8.2.B.6

The nitrogen cycle involves several steps, including nitrogen fixation, assimilation, ammonification, nitrification, and denitrification. These steps are performed by microorganisms in the soil. The largest reservoir of nitrogen is the atmosphere. In nitrogen fixation, nitrogen gas ( ) N2 is fixed into ammonia ( ) NH3 , which ionizes to ammonium (NH ) + 4 by acquiring hydrogen ions from the soil solution.