Characteristics and spatial variability of saline soil in desert-wet ecosystem area，Gansu Province, China

The Dunhuang Xihu National Nature Reserve is located in the extreme arid area of Northwest China, with a special desert-wetland ecosystem. The problem of soil salinization in this area is prominent and the related researches are very rare. The Harazi section of the reserve has not yet been examined. Based on detailed investigation and sampling and detecting of the reserve, the characteristics and spatial variability of soil salinity at the depth of 0 to 120 cm are studied by the combination of traditional statistics and geostatistics, which fills the research gap in this area. The result shows that the soil salt content decreases with the increasing depth, and it is obviously characterized by surface aggregation. The types of soil salinization are medium saline soil and heavy salt soil. The chemical types are sulfate chloride and chloride sulfate types. The soil salt content is generally of moderate variability. Dominated by structural factors, the soil salt content shows a spatial correlation of moderate to strong intensity. The salt content of the surface soil has obvious spatial distribution and variation pattern, and it generally shows the characteristics of low in the southwest and high in the northeast. The natural factors affecting the spatial variation in soil salinity in the study area include the extreme arid climate, groundwater table depth, distance far from rivers, topographic conditions and soil texture types. The results can provide a scientific basis and reference for soil salinization control and ecological environmental protection in this type of area.