Question

how does the use of fertilizer affect the nitrogen cycle?

Explanation:

Fertilizers, especially nitrogen - based ones, add extra nitrogen to the soil. This can lead to an increase in nitrogen available for plants. However, excess nitrogen can leach into waterways (causing eutrophication) or be converted to nitrous oxide (a greenhouse gas) through denitrification. It disrupts the natural balance of the nitrogen cycle by bypassing some of the natural nitrogen - fixing processes (like those of nitrogen - fixing bacteria in the soil).

Answer:

The use of fertilizer, particularly nitrogen - rich fertilizers, disrupts the nitrogen cycle. It adds excess nitrogen to the soil. Some of this nitrogen can be leached into water bodies (causing eutrophication when it leads to excessive algal growth) or converted to nitrous oxide (a greenhouse gas) during denitrification. It bypasses some natural nitrogen - fixing steps (such as those carried out by symbiotic nitrogen - fixing bacteria in root nodules) and can lead to an imbalance in the availability of nitrogen for different organisms in the ecosystem.