莱州湾南岸重盐渍化区不同土壤盐分离子的分布特征

Distribution Characteristics of Different Soil Salt Ions in Severe Salinization Regions in the Southern Coastal Area of Laizhou Bay

针对莱州湾南岸重盐渍化土地复垦利用过程中存在的土壤盐碱、瘠薄等障碍问题,选择重盐渍化区的典型地块作为研究对象,运用地统计学和GIS技术,研究不同土壤盐分离子的空间变异性及其相关关系,并绘制各盐分离子的空间分布图。结果表明:不同深度的土壤盐分离子质量浓度变幅差异较大,最大达到124.34mg·L(-1);各土壤盐分离子质量浓度随着土壤深度的增加而增加,变异系数为10%～100%,属于中等强度变异。偏相关分析结果表明各盐分离子间的相关关系复杂;聚类分析将各盐分离子分为3类:第一类包括TS,σ,TDS,SO_4^(2-),Mg^(2+),K^+,Na^+,Cl^-和Ca^(2+),第二类包括SAR和Cl^-/SO_4^(2-)比值,第三类主要是NO_3^-。各盐分离子的块基比均小于25%,具有强烈的空间相关性,表明盐分离子的空间分布主要受结构性因素影响;空间自相关距离为87.88～215.57m,均大于取样间距40m。克里格(Kriging)插值结果表明:研究区土壤含盐量呈明显的带状分布,土壤含盐量从东北部往西南部逐渐增加,东南部土壤含盐量最高;研究区土壤碱化程度较低,盐渍化类型主要为硫酸盐型。该研究为莱州湾南岸重盐渍化区盐渍土的分区、改良、管理和合理利用提供了理论基础和参考依据。

The southern coastal area of the Laizhou Bay has been one of the most severest area affected by soil salinization.In view of the obstacle problems(e.g.,soil salinization,poor soil quality,etc)in the reclamation process of the abandoned salt pan,this study selected this severest salinization area as research targeted region,and used geostatistics and GIS technology to study on the spatial variability and the correlativity of different soil salt ions and to visually present the spatial distributional patterns of the salt ions.Results showed that the soil salt ion contents varied greatly at different depths and the maximum value was 124.34 mg·L-1.The content of each salt ion increased with the depth,and the range of the variation coefficient was 10%~100%,which belonged to moderate variation.The partial correlation analysis showed complex correlations among the salt ions.The salt ions can be divided into three categories by cluster analysis.The first category included TS,EC,TDS,SO^2-4,Mg^2+,K^+,Na^+,Cl^-,and Ca^2+,the second category were SAR and Cl-/SO 2-4,and the third category was mainly NO-3.The nugget/sill ratio of all the salt ions was less than 25%,indicating a strong spatially correlation.And,the spatially distribution of salt ions was mainly affected by structural factors.The spatial autocorrelation distances ranged from 87.88 m to 215.57 m,which were all longer than the sampling interval(40 m).As shown by the results of Kriging interpolation,the spatial distribution of soil salinity in the study area took on an apparent strip style,soil salinity increased from northeast to southwest sides,and the highest soil salinity was observed in the southeast side.The degree of soil alkalization was low,and sulfate type was the primary salinization type.This study provides some theoretical basis and references for the partition,amelioration,management and rational utilization of saline soil in the severe salinization regions in the southern coastal area of the Laizhou Bay.