What Is Soil Health? Why We Shouldn’t Treat It Like Dirt
Turns out there is a gold mine right below our feet. What makes soil healthy and why does it matter? Romally Coverdale investigates.
Soil determines the health of everything on this planet, and so is hugely important in both our lives now and the future.
In this article, we will break down how and why soil is important, and what you can do to help keep our soil healthy.
What is healthy soil?
Firstly, there are multiple layers of soil from the topsoil at the surface all the way to bedrock.
Due to the focus of this article, I will mainly focus on the topsoil.
There are 18 elements that are considered crucial to for our plants to grow, most of which rely on healthy soils.
There are multiple factors affecting soil health, the main ones are:
- Organic matter content
- Correct pH (ideally 6.2-6.5pH)
- Water infiltration and retention
What is soil?
Soil is a mixture of organic matter that comprises the upper layer of earth.
Without this organic matter, soil turns into sand. Soil also has multiple varieties and compositions.
Did you know soil is only called soil when a certain percentage of organic matter is present?
While in rainforests the organic matter is over 70%, in agriculture the minimum is 3%.
The rest of the soil is composed of minerals, living organisms, air and water.
Yet due to industrialised agriculture, the majority of soil does not meet this requirement.
For example, 62% of soil in India is made up of 0.5% organic material or under.
75-85% of soil in major EU nations has less than 2% organic content
Almost 90% of soil’s biodiversity is in the 12 inches of topsoil - the area that is ploughed and destroyed with heavy machinery.
Alarmingly, by 2050, 90% of the Earth’s topsoil could be degraded with 52% of the world’s soil already degraded.
What does soil need to be healthy?
Other than organic matter, soil needs phosphorus, which is contained in its own natural cycle, is essential for life and has been used as fertiliser for millennia.
While industrial fertiliser was used to help combat demand for food, the over use of phosphorus in industrial farming has led to new vulnerabilities and threatens to destabilise the world’s food system.
This is due to the environmental repercussions of using phosphorus, where it leaks into the environment causing a variety of damaging issues.
It is estimated that phosphorus pollution affects nearly 40% of Earth’s land areas
Without enough phosphorus, the plants are unable to grow healthily, applying all their energy to grow roots in order to seek the minerals needed.
Phosphorus helps plants resist disease and increases the quality of the plant, while nitrogen enables photosynthesis, growth and increases yield.
Why does soil matter?
Soil is the foundation for 87% of the world’s biodiversity.
It helps grow plants, which feed animals and people, meaning soil quality and soil health directly responsible for entire ecosystems.
Consequently, if the soil is unhealthy, entire ecosystems are affected.
We are already seeing the consequences, with over half of the world’s soil already degraded.
This is a pressing issue, as within 50 years we will not have enough arable topsoil to feed everyone, and the food that will be produced will be nutritionally degraded due to the loss of important minerals.
By 2050, 90% of the Earth’s soil could be degraded
When soil is not healthy it affects:
- Quantity and quality of produce
- Entire ecosystems
- Whether land is arable
- Carbon emission levels
- Resistance against flooding/water retention
How soil is a carbon sink
Over the past 150 years, the amount of carbon in the atmosphere has increased by 30%, and it is no secret that the global climate is changing.
Soil health and climate change are very much interlinked.
Soil is just as needed as other important CO2 absorbers, playing a crucial role in the carbon cycle by soaking up dead plant matter.
The CO2 absorbed by plants is then taken into the ground once they die, the same with animals and all organic matter.
Carbon sequestration is the long-term storage of carbon in oceans, soils, vegetation and geological formation, showing how vital soil is in the carbon cycle.
It is estimated that soils have lost 50 to 70% of the carbon they once held
Soil loses carbon and organic matter through:
- over tilling
Soil is often thought of as a finite source - but it doesn’t have to be.
There are many ways in which we can maintain and improve soil health, as explored in our article on permaculture
There are other ways too.
In fact studies show that if one third of the world’s soil was put under shade, climate change could be reversed.
Likewise, increasing soil’s carbon content can halt the rise of CO2 in the atmosphere and begin absorbing it back.
If treated right, global croplands have the potential to store an additional 1.85 gigatons of carbon each year - neutralising the global transport emissions.
How is soil degraded?
The organic content of soil within rainforests is 70%, over 10 times the amount used in agriculture.
This is because the soil is continually covered and protected from the multiple ways it can be eroded.
The dense biomass and plant life keeps the soil healthy and fed, protected from intense rainfall letting it trickle over time and from harsh wind.
On ground level, the decomposing shrubs also feed and protect the soil.
