It’s so easy to overlook the importance of soil. After all, it’s always been there, under our feet. We build houses on it - creating streets and communities. It hosts forests, farmland, pastures, parks and gardens. It’s easy to think of soil as being static… as just dirt. But as we zoom in, we see it is teeming with life. Just one teaspoon of soil can hold more organisms than there are people on earth.
Soil is a complex dance of chemical, mineral and biological processes... and we have a close relationship with soil and its’ health - even though it may not be immediately obvious.
What is soil?
Soil is one of the most diverse ecosystems on our planet. It first started to form around 400 million years ago and is the combination of weathered rock, broken down and dissolved by a combination of weather, plants, lichen and microbes. We’re looking at a span of around 3000 years for fertile soil to be created from scratch. Then to top this up with even just 1cm of new soil takes 200 to 400 years. Soil is definitely not a renewable resource.
Soil is a living organism. It’s a hotbed of biological and chemical reactions created through the interaction of plants, animals and microbes that live in the soil, along with those that live on it. It is these processes that underpin life on our planet as we know it.
Why is soil important?
95% of our food relies on soil for its’ production. Soil anchors plants and feeds them so they can grow. Farm animals are fed on plants and in turn, plants and animals are our main sources of food.
Soil is vital to our ‘food security’, which is rapidly becoming an issue. Business as usual is showing itself to be unsustainable and governments across the globe are starting to grapple with how to make sure their population gets fed. This is not just in far flung places, but here too in the UK. With reports such as the 2021 ‘Independent Assessment of UK Climate Risk’ specifically mentioning issues of food security in its advice to the UK Government.
Combating climate change
Soil is one of our most important weapons against climate change. Soil stores carbon, through a process known as ‘carbon sequestration’. The UK’s soil holds nearly 10 billion tons of carbon. That’s equivalent to the total global emission for the entire planet for a whole year. Globally, soils store more carbon than the atmosphere and all the worlds’ plants and forests combined.
Clean water and flood prevention
Soil actively filters our water and also helps to protect us from flooding.
In the UK, there is around 130 trillion litres of water stored in our soils. That’s more water than in all the UK’s lakes and rivers combined. When soil is healthy, it can store up to one and a half Olympic size swimming pools worth of water per hectare. Poor soil doesn’t hold onto water the same, causing it to run off. This depletes the soil further and exacerbates issues of pollution as nutrients enter watercourses. And of course, water run off only adds to the issues of flooding that we face.
Finding solutions in soil
In recent decades, our relationship with soil has been that of take, take, take – with little regard to the health of the soil that feeds us. According to the Soil Association, we currently lose topsoil between 10 to 40 times faster than it is formed. We are now realising that the answer to many of the serious issues we are currently facing as a society - climate adaption; safe and affordable food; clean water; flooding; pollution – all begin and depend on the health of the soil and our relationship with it.
Nurturing our soil
On our farms, agricultural land and in our gardens, there is the practice of exposing the earth and leaving it bare. When it rains on bare earth, it caused the nutrients to leach out which depletes the soil. It also causes the fertile topsoil to wash off, which can then become silt and pollution in our waterways.
Soil depends on the relationship between microbes and plants to thrive, so the agricultural industry is fast learning the importance of ‘green manure’ and ‘cover crops’ - These are plants that are grown so the soil is not left bare when the food crops are harvested. We can learn from this in our gardens by using green manure (such as Vicia sativa) which keeps the soil in good condition - retaining nutrients and its’ ability to hold moisture. Then incorporating the green manure into the soil when it’s time for it to be cut back nourishes it greatly.
Things you can do in your garden to nurture soil:
· Compost your food waste and add it to your garden – websites like Zero Waste Scotland have great ‘how to’ guides and videos to get you started.
· Take a ‘no dig’ approach to gardening. This protects the life of the soil and helps reduce surface evaporation, which helps the soil retain its’ moisture.
· Smother the soil with planting. Ground cover plants are great for this job. Good candidates are creeping herbs like creeping thyme (Thymus serpyllum) in a sunny spot or sweet woodruff (Galium odoratum) for the shade.
· Use green manure, such as Vicia sativa, in the time gaps between planting to avoid bare earth.
· Mulch with well rotten, biodegradable mulches such as compost, manure or wood chippings to help boost the fertility and structure of the soil.
· Grow a diverse range of plants, including ones that are really beneficial to soil health, such as clover, legumes and trees.
You can also:
· Go organic in your garden
· Support organic farmers by buying their produce.
You don’t need to be a gardener to help look after the soil. There are plenty of simple things we can all do to keep it healthy. We’ve been hearing a lot about microplastics lately, and their impact on the oceans. Laundry is a major source of this pollution, with microfibres being washed from our clothes into the waste water system. It’s estimated that 35% of ocean plastic pollution is attributed to this. But water treatment captures around 98% of the microplastics going through the system. This sludge becomes ‘biosolids’ which is spread onto agricultural land as a fertiliser. So plastic is becoming an issue in polluting our soils too.
Things we can do to avoid microplastics entering the environment:
· Make a move towards clothes made with natural fibres (with no additional chemical processes)
· Wash clothes less and wash with a full load in the machine.
· Use washing machine filters (France is the first country to announce it will insist that all new washing machines have microplastic filters by 2025, I’m sure we will be soon to follow)
· Use plastic free cosmetics – many products contain microplastic beads.
When we understand the issues, we are in a much better position to do something about it. You can help by:
· Raise awareness by sharing what you have learnt about the issues and the things we can do to help.
· Learn more about what you can do by visiting websites like the Soil Association Scotland.
· Support the Soil Association and other likeminded organisations who are campaigning to make our governments take action to protect our soil.
‘Our planet is called ‘Earth’ for good reason. Soil is one of our most important natural resources. It is the planet’s skin, a rich and complex ecosystem that provides the life systems we all need to survive: oxygen, clean water and food. It is no exaggeration to say that civilisations rise and fall according to the health of the soils on which they are built.’ – Soil Association 2021