Nitrogen and phosphorus: nutrients or pollutants?

Nitrogen (N) and phosphorus (P) are two of the main nutrients of plants. Fertilisers provide agricultural crops with nutrients. If more nitrogen or phosphorus fertilisers are used than the plants can absorb, they find their way into the environment and become potential pollutants. Today fertilisers are used more efficiently and are more targeted to plants' needs than 15 to 20 years ago. Despite improvements, however, the balance is not even. In 2012, the balance showed an average annual surplus of still 57 kg of nitrogen per hectare of agricultural area (including summer pastures). The phosphorus surplus was 2 kg per hectare.