毛乌素沙地东南缘沙丘水分垂直变化规律及风蚀意义  

Vertical Distributions of Soil Moisture Contents of Three Types of Sand Dunes in Southeast of the Mu Us Sandy Land and Their Implications of Wind Erosion

作　　者：符超峰[1,2] 梅凡民[3] 赵景波[1] 

机构地区：[1]陕西师范大学旅游与环境学院,西安710062 [2]长安大学西部矿产资源与地质工程教育部重点实验室.西安710054 [3]西安工程大学环境与化学工程学院,西安710048

出　　处：《水土保持学报》2010年第6期105-110,116,共7页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(40872114,40975094);黄土与第四纪国家重点实验室开放基金(SKLLQG0806)

摘　　要：为了进一步揭示毛乌素沙地含水量垂直变化的规律和风蚀意义,通过野外调查、采样、含水量测定、沙粒粒度测定和计算模拟,系统地研究了毛乌素沙地东南缘的3类沙丘含水量垂直变化的趋势,模拟了含水量垂直变化对输沙率垂直差异和沙丘形态演化的影响。结果表明:裸露流动沙丘迎风坡含水量在1.33%～3.79%之间波动;背风坡含水量在0.39%～5.04%范围内波动;丘间洼地含水量在2.12%～6.36%之间波动,裸露流动沙丘含水量的垂直变化可分为自上而下的5个沙层。灌木覆盖沙丘迎风坡的含水量在0.74%～11.92%之间波动;背风坡的含水量在0.89%～12.08%之间波动;丘间洼地的含水量在1.34%～9.24%之间波动,沙丘含水量的垂直变化存在差异明显的3个沙层。人工乔木覆盖沙丘的相对输沙率介于裸露流动沙丘和灌木覆盖沙丘之间。沙丘含水量2%～3%的垂直变化就能引起沙丘形态演化。在含水量垂直变化和沙丘背风坡和丘间洼地的阻滞下,沙丘形态演化存在3个阶段。在沙尘暴预报过程中需要考虑沙丘形态、沙丘含水量的垂直变化等因素对输沙率的影响,以提高预报工作的精度和可靠性。In order to explore vertical distributions of soil moisture contents of sand dunes and to understand their effects on aeolian dunes forms,soil moisture contents of three types of sand dunes in southeast of the Mu Us sandy land were investigated.It shows that soil moisture content of bare migratory dunes in windward slope,leeward slope,and bottom ranges with depth around 1.33%～3.79%,0.39%～5.04%,2.12%～6.36% respectively.The vertical distributions of soil moisture contents can be divided into five sub-layers.Soil moisture content of shrubs-covered dunes varies with sand-layer depth more significantly than that of bare migratory dunes.Moisture content of shrubs-covered dunes in windward slope,leeward slope,and dune interval,fluctuates about 0.74%～11.92%,0.89%～12.08% and 1.34%～9.24%,respectively.The moisture content vertical distribution of shrubs-covered dunes can be classified as three sub-layers.The vertical fluctuation of moisture content of trees-covered dunes is between that of bare migratory dunes and that of shrubs-covered dunes.The vertical distribution of moisture content of three types of dunes depend on such factors as sand particles size,position and vegetation forms.According to modeling effect of moisture content on sand transport rate,sand transport rate in the trees-covered dunes fluctuates is between that of the bare migratory dunes and that of the shrubs-covered dunes.It could be estimated that vertical fluctuation of moisture content ranging about 2%～3% could induce evolution of an aeolian dune morphology if other factors affecting a dune form keep constant.Supposing that development of an aeolian dune is affected by moisture content and resistance of sand particles＇ movements from leeward slope and dune interval,evolution of a dune could have three stages.The findings imply that aeolian dunes forms and vertical variations of moisture contents should be included in present models of sand transport rate so as to improve precision and reliability of them.

关 键 词：沙丘 含水量 风蚀 毛乌素沙地 输沙率 

分 类 号：S152.7[农业科学—土壤学] S157.1[农业科学—农业基础科学]