荒漠-湿地生态系统区盐渍土特征及空间变异性

敦煌西湖国家级自然保护区地处西北极端干旱区,具有特殊的荒漠-湿地生态系统。土壤盐渍化问题突出且研究程度很低,保护区内的哈拉齐一带甚至为研究空白区。在对保护区进行详细调查以及采样测试的基础上,采用传统统计学与地统计学相结合的方法对0～120 cm深度内的土壤盐分特征及空间变异性进行了研究,填补了该区域的研究空白。研究结果表明:保护区内的土壤含盐量总体呈现随深度增加而降低的趋势,具有明显的表聚性特征;土壤盐渍化类型为中盐土和重盐土,化学类型为硫酸盐—氯化物型以及氯化物—硫酸盐型;土壤含盐量总体表现为中等变异性;受结构性因素主导,土壤含盐量总体呈现出中-强空间相关性;表层土壤含盐量具有明显的空间分布变化规律,总体呈现出西南低,东北高的特征。影响保护区表层土壤含盐量空间变化的自然因素包括极端干旱气候、地下水位埋深、与河流距离、地势条件以及土壤质地类型。研究结果可为该类型区域的土壤盐渍化防治及生态环境保护提供科学依据和参考。

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.