Act: Inspiration

Improving Air Quality with Clover

September 20, 2018

In August, the Sustainable Food Trust submitted a response to the Government’s new Clean Air Strategy consultation. Air pollution is a huge issue in the UK with more than 40 towns and cities at, or exceeding, air pollution limits set by the World Health Organization. This has significant public health impacts, since an estimated 40,000 premature deaths in the UK are attributed to air pollution.

It has long been known that poor air quality damages public health, but recent research would suggest that the impact has been vastly underestimated. A recent study from Queen Mary University of London reported that air pollution can actually change the structure of the heart, increasing the left and right ventricles.

Attention has focused on urban areas and vehicle emissions. As a result of government action on car exhausts and industry, UK emissions of nitrogen oxides have fallen by approximately 70% in the last two decades. However, the impact of farming on air quality has been largely overlooked. In the UK, farming accounts for approximately 80% of all ammonia emissions, primarily from artificial nitrogen-based fertilisers. When ammonia drifts over industrial regions, it combines with other pollutants to form solid microscopic particles that can stick in fine lung tissue, contributing to cardiovascular and respiratory disease.

While overdue, we welcomed the Government’s new Clean Air Strategy. It is a positive first step, but more will need to be done if we want to reverse the environmental and public health damage caused by decades of bad practice. Greater action to address the root causes of air pollution from the agricultural sector is needed. To face the growing environmental crisis caused by nitrogen pollution, that is already exceeding Planetary Boundaries, there needs to be a fundamental shift in the way that we produce food.

Globalised industrial agriculture requires high inputs of artificial nitrogen fertiliser, which causes irrevocable damage to the planet. Global artificial nitrogen-based fertiliser use is expected to rise to approximately 120 million tonnes in 2018. While nitrogen fertiliser increases crop yields by artificially promoting fertility, it can damage long-term soil health. The over-cultivation of arable soils in the post-war period has led to a substantial loss of soil carbon and has damaged soil structure. Farmers increasingly rely on nitrogen-based fertilisers to artificially build fertility in the soil, which, in turn, causes a further decline in soil biological and microbiological life.

As a result of the globalization of the industrial farming system, soil degradation is a problem worldwide with one third of the planet’s land already severely degraded, and fertile soil is being lost at the rate of 24 billion tonnes a year. In addition to being less fertile, degraded soil is unable to hold water effectively. When it rains, the water simply runs off the land, increasing the risk of flooding. However, it also means that the artificial fertilisers are washed into waterways and pollute our river systems.

Soil degradation needs to be urgently addressed, and we need to shift towards more sustainable farming methods that naturally build soil fertility. In 2017, Secretary of State Michael Gove committed to improving soil health in the UK. However, if the Government truly wants to deliver on that promise, there needs to be a dramatic reduction of chemical fertiliser use.

In the past, the UK Government has relied on identifying and restricting practices in nitrogen vulnerable zones (NVZs) to tackle pollution from fertiliser run-off. NVZs are areas that the UK Environment Agency has identified as at risk of nitrate draining into waters that could become polluted. Given the scale of the problem today, we recommend that the Government extend NVZ to cover all of the UK.

However, for NVZs to be effective, significant improvements are needed. It is almost impossible to monitor individual farm nitrogen use accurately (and resulting emissions). There is enormous potential for farmers to use more fertilisers than permitted. An academic review of NVZs in 2009 concluded the ineffectiveness of NVZs and suggested that nitrate reduction strategies need to be rethought. We’d suggest that conclusion is still valid today.

In addition to reforming NVZs, the Government should use agricultural support post-Brexit to better protect our environment for future generations. The Agriculture Bill was introduced to Parliament this week and emphasises (amongst other essential public goods) the need to protect our air and waterways from pollution. To reduce levels of reactive nitrogen in the UK, Government should use ‘public good’ funding mechanisms identified in the legislation to encourage a wider shift towards agroecological techniques. For example, supporting crop rotations using forage legumes – such as clover – that increase the soil’s natural nitrogen levels, without relying on expensive agrichemicals. This would reduce dependency on artificial nitrogen fertilisers and improve water and air quality.

It is widely recognised that using cover crops between cash crops improves soil health by building soil carbon levels and reducing run-off.  Similarly, applying livestock manures to farmland increases soil carbon levels. With higher carbon levels, the soil’s water-holding capacity increases while simultaneously reducing the need for artificial fertilisers by supporting natural fertility.

This new vision of a future for farming that is environmentally sustainable should be placed at the heart of the Government’s post-Brexit agriculture policy. If Government takes the necessary steps to adopt a new sustainable system of food production that prioritises local small-scale farming, we can begin to ensure a healthy and thriving future for the next generation.

Photo: Chafer Machinery 

Honor May Eldridge

Honor is Head of Policy for the Sustainable Food Trust. Her areas of focus include global development agriculture, immigration in the farming sector, trade policy and agri-tech innovation. She has written briefings on the potential of a transatlantic trade deal, on the unintended consequences of crop insurance programmes, and on soil carbon sequestration. Previously, Honor worked at the Soil Association and was the Legislative and Government Affairs Coordinator in Washington D.C. for the Center For Food Safety.

Tags: air pollution, nitrogen fertilizer