy,abbreviated as S and L,respectively)and in vegetation cover(arbor,shrub and grass,abbreviated as AR,SH and GR,respectively)were collected by hand to keep it as intact as possible in the Liudaogou and Gechougou watersheds located in Shenmu City,Shaanxi Province.With these columns,an indoor experiment was carried out to determine Cl^(-) penetration curve in each soil column and experiment data were simulated with the convection-dispersion equation.Cl^(-) transport parameters,including time the penetration begins(TS),time the penetration ends(TE),average pore-water velocity(V)and hydrodynamic dispersion coefficient(D),were obtained with the aid of the CXFIT software.Relationships between soil properties and Cl^(-) transport parameters were analyzed with Pearson’s test.【Result】Results show that TS,TE,V and D of Cl^(-) all varied with soil texture,vegetation type and soil depth in the range of 12–80 min,75–480 min,0.52–1.98 cm·h^(–1) and 0.75–2.55 cm2·h^(–1),respectively.TS and TE was the lowest in the 0–20 cm soil layer and increased with increasing soil depth,while V and D both exhibited a reverse pattern.Mean V and D in 0–1 m soil profiles the same in texture varied with vegetation cover,showing a decreasing order of S-AR>S-GR>S-SH and L-AR>L-SH>L-GR,while mean TS and TE did too,but showing

关 键 词：Cl^(-) 穿透曲线 溶质运移 植被类型 土壤质地 

分 类 号：S152.3[农业科学—土壤学] S152.5[农业科学—农业基础科学]