# What is the importance of nitrogen fixation?

Nitrogen fixation is a process whereby bacteria in the soil convert atmospheric nitrogen (${N}_{2}$ gas) into a form that plants can use.
The reason this process is so important is that animals and plants cannot use atmospheric nitrogen directly. That ${N}_{2}$ gas is very abundant (78% of the atmosphere) but it must be converted into another form before most organisms can use it. Bacteria convert it into ammonium ( $N {H}_{4} +$), which then plants can absorb. Animals get their nitrogen by eating plants or other animals.