Five Priorities for Managing Nitrogen Pollution

Nitrogen (N) is an essential element for all life forms. It acts as the building blocks of biomolecules including proteins and DNA – as well as chlorophyll – the green pigment that allows plants to capture light energy from the sun. In excess though, reactive nitrogen (known as Nr and including all chemical compounds of nitrogen except N₂) adversely affects the natural environment, ecosystems and human health. Emissions in the form of ammonia (NH₃) and nitrogen oxide (NOⅹ) contribute to particulate matter and acid rain while nitrous oxide (N₂O) is a potent greenhouse gas, over 300 times more effective at trapping heat in the atmosphere than carbon dioxide (CO₂). The adverse effects of Nr loss are most prevalent from nitrogen used in agriculture because more than 50 per cent of the nitrogen fertiliser applied to plants and more than 70 per cent of the nitrogen fed to livestock is lost to the natural environment, causing air and water pollution, growth of algae, and most famously, damaging the Great Barrier Reef. Managing nitrogen in agricultural production is key to achieving global food security with minimal degradation of ecosystems and impacts on human health. The challenge of managing excess nitrogen extends beyond farms and requires concerted efforts from a range of stakeholders. While varied metrics have been developed to inform different aspects of nitrogen management, few efforts have tried to combine nitrogen metrics to derive a coherent set of actions for each party that is involved and affected by the use and emissions of nitrogen. Our research proposes the ‘5 Ps’: Production, People, Planet, Policy and Partnerships as priorities to shape guidelines for sustainable management of nitrogen using multi-dimensional nitrogen metrics