About Soil
What Is Soil?
Soil is fascinating! It’s shaped from the complex geology that existed in a landscape by the forces of biology and weather, forming a thin layer at the earth’s surface that we depend on for life
Why is soil important?
Soil is the corner stone of life in our world; just one teaspoon of healthy soil has more life in it than there are human beings on Earth. It provides a range of incredibly important ecosystem services, particularly for people as 95% of our food is grown in the soil.
Soil holds the key to our planet’s past and future and is the answer to our food, water and energy security, mitigating and adapting to climate change, the safeguarding of biodiversity, and the protection of human health. Many of the UN Sustainable Development Goals cannot be achieved without healthy soils, sustainable land use and strong policy
What Actually is Soil?
To the naked eye, soil may look uniform. Dig a bit deeper and it comes in many different colours, textures and structures. At a microscopic level, soils consist of complex structures of soil grains aggregated together to create a complex network of pores. The particles are chemically active, slowly but continually changing in composition and shape, and binding nutrients essential for plants and toxins from the environment. The spaces between these grains are filled with constantly changing mixtures of air and water, and are inhabited by huge numbers of microscopic organisms.
What is soil made of?
Soil is a mix of mineral matter (weathered rock), air, water and organic matter. The balance of these components is important, especially for organic matter. It may be a small component of soil, but organic matter gives soil life, binds particles together and helps trap water. Of course, there is a lot of variation in soils which depends on where and when they formed, and how they have been managed. Minerals break down into different sizes over time, giving soil diverse textures:
- Sandy soils
- Silty soils
- Clayey soils
- Loam soils
The soil may also be almost entirely organic matter, forming Peaty soils. The minerals also have a big impact, such as Chalky soils.
What is the role of soil in mitigating climate change
Soil has a vital role in the fight against climate change, as soils store large amounts of carbon and have the capacity to trap more. There is more carbon in soil than in vegetation and the atmosphere combined. It is estimated that there are 1,500 gigatonnes of carbon in the world’s soil; three times more than in all vegetation and forests. Deforestation, global warming and poor agricultural practices can lead to the release of soil carbon into the atmosphere, and in turn speeds up the climate warming process.
To find out more about the importance of carbon in soils, how it behaves, and how it might be increased to help address the climate crisis, read our Science Note.
Are Soils under threat?
Desertification, loss of biodiversity, soil sealing, and soil contamination; these are just a few of the big threats that soils face. According to a government summary of the state of the soil environment from 2023, 4 million hectares of soil in the UK were at risk of compaction, over 2 million hectares were at risk of erosion, and arable soils had lost 40-60% of their organic carbon. The summary also detailed that microplastics in soil had become widespread, potentially causing long-term issues that we currently do not know the impact of and documented that over 300,000 hectares of soil had become contaminated. With all this in mind, we think it is fair to say that soils are under threat.
Are we Making Soils Better?
Despite all the issues and threats to soil mentioned previously, there are active efforts to improve the condition of our soils. The work of our Society’s members in particular, are an excellent showcase of the work to further knowledge of and preserve soils. Our members are educators, working to replenish the dwindling number of expert soil scientists. High quality science is important to find cutting edge solutions to improve soils. The BSSS journals, the European Journal of Soil Science and Soil Use and Management, publish the latest research findings that tackle many of the challenges listed above. We bring this research to the public with our accessible podcast ‘Soil Matters’, and to broader audiences like school children via our soil loan box programme.
There are several things that we can all do to help foster healthy soils. These include removing patio slabs from your green spaces, planting cover crops, and not using peat-based compost. To learn how to stay #Grounded click here.
There are bold plans from governments across the UK to expand the area of soils under sustainable soil management by 2030. The evidence being gathered by our members, and their work supporting industries reliant on soil will help make this happen. It needs investment so that soil can continue to support so much of humanity and the environment.
