A government-commissioned group of experts, including Professor Mark Sutton of the UK Centre for Ecology & Hydrology, has made recommendations on minimising pollution from the use, manufacture, storage and distribution of nutrients in agriculture.
Inefficiencies in farming practices mean that most of the nutrients within animal waste and synthetic fertilisers, which are applied to farmland to boost crop growth, leach into the environment. Nitrogen, through its many forms, is an air or water pollutant or greenhouse gas, while phosphorus can also end up in nearby lakes and rivers through run-off, reducing water quality.
The Department for Environment, Food and Rural Affairs (Defra) therefore set up the Nutrient Management Expert Group (NMEG) to find ways to mitigate the impacts on public health, biodiversity and climate change, while also considering the need for food production. It comprised agricultural policy experts, agronomists, scientists and economists, and was led by Professor Janet Dwyer of the University of Gloucestershire.
In their newly published report, the group members recommended the Government develops a national Nutrient Management Action Plan in partnership with key sectors. They said this should combine:
- more effective regulation with detailed monitoring
- more comprehensive and coordinated advisory services that support nutrient budgeting and planning at farm level
- the encouragement of investment in efficient nutrient recycling across agriculture and the wider food system.
Since the NMEG was commissioned in 2020, fertiliser prices have tripled, highlighting the urgency of taking action on economic as well as environmental grounds.
Professor Sutton estimates the amount of nutrient wasted in the UK agri-food system is worth the equivalent of at least £1 billion a year, at current fertiliser prices. He says: “It is important to recognise that nutrients are not always a good thing. Farming systems are extremely leaky. Nutrient pollution is bad for air and water quality, biodiversity, human health and climate change, as well as being a massive waste of resources.
“The billion-pound-a-year question is how to stimulate uptake of the best measures, benefiting the environment and economy at the same time. Our report for Defra identifies a wealth of opportunities for further discussion with government and others.”
The report of the Nutrient Management Expert Group, titled Improving policy and practice for agricultural nutrient use and management, is available via gov.uk
About nutrient pollution
NITROGEN has many forms with multiple impacts in the environment:
- Gases such as ammonia (NH3) and nitrogen dioxide (NO2) are key components of particulate matter, thereby contributing to poor air quality which can aggravate respiratory and heart conditions, leading to premature deaths
- These gases can also cause a decline in the biodiversity of lichens, mosses and other sensitive flora, either by killing species directly or allowing nitrogen-tolerant plants to out-compete them. This results in negative knock-on impacts on animals who reply upon these species for food or shelter.
- Nitrate from chemical fertilisers, manure and industry pollutes rivers, seas and soils posing a health risk for humans, fish, coral and plant life
- Nitrous oxide (N2O) is a greenhouse gas that depletes the ozone layer and is 300 times more powerful than carbon dioxide.
PHOSPHORUS, present in animal and human excreta, enters water courses through agricultural runoff and sewage pollution. The nutrient accelerates the growth of algal blooms which produce toxins that are harmful to animals and humans who come into contact with or consume contaminated water.