基于EM38长江河口地区土壤盐渍化特征研究

Study the Soil Salinization Character of the Yyangtze River Estuary Area with An Electromagnetic Induction EM 38

运用电磁感应仪EM38,结合GIS技术和地统计方法对长江河口地区土壤含盐量的空间变异性进行研究。结果表明:EM38所测土壤表观电导率与土壤电导率(EC1∶5)的相关系数均达到1%显著水平,其中以EMh+EMv为自变量的多元回归方程的拟合效果最好。盐分含量统计特征表明,土壤盐分含量变幅较大,且随着深度的增加变化幅度逐渐减小,各层土壤盐分含量均值介于0.7136～0.8137g/kg之间,且随着深度的增加盐分含量均值逐渐增大,总体上盐分分布具有一定的底聚性;各土层含盐量均呈现中等变异强度,变异系数相差较大,在水平方向上含盐量的变异随深度的增加而逐步趋弱。盐分含量空间分布表明,各层土壤盐分含量由南向北、自东向西有逐渐降低的趋势,随着深度的增加土壤含盐量不断升高。盐化土面积百分比表明,该地区大部分为非盐化土,轻度盐化土和中度盐化土所占比例较小,但由于含盐母质和地下水矿化度两个主要因素的影响,土壤盐渍化的发生存在巨大的潜在性威胁。运用EM38测值解译所得土壤盐分含量真实地反映了研究区的土壤盐渍化状况,为该地区土壤盐渍化的改良及防范提供依据。

Electromagentic induction EM38 was applied to study the spatial variability of soil salinity with the help of GIS and geostatistics,which was performed in typical sectors of Yangtze river estuary. The results showed that the related coefficient of apparent electrical conductivity（EM38） and soil electrical conductivity（EC1∶5） all achieved 1% significance level,and the best multiple regression equation was EMh＋EMv as independent variable in the three equations. Statistical characterization of salinity showed that amplitude was large of soil salinity and with the depth increasing the amplitude diminishingly,the means of six layers salinity between 0.7136 g/kg and 0.8137 g/kg,and with the depth increase the soil salinity rise,as a whole the salinity distribution possessed inverted salinity profiles. The soil salinity present moderate spatial variability,and the coefficient of variation varied large in different layers,in horizontal direction the soil salinity decrescendo with the depth increase. Soil salinity spatial distribution showed that the salinity had the trend of gradually reduce from south to north and east to west,and with the depth increase the soil salinity constant rise. The proportion of area percentage of soil salinity showed the majority of the area was desalinized soil,the proportion of light and moderate salinized soil were small,because of the saliferous parent material and groundwater salinity influence,the soil salinization occur hadpotential threat. Applied the apparent electrical conductivity interpreted the soil salinity,the result truly reflected the study area soil salinization condition,the study provided basis material for improvement and precaution the soil salinization.