摘要
土壤含水量和可溶解盐分浓度的测定,对了解土壤盐分的分布及移动具有重要意义。但如何在作物生长不同时期,对耕作区的土壤含水量及可溶解盐分浓度进行同时连续测量?是了解土壤盐分分布及动态变化规律的关键。该文将TDR测量的土壤含水量及体积电导率结合起来推算土壤溶液电导率及饱和溶液电导率,对黄河上游盐渍化农田的土壤水盐动态变化特征进行了相关分析,为土壤水盐动态研究提供了一种新的方法。研究结果表明,地下水位在年内总体埋深较浅,小于150 cm;10 cm深度土壤含水量在时间变化上呈现递减趋势,年内变化范围为20%～45%(不包括土壤冻融期),20,40,60 cm深度土壤含水量年内变化较复杂,波动范围为33%～50%,垂向分布表现为下层高于上层;与土壤水分相反,土壤盐分表现为上层高于下层。在整个作物生长季节,土壤10 cm深度的ECw和ECsat多数时间分别在10～15 dS/m和5～10 dS/m范围内波动,高于盐化和非盐化土壤分类标准4 dS/m。土壤20,40 cm深度的盐分变化规律同样较上层10 cm复杂,盐分浓度在时间序列上呈现出大小交替变化的特点。
The movement of soluble salts in soil is directly related to the movement of soil water,therefore,how to simultaneous and continuous determine the soil water and soluble soil salt content in cultivated soil layer,which is key for understanding the distribution of soil salinity and dynamic variation law.This paper combined soil water content and soil bulk electrical conductivity measured by Time Domain Reflectometry continuously,to calculate electrical conductivity of soil solution（ECw） and electrical conductivity of saturated soils solution（ECsat）,both are closely related to soil soluble salt concentration,then analysis the dynamic change feature of soil water and salt,which is a new method.The analysis results indicated that groundwater level kept low value in one year,low than 150 cm.Soil water content in 10 cm decreased with time in our observation periods（except the soil frozen-thaw time）,ranging from 20% to 45%.The variation character of soil water in 20,40,60 cm,which range from 33% to 50%,were relatively complicated.Vertically,soil water content was high in upper layer than in lower layer.Contrary to soil water,soil salt content appeared decreasing trend from the soil surface layer to deeper layer.In the most time of crop grown season,the ECw and ECsat in 10 cm fluctuated respectively in range of 10～15 dS/m and 5～10 dS/m,high then the classification criteria 4 dS/m between saline soil and non-saline soil.Compared with the soil salt change rule in 10 cm,it was still complex in 20,40 cm,which characterized by alternating high and low values.
出处
《水土保持学报》
CSCD
北大核心
2010年第3期80-84,共5页
Journal of Soil and Water Conservation
基金
国家重点基础研究发展计划项目(2009CB421305)
国家自然科学基金项目(40875006)
中国科学院西部行动计划项目(KZCX2-XB2-09-01)
欧盟第七框架项目CEOP-AEGIS(FP7-ENV-2007-1Grantnr.212921)
关键词
TDR
电导率
土壤含水量
土壤盐分
TDR
electrical conductivity
soil water content
soil salt