Strong ecosystems and a dense biomass makes the soil a greater defence against natural disaster (i.e. flooding) and is more nutrient rich.
Good soil also makes for greater biodiversity, yet due to poor land management we have already lost 80% insect biomass over the past 25-30 years.
Earth loses roughly 23 billion tons of fertile soil every year
Deforestation results in this 70% of organic matter to be lost, along with other indicators of soil health like minerals which are lost by leaching.
Processes, like industrial tilling, degrades soil, accelerates surface runoff, disrupts water cycles, and can even lead to desertification and salinisation.
Desertification has been described as “the greatest environmental challenge of our time"
Heavy machinery used in industrial farming compacts the soil, killing the organisms, underground habitats and availability of nutrients.
Agriculture and deforestation are not the only big players in soil degradation, increasing urbanisation causes the death of microorganisms too.
Without good soil and natural landscapes, urbanised areas paved with concrete and tarmac makes these areas more susceptible to flooding and other natural disasters.
We recommend reading about Urban Gardening and its benefits if this concerns you.
Despite the growing demand for food in order to feed a growing population, it is expected that a significant amount of agricultural land is to be abandoned in the next 20-30 years in Europe. See the areas of Europe affected by erosion.
Nature would not be able to recover on its own. To learn more about helping nature recover read our Rewilding book recommendations.
Why we need good soil to feed ourselves
At the current rate of degradation, food production could fall by 30% in 30 years.
However, improving soil health raises crop production by 20-40% as well as making the produce more nutrient dense.
The need for change is apparent. There has been a 60% protein drop in Indian vegetables and 87% drop in mineral nutrients in US vegetables.
Degraded soil means degraded produce. At the current rate of degradation, food production could fall by 30% in 30 years
Soil is crucial in feeding ourselves and the planet, as well as creating a greater availability of water due its ability to retain water.
By looking after soil, it can eliminate water scarcity for 600 million people as improving organic matter will increase water reserves by 37 trillion litres.
The soil’s structure affects plant growth as healthy soil has good drainage and less watering is needed, provides better anchorage and stability, greater aeration, and more consistent temperature.
Of course, healthy soil also provides the essential nutrients for plant growth too, which is needed throughout the food chain.
It is estimated that we only have 45-60 years of soil left.
This is why organic methods and sustainable farming build healthy soil; it maintains oil structure and the organic matter.
By using no chemical fertilisers and pesticides, it maintains the soil's natural pH and organic content. Instead we should be looking towards, regenerative agriculture focuses on restoring and maintaining soil health through a variety of means including cell grazing, mulching and no tilling.
How to increase soil health and why compost is great
Organic fertiliser (like compost) improves the soil structure by increasing the biomass and microorganisms and is one of the main solutions to degrading soil.
By mixing richer soil with degrading soil improves the overall organic content, providing the degrading soil the support it needs to become healthier.
Composting is one of the easiest ways to improve soil health, by decomposing organic materials to ensure a nutrient rich soil.
Compost is the ultimate way to make healthy soil for plants.
Composting also helps the environment, by cutting down on food waste being sent for disposal, preventing harmful gases and reduces the reliance on peat.
Building healthy soil involves a variety of organic matter.
You don't always need a garden either. Check out our guide to Urban Composting: Why It's Time To Get Your Worm On
What can I compost?
There are lots of everyday items that can be composted in your garden or green space. These can be segmented into two categories: ‘greens’ and ‘browns’.
Under ‘greens’, you can find:
In ‘browns’, you can find:
- Egg shells
- Vacuum bag contents
- Wood ash
The green items create the initial heat that is required for the process due to the bacteria, enabling the beginning of decomposition and giving insects food.
This decomposition of organic matter means that phosphorus becomes available.
The aim for a complete compost bin is to maintain an ecosystem of bacteria, insects and fungi - which is why the brown materials are needed in a 50/50 split.
For more information on composting, read the Wildlife Trust’s guide.
Similarly, for choosing and building the compost heap container itself, the BBC has a great guide.
If compost is made correctly, it can help control diseases in addition to feeding plants nutrients and water.
To increase nitrogen in the soil naturally, compost is essential - and is enhanced by mixing in coffee grounds.
Likewise, planting nitrogen-fixing plants helps maintain nitrogen balance; that is why cover crops like clover are encouraged, or peas and beans.
Rich compost is also a great way to increase phosphorus naturally, alongside using bone meal, seaweed or rocks to provide an additional boost.
Read more. Do more...
Love growing? Don't miss some of pebble's other inspiring content in our Sea Change series, all about Feeding Ourselves.
Learn more from our explainer What is Permaculture?
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