伊犁河谷盐渍化区土壤盐分离子的空间变异特征

摘要

Geostatistics combined with GIS was applied to collect 60 samples and analysis was made of the spatial variability of soil salt (total salt, Ca2+, Mg2+, K+, Na+, SO42-, Cl-, CO32- and HCO3- ) in top soil (0 ～20 cm)from about 400 km2 of typical saline soil of study area in the Yili River Basin. The results indicated that the total salt,Ca2+ and HCO3- showed a normal distribution, and the others a lognonnal distribution. The chemical analysis of semivariograms indicated that the total salt was best described by spherical model, Mg2 + , K+, Na+, Cl-, SO42- , C032and Ca2 + were best described by Gauss model, and HCO3- showed pure nugget effect. The ranges of soil salinity were from 3.5 ～ 22.1 km. The spatial variability of all soil salinity ions were mainly produced by structural factors and random factors. The results also showed that except HCO3 -, the spatial correlation of other tested parameters, were moderately dependent, but their spatial heterogeneity degree was different. The Kriging method was applied to estimate the unobserved points and then the precise contour maps were obtained. By this way, the spatial variability of soil salinity ions could be reflected directly.%利用地统计学,结合地理信息系统(GIS),在面积约为400 km2的伊犁河谷典型研究区总共布设了土壤取样点60个,测定土壤表层(0～20 cm)总盐分及其组成(Ca2+、Mg2+、K+、Na+、SO42-、Cl-、CO32-、HCO3-)的空间变异性规律.结果表明:总盐分,Ca2+,HCO3-为正态分布,其余盐分离子符合对数正态分布;变异函数分析得出总盐分符合球状模型,Mg2+、K+、Na+、Cl-、SO42-、CO32-、Ca2+符合高斯模型,而HCO3-则是纯块金效应;盐分离子的变程在3.5-22.1 km之间;除了土壤总盐分(强烈自相关)其余盐分离子均表现为中等强度的空间自相关,但程度有所差异.用Kriging插值法对未测点的盐分离子进行最优估计,绘制含量分布图,从而可以更直观地反映研究区土壤盐分离子的空间变异特征.