Final answer:
Nitrogen is the fertilizer element most concerning for the environment, as its excess can cause ecological disturbances like eutrophication. Phosphorus is also significant but to a lesser extent. Organic farming improves soil quality, aiding biodiversity and natural nutrient cycles.
Step-by-step explanation:
The fertilizer element of most concern environmentally is nitrogen. Synthetic fertilizers often have high amounts of nitrogen and phosphorus, because these elements are vital for plant growth, with nitrogen being a key component of proteins, DNA, and chlorophyll and phosphorus being required for the production of DNA and ATP. However, when there is an excess of these elements, it can lead to ecological disturbances such as eutrophication, where water bodies become overly enriched with nutrients, leading to excessive growth of algae and depletion of oxygen. Organic agricultural methods, which eschew the use of synthetic fertilizers, can improve soil quality through enhanced biodiversity and stronger biogeochemical cycles.