Our current food systems are suffering from an addiction to nitrogen. Global use of nitrogen fertiliser has grown exponentially with projections that it will reach a total of 118 million tonnes by 2020. The UK’s addiction is significant, and this dependency is causing catastrophic damage to the environment and public health. Without serious corrective measures, nitrogen pollution could push the planet to breaking point.
While agriculture is not the only contributor to nitrogen pollution (transport and energy generation also produce substantial amounts), it is the primary source and is responsible for approximately two-thirds of reactive nitrogen emissions. The agricultural emissions of reactive nitrogen derive from two major sources: artificial fertiliser and animal waste. Of the 88% of ammonia emissions that agriculture is responsible for, nearly half are from cattle and a quarter are from fertiliser applications. The remaining 26% come from other livestock sources.
Over the last century, artificial nitrogen fertiliser has provided a straightforward and cost-effective method for farmers to boost productivity, fuelling agricultural intensification and the expansion of food production worldwide. As a result of these gains, governments have turned a blind eye to the significant negative impacts of the use of nitrogen fertiliser, choosing instead to prioritise the short-term goal of food security. However, it is becoming more and more obvious that we can no longer overlook the damage that our addiction is causing, particularly in connection to:
- Soil degradation resulting from exploitative crop rotations that rely on nitrogen fertilisers;
- Rising air pollution from ammonia and the formation of secondary particulate matter;
- Pollution of the upper atmosphere from greenhouse gases and ozone depletion;
- Loss of habitats and delicate plant species smothered by nitrophilic species;
- Dramatic declines in farmland birds, small mammals, pollinating insects, invertebrates;
- Eutrophication and acidification of rivers, lakes and marine coastal regions;
- Elevated nitrate levels in drinking water;
- Loss of marine and aquatic species due to dead-zones caused by run-off.
While regulation is essential to limit the damage caused by artificial nitrogen, measures like the Nitrite Vulnerable Zones might not go far enough to drastically curtail ammonia emissions. The Government might also consider the introduction of a tax on artificial nitrogen fertiliser to disincentivise the purchase and use of the product by farmers and create the necessary impetus to curb global addiction. By financially disincentivising the use of fertilisers, conventional farmers would have to consider how to build soil fertility through natural methods.
The use of forage legumes in rotations increase the soil’s natural nitrogen levels and help to reduce the use of artificial fertilisers, significantly lessening the amount of reactive nitrogen in the atmosphere. Encouraging farmers to adopt the practice of cover-cropping with nitrogen-fixing varieties will help to reduce the over-reliance on artificial fertilisers and the Government should use the new Environmental Land Management (ELM) scheme, as outlined in the Agriculture Bill, to financially incentivise the inclusion of nitrogen-fixing legumes in productive grasslands and as cover-crops. The Sustainable Food Trust has advocated that by using the ELM scheme to incentivise the use of legumes in rotation, Defra could help farmers to deliver the multiple public goods including soil health, water and air quality and biodiversity.
To achieve the systemic shift towards more sustainable farming methods and reduce artificial nitrogen usage, society needs to unlock the barriers to change and, through the new Agriculture Bill framework, the Government can create the economic conditions where farmers are financially supported for adopting agroecological practices, which can then emerge as the most profitable and economically-viable way of producing food.
Join us for our session, ‘Nitrogen Pollution and How to Reduce It‘ on 4th January at 3pm in the Long Room. The session is organised by the Sustainable Food Trust and chaired by Patrick Holden, with speakers including Jenny Hawley (Senior Policy Officer at Plantlife), Helen Browning (Chief Executive of the Soil Association), Robert Craig (Cumbrian Dairy Farmer and Nuffield Scholar), Honor Eldridge (Head of Policy, Sustainable Food Trust) and Dinah Hillier (Catchment Control Manager at Thames Water).
Photograph: Bill Meier
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