Beneath the surface of 'World Soil Day'
Article by Stuart Ritchie, Educational Gardener at Castlebank Horticultural Centre in Lanark
World Soil Day (WSD) is held annually on 5 December as a means to focus attention on the importance of healthy soil and advocating for the sustainable management of soil resources.
Healthy soils are essential to life on Earth. Without them, we would simply not exist. Apart from what we catch from the world’s oceans, every piece of food you eat is dependent on there being healthy, fertile soil to grow it in. From bananas to beefburgers, these foods are available to you because of nutrient rich soils around the world in which plants grow.
So, what is soil anyway? Often, I hear children and adults alike talk about dirt, mud, soil, ground, muck, compost, and earth. But what are they talking about? Are they all the same? I doubt we could successfully grow nutritious carrots in some ‘Mud’… but we certainly can in good ‘Soil’!
Soils come in many forms. In fact, there are thousands of different soil types found around the globe. Each soil is created by the weathering of a particular rock type, by climate, biological action and huge amounts of time, thousands of years in fact. Each soil has a unique chemistry, biology, and water storage capacity. This means there are soils which are good for growing food crops, whilst others are not. But it’s not all about growing food, soils are vitally important in so many other ways.
Soils are integral to the success of all life on Earth’s land surface, including human civilization. For example, much of Scotland is blanketed by peat soils which have developed over the last 12,000 years, since the retreat of the glaciers at the end of the last ice age. These peat soils store unbelievably vast quantities of rainwater, and without them our towns and cities would be flooded after every Scottish downpour! This is exactly what is increasingly happening in Northern England, in the towns below the Pennine hills, where people have been irresponsibly draining peatlands to create farmland and forestry for several hundred years.
As these same peat soils develop, they draw down enormous amounts of carbon dioxide, the main greenhouse gas which regulates Earth’s climate, storing it as organic carbon for many thousands of years. Elsewhere, in our woodlands, soils are the foundation which support ancient trees and the incredible biodiversity of insects, birds and mammals that are the identity of Scotland’s wild places. Without soils teeming with insects, worms, and other invertebrates, what would the blackbird eat? Nothing is the answer. But the picture is far more complicated than that.
Soils are alive. It is the biology of trillions of living organisms, from earthworms to downright miniscule bacteria that makes a fertile soil what it is. A soil is not the same as ‘dirt’, which is made up of small particles of all manner of stuff. Soil is also not the same as ‘compost’, which is something made only of well-rotted plant matter. Well-rotted plant matter, however, is a vitally important component of most soils! This is a distinction which is very important to make.
We all ought to have a greater sense of respect for just how important soil is to both the natural world and human civilization. Today is United Nations world soil day. This is an annual event dedicated to raising global awareness of the importance of soils, and to highlight the enormous challenges we face in protecting them.
It takes roughly 500-1000 years for 2-3cm of soil to form. It is a precious resource which we should cherish, since we cannot live without it. However, in the last 150 years, due to our actions, half of Earth’s fertile topsoil has been lost through erosion. Erosion rates from ploughing fields loses soil anywhere from 10 to 100 times faster than soil is formed. Put simply, all over the world we destroy forests and countless other natural ecosystems which stabilise soils.
Without stabilisation, soils just blow or wash away. Our main motivation is to create more and more agricultural land, despite no need for it. As it stands, we waste in the region of 1.3 billion tonnes of food each year. That is about one third of all food produced globally for human consumption. What we waste is sufficient to feed the 800 million or so hungry people in the world, four times over. Yes, we waste enough food to feed an extra 3 billion people, yet we continue to mutilate the natural world at an astonishing rate to create more farmland. Utter madness!
Once land has been deforested for farmland, the techniques used to cultivate the cleared land matter tremendously to the stability of the soil. Some of the common agricultural practices we use to grow much of the world’s food include growing a single seasonal annual crop on large areas of land, large scale mechanical tillage, chemical fertiliser application, and industrial systems reliant on fleets of huge combine harvesters. These practices cause soil compaction and loss of the diverse biological soil communities which make a soil what it is. Many agricultural soils are additionally susceptible to erosion, acidification, and chemical pollution.
The take home message is that how we produce most of our food is unsustainable, it cannot go on this way for much longer. Immense changes to how we manage land are required if we are to continue to successfully feed ourselves over the next hundred years and beyond. If we continue as we are, our children and grandchildren will face tremendous civil unrest including conflict over food resources, malnutrition, or worse. However, if we act collectively now, we can save the world’s soils, cement our food security, and the preserve the ability of the natural world to regenerate from the damage we have caused.
So, what can you do to help protect Earth’s soils, the natural world, and our own food security? Small changes in your own garden help of course, however the biggest impact we can have is by being more selective about the food we choose to buy and the other goods we purchase. Unfortunately, today it can be a hard task to be sure of where our food has come from, and the impacts which have resulted from its production. The picture is very complicated and there is not time to discuss it here.
The clearest piece of advice is to question where your food is coming from. With a little bit of digging, the information is easy to find. Does the chocolate you are eating contain palm oil, produced unsustainably on recently deforested land at tremendous cost to the natural world? Was the chicken you ate last night fed soy protein grown in Brazil, on land which until recently was part of the majestic Amazon forest, whose integrity is vital for the functioning of the global climate system and is the heart of biodiversity of this planet?
These are questions we should all be asking ourselves, to make responsible decisions for ourselves, our planet, and our children. If we do not, Earth’s biodiversity, her life-giving soils and the future of human civilization are all facing a very bleak future.
Find out more about Castlebank Horticultural Centre's Education Programmes via this website.
Disclaimer: All facts and figures referenced in this essay were obtained from peer reviewed scientific literature, they are not the opinion of the writer. For further information, you may refer to the following publicly available resources:
The United Nations
FAO: Food and agriculture organisation of the United States
WWF: World wildlife fund for nature
RESET: Global food waste and its environmental impact