ni·tro·gen cy·cle
noun/ˈnaɪtrədʒən saɪkl/
/ˈnaɪtrədʒən saɪkl/
[countable, uncountable]- the processes by which nitrogen is passed from one part of the environment to another, for example when plants decay (= become destroyed by natural processes)
氮循环（各种形式的氮在自然界的循环）