中文摘要：

运用磁感式大地电导率仪EM38及其移动测定系统，结合非参数地质统计学的单元指示克立格方法，对黄河三角洲地区200hm^2典型地块上两个比较关键季节的土壤盐分进行空间变异性的分析，给出了同一区域不同时段土壤盐分满足一定标准的条件概率图。结果表明，土壤表观电导率与盐分呈极显著相关性；各时段土壤表观电导率均呈近似的对数正态分布，且存在特异值；各时段土壤表观电导率的指示半方差均较符合球状套合模型；结构性因素导致秋季时段土壤盐分的空间变异性呈各向同性；随机性因素使春季时段土壤盐分的各向异性增强，尤其在南北、东西方向。由不同季节时段土壤盐分风险概率图看出，研究区土壤盐渍化程度总体较高，旱季条件下土壤盐分的表聚型是导致该现象最主要因素。电磁感应仪与指示克立格方法的结合运用为不同尺度（从农田到区域）上土壤调查与质量评价提供了新的途径，并为农业水土资源的决策管理提供指导。

英文摘要：

With the aid of an electromagnetic induction gauge （EM38） and its mobile sensing system, spatial variability of soil salinity was analyzed in a field （200 hm^2 ） typical of the Yellow River Delta for two critical seasons by using the univariate indicator Kriging procedure, and a soil salinity probability map at two different periods plotted based on the chosen criteria. Results indicate that apparent soil electrical conductivity is significantly correlated with salinity, and follows approximately the pattern of logarithmic normal distribution with some outliers in both seasons. Nested spherical models are fitted for indicator semivariance of the apparent soil electrical conductivity in both periods. Structural factors lead to isotropic spatial variability of soil salinity in autumn, while stochastic factors enhance anisotropy of soil salinity in spring, especially in the directions of north-south and east-west. Soil salinity probability maps in different seasons show that the extent of soil salinization is generally high in the study area, and surface accumulation of soil salts during the drought season is the primary reason for this phenomenon. The joint application of the electromagnetic induction gauge and the indicator Kriging method provides a new approach to survey and quality evaluation of soil resources at different scales ranging from farms to regional levels, and reference in decision making for and management of agricultural water-soil resources.