These are obviously different from other delta region and foothill region, how is the underwater element so special if t这和其他的三角洲和丘陵地区相比很不一样，如果没有天外来客，此地的地下水体元素成份怎会如此特殊？
Coupling relationship between species diversity of plant communities and soil factors in foothill belt of arid area干旱区山麓带植物群落特征指数与土壤因子关系初探