There are two issues relating to the state of the phosphorus-nitrogen cycle. Both elements are essential to plant and animal life. But one of the problems is that phosphorus, which is used as a fertilizer for fields and lawns is in limited supply, and that supply is geopolitically concentrated. Nearly 90% of all known phosphorus reserves are found in just three countries – the vast majority is in Morocco, with China, Algeria coming in next.
The second issue is that the excess of phosphorus-based fertilisers that drain from fields and lawns into neighbouring lakes can have disastrous effects on the surrounding water. It can lead to the sudden growth of algae that can cause the decline or death of other lake organisms and produce toxins that are dangerous to people or animals that swim in the lake or get drinking water from it