5 December 2019

Soil degradation and why it matters

On UN World Soil Day we talked to Dr Anna Krzywoszynska about soil degradation and why it matters.

Hands holding soil

Can you explain what Soil Erosion is?

Soil erosion is a form of soil degradation where part of the soil is carried away by water or wind. Through erosion the soil’s capacity to function is weakened or even lost. While we have spectacular examples of soil erosion in the UK, most of the erosion that happens on the British Isles is quite slow and distributed. As soil loss is very slow we often don’t notice or see it happening and therefore it is not taken sufficiently seriously.

Heavy rainfall gives us a clear view of soil erosion when the ocean surrounding the British Isles turns brown from all the soil lost from fields. You can see this visibly on the satellite image in George Monbiot’s article.

Why is it happening? What is causing soil erosion?

In the UK our soils are losing organic matter. Organic matter in the soil makes soil aggregates - the main soil particle if you like - more resilient to weathering. Historically soils in the UK have been deforested and today they are often intensively farmed. Due to modern farming sufficient organic matter often isn’t returned to the soils (through crop residues, manures, or compost). When organic matter is not replenished it then diminishes harvest after harvest.

It’s really important to understand that soil needs our care and protection. Without careful practices and attention to organic matter, soil can be degraded and lost very quickly. One thing we could do to protect British soils from erosion is to develop mechanisms which give farmers easy and effective ways to increase organic matter content. For example by developing better links between urban food waste and organic waste streams and farmland.

Why does it matter? It’s only dirt!

Without soil our planet would just be a lifeless heap of rocks.

Healthy soil is the vital base for all life – human, animal, plant, microbial. We know that without healthy soil, most food production becomes all but impossible; and we recognise that some of our food production systems are leading to unprecedented levels of soil degradation.

Soil is important not just for food production, but for everything we need to live on the surface of this planet, including fresh water and clean air. Lately soil’s role in capturing carbon from the atmosphere has been attracting attention. By changing land use by for example turning arable fields into pastures or forests, we can capture carbon in the soil. In the current climate crisis we need as much help as we can get to prevent more carbon from being released from soils, which means protecting current forests and pastures, and supporting farming methods which are less carbon intensive.

A large part of our research involves working with farmers and landowners throughout the country. There are strong emerging farmer groups in the UK who are changing what it means to be a farmer to incorporate sustainable land management practices.

Dr Anna Krzywoszynska

Institute for Sustainable Food

What is happening at the Institute for Sustainable Food in relation to soil erosion?

At the Institute we are taking a multidisciplinary approach to improving soil health.

The research by Jonathan Leake, professor of plant-soil interactions at the University of Sheffield, found that traditional grass-clover leys and species-rich herbal leys have rapid restorative effects on soil quality and on subsequent crop yields.

Professor Leake’s research has shown that if we allow soils to exist in herbal leys for five years the soils will regenerate to a great extent. However, it is a big ask to landowners to put their fields ‘to rest’ and take them out of production. Implementing this will require concerted action by many actors in the food system.

At the Institute we are also investigating the potential of vertical hydroponic growing, which could help ease pressure on our land and allow the farms and soils to have this offset time to regenerate.

Professor Hamish Cunningham, research professor in computer science, has developed a system which can grow food in water which is fertilized by fish. The system is controlled by a device called the UnPhone, developed in conjunction with Sheffield manufacturer Pimoroni. This technology means you can ensure that the key water parameters such as pH and water temperature stay in the correct ranges and you can match the conditions for growing with what you want to grow.

There are a number of researchers working on these growing systems, and we have fantastic projects locally in Tinsley and as far afield as Oman and Jordan.

A large part of our research involves working with farmers and landowners throughout the country. There are strong emerging farmer groups in the UK who are changing what it means to be a farmer to incorporate sustainable land management practices. Farmers see the problems first hand, often across generations as our soils slowly degrade in the UK. They know how important soil health is and we build links with these communities to give scientific support for their learning. Having support from our researchers gives legitimacy for new farming practices so farmers can confidently share their new ways of working with their peers.

To achieve systemic change needed to protect our soil health, and we believe supporting farmer peer to peer learning is vital to addressing this challenge.

Tractor ploughing field

If we continue as we are how bad will things get?

The way that we choose to use our soils will determine the future we live in.

Some form of food production will always be possible. Today we are living in a world where soil degradation is accepted. Soil degradation exacerbates the extinction of whole species and destruction of ecosystems and societies which depend on those ecosystems. Continuing down this path may lead us to us living in fortress societies where those with healthy soils or with access to capital-intensive forms of food production have food and strive to protect from others it at any cost.

By conserving soils as the basis of well-being for both humans and nature, we will choose a future which creates social and ecological justice. When soils are healthy, human conflict and ecosystem damage also diminish. Soils are the foundation of a good social and ecological future. Our work at the Institute to influence policy change in this area is of paramount importance for everyone.

As individuals what one thing can we do to prevent soil erosion?

If you have any land, the best thing you can do is plant a tree. Trees help to capture carbon from the atmosphere, they provide shelter for wildlife and help to prevent flooding. They help to enrich our soils.

If planting a tree isn’t possible then grow a messy garden. Rip up your paving and grow plants, flowers, wildflowers and grasses. Compost at home and add organic matter to your soil. Never leave the soil in your garden bare. Messy is beautiful!

Get out in nature and look around. Everything you can see growing is five to ten times bigger underground. You are walking on a living, breathing entity that we need to protect.

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