离心机法测定持水特征中的土壤收缩变化研究  

Soil Shrinking Change during Measuring Retention Characteristics by Centrifugal Method

作　　者：吕殿青[1] 王宏[1] 王玲[1] 

机构地区：[1]湖南师范大学资源与环境科学学院,湖南长沙410081

出　　处：《水土保持学报》2010年第3期209-212,216,共5页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(批准号:40801083);湖南省重点学科自然地理学项目(批准号:2008001);湖南省教育厅青年项目(批准号:09B061)

摘　　要：土壤收缩特征是精确定量评价土壤结构和水力特性的关键,对农业、城市压实土壤水分溶质运移有重要影响作用。本文通过离心机法测定了黄土高原典型3种原状和扰动土壤的持水特征,分析了测定过程中的收缩变化特征。结果表明:土壤持水特征测定中随着压力的增加,有效收缩度增大,其变化规律可用对数函数来描述;土壤收缩过程分为超正常段、结构段和伪饱和段3个阶段,适于用直线模型描述;在伪饱和段和结构段,收缩特征值小于1,土壤收缩主要受水分散失控制;在超正常段,收缩特征值大于1,土壤收缩受水分散失和外加压力控制,压力起主导作用;离心机和压力膜法测定土壤持水特征要考虑压力对土壤收缩变化的影响。Soil shrinking characteristics is the key of evaluating soil structure and hydraulic properties,and has important effect on water and solute transport in agriculture and city compacting soil.In the paper,soil retention characteristics were measured by using centrifugal method for three types of disturbed and undisturbed soils from loam to silt clay on the Loess Plateau.Soil shrinkage characteristics were analyzed.The results showed that effective shrinking distance decreased with the increase of pressure.Their change law may be described by logarithm function.Soil shrinkage process was divided into three stages of super-normal stage,structure stage and false saturated stage and described by line models fitly.Soil shrinkage characteristics values were less than 1 and soil shrinkage was controlled by water loss in the structure stage and false saturated stage.In the super-normal stage,soil shrinkage characteristics values were more than 1 and soil shrinkage was controlled by water loss and pressure whose action was main factor.Effect of pressure on shrinking change was specially considered in centrifugal and pressure membrane methods during measuring water retention.

关 键 词：持水特征 比容积 土壤收缩 

分 类 号：S152.7[农业科学—土壤学]