nitrate
n[U, C]
salt formed by the chemical reaction of nitric acid with an alkali, esp potassium nitrate or sodium nitrate, used as fertilizers 硝酸盐; (尤指作肥料用的)硝酸钾, 硝酸钠
soil enriched with nitrates 施硝酸盐肥料的土壤.
A burst of activity associated with the laying of submarine cables soon confirmed the Challenger's observation that many parts of the ocean were two to three miles deep,