这种肥皂含有天然钾盐，对皮肤很温和。

This soap contains natural ___potash, which is gentle on the skin.

农夫们用木灰制成的粗钾碱来给土壤增加养分。

Farmers used ___potash made from wood ashes to enrich the soil.

这家工厂主要生产用于农业的钾肥。

This factory mainly produces ___potash for agricultural use.