为了探索民勤绿洲天然胡杨林下土壤盐分特征及其随时间的变化规律，为保护干旱地区胡杨林的生态环境提供可靠依据，应用地统计学与经典统计学的方法，研究绿洲天然胡杨林下土壤盐分的垂直变化特征及生长季期间的变化规律。结果表明：研究区天然胡杨林下土壤全盐含量在0.55%~3.42%之间，土壤全盐量变化趋势总体表现为随深度增加而减小，且以0~40 cm的变化趋势最为显著，在80~120 cm较为稳定；表层和亚表层的土壤全盐含量较高，其中JHCD、SWCD、SCKD表层土壤含盐量的平均值分别达到1.54%、2.80%、1.11%。土壤全盐含量在胡杨生长季节上的变化总体表现为：春季＞夏季＞秋季。不同树龄胡杨林下的土壤全盐含量不同，表现为中年阶段＞成熟阶段＞老熟阶段，SWCD不同树龄胡杨林土壤全盐含量的差值略大。采样点土壤全盐量的变异性属于中等变异，土层越深，土壤全盐量变化程度相对较小。

In order to explore the soil salt characteristics of natural Populus euphratica in Minqin oasis and the changing of the soil salt characteristics with time, as arid the protection of the ecological environment to provide reliable basis. The author used traditional statistics and semivari-ance analysis of geostatistics for studying on temporal variability of soil salt and it’s regulation during the Populus euphratica growth season in Minqin oasis. The results showed that soil salt content under the natural populus euphratica forests was between 0.55%-3.42%. Soil salt content of the study area increased with depth in vertical direction and the most obvious soil layer was the 0-40 cm, while 80-120 cm soil layer was steady. Soil salt content of the surface soil and subsurface soil was higher. The average value of surface soil salt content in JHCD, SWCD, SCKD was respectively 1.54%, 2.80%, 1.11%. Soil salt content of the natural Populus euphratica forests in the growing season was different. It was found that soil salt content of the spring was the highest, which was followed by the summer and autumn. Soil salt content of the natural Populus euphratica in middle-aged stage was bigger than the mature stage, while soil salt content of the mature stage was bigger than the overripe stage. The difference value between different year-old Populus euphratica was bigger in the SWCD. The variation efficient of soil salt content in Minqin belonged to middling variability and it decreased gradually with the depth in vertical direction.