We need soils but they’re under threat

CIWEM has recently updated its’ soils policy position statement, covering the value, threats, and policies needed to protect and enhance soils. This blog focuses on the threats soils face.

Soil is the foundation of life. Literally. It supports the buildings we live and work in but also provides services that we couldn’t live without. We rely on soils to support wildlife and provide nutrient cycling, carbon sequestration, water filtration and goods such as food, building materials and energy. Meeting the United Nation’s Sustainable Development Goals, the 25 Year Environment Plan commitments and working towards net zero all need soils to be protected and enhanced.

However, our soils are not being meticulously cared for. Despite their huge value to nature and humanity soils are facing, and suffering from, several threats.

• Erosion- We’ve probably all seen brown streams running down country lanes after heavy rainfall in areas of intensive farming, but erosion isn’t limited to these circumstances. It can also be caused by wind and affect areas where soil is sandy or peaty, despite more sustainable farming practices.
• Decline in organic matter- soil health depends on a range of factors including organic matter which is closely linked to biodiversity. According to the Committee on Climate Change “Nearly 4% of UK greenhouse gas emissions in 2013 were due to losses of soil carbon – a total of 22.5 million tonnes CO₂ equivalent”.
• Local and diffuse contamination- There are loads of potential contamination sources and different levels of contamination. Acute contamination can be a particular issue in industrial areas, for example following spills, whereas diffuse contamination can be widespread resulting, for example, from atmospheric deposition.
• Covering and sealing- with our ever-expanding population and changes in lifestyle, increases in buildings and infrastructure are covering and sealing soils
• Compaction- soils squashed under weight can’t perform as well. Water runs off compacted soils instead of being stored and filtered.
• Decline in biodiversity- Declining soil health reduces its ability to support biodiversity, which starts a downward spiral. Biodiversity is valuable in its own right but can also improve soil health. For example, earthworms help improve soil structure, decompose organic matter and support bacteria and fungi.
• Salinisation- being an island, parts of Britain are at risk from sea water flooding. With climate change and predicted sea level rise this risk is not only here to stay but likely to worsen. Saltwater can significantly reduce the fertility of land for cropping which can take some years to fully recover from. Flooding is not the only route to salinisation, intrusion of sea water in coastal aquifers is another route.
• Flooding and landslides- these can result in erosion, compaction and sealing which we’ve established above are bad news for soils.

We can’t eliminate all the risks soils face, but we can raise awareness and improve the policies that guide farmers, developers and others to manage them and reduce the impact on soils.

Our latest policy position statement sets out 14 recommendations to address the threats soils are facing. Access the summary and the full statement here.

Sarah Anderton

30/07/2019