Abstract: Classical statistical and geostatistical methods were used to explore dynamics of soil salt and water during the growing season of natural Populus euphratica in Minqin Oasis.It was found  that soil water content increased with soil depth in Shuangcike and Suwu,but it increased first and then decreased with soil depth in Jiahe.In the study area,the soil water content in the 0-20 cm of soil was quite low,ranging between 8.5 and 34.0 g·kg^-1 and being 18.2 g·kg^-1 on average.It fell into the category of moderate in variability and in sptial correlation as well.And it also varied from season to season,showing a decreasing order of spring,autumn,and summer.The soil salt content in the study area was also in the category of moderate in variability and generally decreased with depth.The soil total salt content in the surface soil(0-20 cm)of Jiahe,Suwu and Shuangcike was 15.4,28.0 and 11.1 g·kg^-1,respectively on average.It also varied with the seasons,showing a decreasing order of spring,summer,and autumn.The diameter at breat height a Populus euphratica tree was negatively related with soil salt and water contents.

Key words: Minqin Oasis, Populus euphratica, soil water and salt content, variation coefficient