Your neighbor faithfully applies fertilizer to his lawn to ensure beautiful healthy green grass. Explain how your neighbor's fertilizing habit affects at least one nutrient cycle

Nutrient cycle is the exchange of organic and inorganic matter between physical environment and living organisms.

Hence, when the neighbor is applying fertilizers, then he is giving essential providing macro nutrients (phosphorous, nitrogen and potassium) to the soil. But soil will have both micro and macro nutrients in balance. Excess macronutrients will reduce micronutrients availability, as plant may not be using all the nutrients supplied by the neighbor. This will cause the accumulation of nitrogen in the soil thus affecting the nitrogen cycle (nitrogen cycle is one of the Earth's biogeochemical cycles). Plants will get nitrogen from soil and bacteria will convert it to a usable form, but readily available excess nitrogen will allow the growth of weeds, and washing of these nutrients will create eutrophication situation. In usual cases plants absorbs nitrogen in the form of nitrates and bacterial also converts ammonium into nitrates, the denitrifying bacteria converts this nitrate to nitrites and nitrogen gas. The excessive availability of nitrogen from fertilizer will disturb the balance of nitrogen available in the soil.