## 1 Introduction  
Soil, as a natural carrier of history, is influenced by climate, topography, irrigation, fertilization, groundwater environment, and other factors, and has complexity and spatio-temporal variability, and its variability with spatial location is known as the spatial variability of soil [1]. This property of soils belongs to the regionalized variables, which differ from purely random variables, but are specific values of random variables at defined locations in the domain and are location-dependent random functions [2]. For this property of soils, geostatistics has long proved to be one of the most appropriate methods to solve the above problem, as it reveals the anomalies and correlations of soil properties on certain scales [3]. To some extent, the spatial variation in soil salinity reflects the degree and state of soil salinization in the soil tillage layer. Understanding its variation is of great significance for guiding people to carry out irrigation and drainage according to the law of variation and the dynamics of soil salinity, formulating measures to prevent and control soil salinization, ensuring soil quality, and improving agricultural output [4; 5; 6]. In recent years, more and more scholars have studied the spatial variability of soil salinity. [PERSON] et al. studied the law of distribution of soil pH and salinity in the northern coastal area of Iran by geostatistics [7]; [PERSON] et al. studied the spatial variation characteristics of soil salinity in the Ardakan region of central Iran [8]; [PERSON] et al. analyzed the spatial variation of soil salinity in the field of eastern Hungary [9]; [PERSON] studied the spatial distribution of properties of soil salinity in the Doukkala irrigated plain of Morocco [10]; [PERSON] studied the effect of rainfall on spatial variability in soil salinity in the coastal of eastern China [11]; and [PERSON] analyzed the spatial variation in soil salinity of palm groves in the Algerian plain [12]. Most of the above studies focused on coastal and plain areas, and the research objects were mainly field scale, with a relatively small portion of the research on the spatial heterogeneity of soil salinity in arid areas. With the development of oasis-intensive agriculture in the Weigan River Basin, people's management of farmland has been gradually improved, and irrigation and drainage facilities have been continuously improved, so that salinization in the study area has been mitigated and salt has been gradually shifted from the inner part (i.e., cultivation area) to the edge of the oasis, which has further aggravated the degree of salinization of the lower reaches of the basin and the oasis edge (i.e., desert-oasis ecotone). Its development has seriously threatened human production and life, as well as the ecological security of the basin [13; 14]. Therefore, soil salinization control has become important in managing the oasis. The scientific governance and utilization of soil salinity is based on a correct understanding of the spatial variability of regional soil properties [15; 16]. Therefore, in order to avoid further soil degradation, ensure sustainable development of agriculture, and maintain ecological security of the basin, it is necessary to analyze the spatial variation characteristics of soil salinity in the Weigan River Basin oasis. Through field sampling and indoor testing, the spatial variation properties of soil salinity in the layers between 0 m and 0.25 m, between 1 m and 2 m, and between 2 m and 3 m in the Weigan River Basin oasis were quantitatively studied using the methods of traditional statistics, geostatistics, and GIS. The specific objectives include: (1) descriptive analysis of soil salinity. Traditional statistics were used to summarize the overall situation of soil salinity and assess the rationality of the number of samples. (2) Estimation of spatial variability. The spatial heterogeneity of soil salinity at different depths was analyzed using geostatistical theories and methods. (3) Digital mapping of soil salinity.