Real Dictionary

nitrogen cycle in American English
the cycle of natural processes through which atmospheric nitrogen is converted by nitrogen fixation and nitrification into compounds used by plants and animals in the formation of proteins and is eventually returned by decay and denitrification to its ori
noun: the continuous sequence of events by which atmospheric nitrogen and nitrogenous compounds in the soil are converted, as by nitrification and nitrogen fixation, into substances that can be utilized by green plants, the substances returning to the air and s

nitrogen cycle in British English
noun: the natural circulation of nitrogen by living organisms. Nitrates in the soil, derived from dead organic matter by bacterial action, are absorbed and synthesized into complex organic compounds by plants and reduced to nitrates again when the plants and th