nitrate
noun [ C or U ] uk/ˈnaɪ.treɪt/ us/ˈnaɪ.treɪt/
硝酸盐;硝酸盐肥料
a chemical that includes nitrogen and oxygen, often used as a fertilizer (= a substance that helps plants grow)
potassium/sodium nitrate 硝酸钾／钠
Nitrogen is converted into nitrates in the soil which plants can then use. 氮转化为土壤中的硝酸盐，可被植物吸收。