How does the use of fertilizer affect the nitrogen cycle

It don’t

Explanation:
We might think that adding specific nitrogen compounds to agriculture would affect the nitrogen cycle. But, it really is just a part of a much larger system as shown by the included graphics.
As a "cycle" the nitrogen is continuously removed from the atmosphere and ground sources, used by plants for growth, and then fixed, immobilized or leached or removed back to the soil or atmosphere.

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce

The category is the thing that is most simmilar throughout a period