What do you imagine when you think of the environment? I imagine most people see a bouquet of greens, leaves floating through the wind, a sea of flowers like a shimmering rainbow, washes of limes and sages carpeting the floor. Or many may see the flowing waves of blue that cascade across the planet, cool gradients that give life and protect a myriad of secrets with complex towers of coral or kelp forests. Even the cynic will imagine sharp bursts of crimson associated with the headlines of warming and imminent destruction. These colours swirl around our imagination and not a single one is brown, the colour that we associate with soil.
Similarly, the demands for environmental justice always feature our trees. We see protests against the destruction of the rainforests, people chaining themselves to the “lungs of the world” and vowing to defend them until their very last oxygen-rich breath. There are also a plethora of conferences aiming to raise awareness about the plight of our oceans and the future of our coral reefs, our guilty consciences plagued with the plastic destruction documented in Blue Planet 2. Even our media headlines are constantly filled with a bombardment of images of black skies and flooded fields, desperate to curb our decimation of the atmosphere and land surface. Soil, once again, is forgotten from the social media frenzy. Yet arguably, soil is the basis of all life.
Our conception of soil as a society is bleak. In our imagination, it is the brown, dirty stuff that lives in the garden. It crumbles and hardens in the heat, leading to the death of our beloved flowers and in the rain it sloshes about and makes a mess. Despite its messiness, it acts as a nursery for beautiful flowers and the crops we consume every day that are the foundation of our lives. Whilst as adults we treat soil as dirty and disease-ridden and something to stay well away from, as children many of us were fascinated with the mud and soil in our gardens. We ran outside, rolling around in the grass and the soil and jumping in muddy puddles. In the summer we made magic potions, mixing all of nature’s ingredients to create powerful love spells or evil curses. Not to mention the mud pies we’d bake, and how we picked and prodded the mole hills to admire the wildlife inside. We got our hands dirty. We believed in the magic.
But what if I was to tell you that magic, now forgotten, still exists. Soil is alive, it is teeming with biodiversity from billions of microorganisms to thousands of worms. Even just a teaspoon of soil contains up to 1 billion bacteria, enlivening it with metabolic and chemical reactions, recycling organic matter and squirrelling carbon away for storage. It is brimming with nutrients, each one with endless possibilities for plant growth. Soil hosts the connections between plants, with thousands of miles of mycorrhizal fungi connecting one plant to the next, facilitating a flow of carbon between them as their way of communication.
Soil is far from boring or dull or even always brown; the planet yields a beautiful array of colours from the red soils of China to the blue sediments of the Philippines. It is even an original source of art and culture as it has been used as a pigment to paint with since the stone age, creating the cave art that encapsulates life thousands of years ago and continues to fascinate archeologists today. Soil is the source of our life, it is where our crops grow, where our animals feed originates and we cannot survive without it.
Nevertheless, what if I were to tell you that this source of life is slowly dying with increasing rates of erosion and infertility? Soil, like the trees, like the oceans, like the atmosphere, is under a barrage of anthropogenic destruction. This barrage is armed with indirect and direct weaponry. Increasing deforestation exposes rainforest soil so the rate of erosion increases as floods and rain remove the nutrient-rich topsoil. This has created an erosion rate of 0.117 Mg ha −1 year −1 in 2019 for the Amazon which is catastrophic. Without the nutrients, less vegetation can grow which further increases the exposure of the soil, culminating in a positive feedback loop of soil erosion. Furthermore, the global drying of the Earth’s surface with contemporary climate change results in the increased evaporation of water vapour from the soil, leaving soluble salts behind. 92% of soils between 2000 and 2016 have increased in salinity in this manner. Plants are unable to survive or grow as the salts accumulate, as is demonstrated within deserts like the Sahara in Africa, which are predicted to expand with the rising temperatures.
Furthermore, intensive agricultural practices attack the stability and fertility of the soil it depends on. Tilling of the soil breaks up plant roots and reduces its stable structure, leading to a decrease in water infiltration. The soil therefore is more perceptible to erosion by wind and rain or runoff. Additionally, monocropping and the usage of chemical fertilisers and pesticides depletes the concentrations of certain nutrients whilst increasing the rest to ridiculously high concentrations. This results in leaching, where nutrients are simply washed out of the soil when it rains, but also sterilisation as it depletes organic material and suppresses the natural bacteria which fix nitrogen (create usable forms of nitrogen in the soil from atmospheric nitrogen). Sterilisation increases our reliance on these chemical fertilisers for growth, though over time, they become less effective and continue to damage our soil.
Our soil supports our development, our livelihoods, and our lives. And yet through the mechanisms described above, and many others, we are destroying our soils on a global scale. It is estimated that by 2080 we will have no fertile soil left. This means that this multi-coloured, magical, multifaceted, highly connected, alive and essential system will be broken, and our food systems with it.
But this ending is not inevitable. As a society and as individuals we can help keep this soil alive. We can always do our part in helping to mitigate climate change and deforestation: turning off our lights, boycotting destructive companies and products as well as demanding change from our governments. We can demand better policies for soil management and monitoring, so as to increase our knowledge and ensure early intervention. We can demand that governments provide better legislation and policing to ensure increased grassland coverage (to improve stability) and regular crop rotation (to reduce nutrient depletion and bare soils). Our farmers can move to researching and implementing soil-friendly techniques to reduce harm. This can include anything from switching to using animal/plant natural fertilisers, reducing compaction on the soils through reducing heavy machinery use and ensuring the surface of the Earth is continually covered so as to reduce wind and rain erosion. All is not lost.
Today soils are alive, but they are suffering and they will continue to suffer and become infertile if substantial action is not taken. Our future and our soils do not have to be bleak. Save our planet, save our soils.