potassium nitrate

例句：

1. 1.Potassium nitrate is a common chemical used in fertilizers.
   硝酸钾是一种常见的化肥原料。
2. 2. The potassium nitrate was added to the soil to improve its fertility.
   向土壤中添加硝酸钾以提高其肥力。
3. 3. The plant needs potassium nitrate to grow strong and healthy.
   植物需要硝酸钾来生长强壮健康。