How have humans altered the nitrogen cycle?
Unfortunately, human activity has altered the cycle. We do this by adding nitrogen into the soil with fertilizer as well as other activities that put more nitrous oxide gas into the atmosphere. This adds in more nitrogen than is needed by normal cycle and upsets the cycle's balance.
Fun Facts
Around 78% of the atmosphere is nitrogen. However, this is mostly not usable by animals and plants.
Nitrogen is used in fertilizer to help plants grow faster.
Nitrous oxide is a greenhouse gas. Too much of it can also cause acid rain.
Nitrogen has no color, odor, or taste.
It is used in many explosives.
About 3% of your body weight is nitrogen.