Soil Deserves Our Attention
By Isaiah Ritzmann
Published in June 2021
To save our soils is to save ourselves. We all know that in order to live we need to eat, and in order to eat we need good soil. But soil means much more than good food. Soil is also essential if we want clean water, a stable climate, and physical and emotional health. Soil is a critical part of our wider ecological community, living in reciprocal relationship with humanity and the rest of nature. In our first article of this series we explored the critical dimensions to good soil – soil organic matter, soil structure, and microbiology. In this article we will explore the ways soil relates to the rest of nature, and in turn to us as human beings. We will see how conserving and building good soil can have a multiplier effect. Healthier soil means healthier waters, healthier bodies, and a healthier climate as well.
Soil – Threatened at an Unprecedented Rate
But before we explore these great gifts of soil it is important to understand how worldwide soil is being threatened at an unprecedented rate. Levels of organic matter are dwindling, microbiology declining, and erosion continues at alarming rates. Topsoil, the top 15-30cm of the soil, is where much of organic matter and microbiology – and consequently, fertility – reside. Half of the topsoil on the planet has been lost in the last 150 years. Every year approximately 24 billion tonnes more of it is lost due to erosion – that’s over 3 tonnes for every person on earth, every year. Furthermore our population is growing. According to some this will lead to a situation that by 2050 we will be trying to feed twice as many people, with half as much topsoil.
While these threats are real, the situation is not hopeless. Our World in Data critiques the frequent stated statistic that, due to soil erosion, the world has only sixty harvests left. “Sixty harvests” is true only as an average. As an average “Sixty Harvests” greatly distorts the differences in average soil lifespans. It is true that about 16% of soils have a lifespan of less than a hundred years – but many have lifespans much longer. Some well-cared for soils are even thickening, in a process of soil regeneration. In some ways Canada bears out this optimism. Due to major changes in farm practice through the 1990s and early 2000s, by 2011 the majority of farmland (74%) in Canada was considered to be at very low risk from soil erosion. The work is by no means done, and other risks remain – both at home, and abroad. Nevertheless opportunities do exist to conserve and build soil health.
Soil – Conserving and Building its Health
These opportunities are critical as healthy soils are an ally in our fight against climate change. Worldwide, more carbon is stored in soil than in plants, animals, and the atmosphere combined. As plants grow, they photosynthesize. Through photosynthesis they take carbon out of the air (in the form of C02) and send it down to their roots, where in part it is fed to microorganisms. It’s estimated that worldwide soils could help store (sequester) 3 gigatonnes of carbon a year (compared to about 36gt emitted each year). This is especially true in degraded soils which have more capacity to store more carbon through regenerative practices. Before they were used agriculturally, many of the soils of the world once had a carbon content of up to 20 percent – today their content is estimated to be between 0.5 to 5 percent. Thus the capacity for sequestration, while not a panacea, is significant. For example, soil scientist Rattan Lal estimates that soils in the United States could store more than 300 million tonnes of carbon a year, enough to offset the emissions from all vehicles in the United States.
Soil – Drenched in Chemical Pollution
How we work with soil also affects our waters – for better or worse. When managed poorly, soil can often contribute to water pollution as nutrients meant for plants leach out or are lost due to erosion. By some estimates, as much as 50 pounds of synthetic nitrogen of the over 200 applied to the typical acre of corn will enter the surrounding environment. So much phosphorus and nitrogen (key fertilizers) end up in our water ways that they cause significant problems. These fertilizers start a chain reaction that ends up with massive dead zones – oxygen deprived areas absent of wildlife. Due to run-off from the Mississippi watershed, a giant deadzone appears each year in the gulf of Mexico. There are times in the last decade the dead zone has been the size of Massachuesetts.
The same problem with water pollution affects the Great Lakes. The dead-zone in Lake Erie each summer can be 10,000 km2, and an Algae bloom in 2014 shut-down the water supplies for over 400,000 people in and around Toledo, Ohio for over three days. Elsewhere across the continent water pollution costs municipalities thousands of dollars annually. Des Moines, Iowa – for example – spends $300,000 every year to clean waters of nitrate pollution from surrounding farms.
Soil – Properly Cared For
While these threats to our waters are real, the situation is not hopeless. In fact, when cared for, soil can help make our waters cleaner and healthier. When soils have good structure then they can actually clean the water of toxins and contaminants as water moves through the soil. Organic particles, fungi, bacteria, and plant roots work together to remove minerals, nutrients, and pollutants from the water before releasing purified water into nearby streams. To illustrate just how powerful an ally soil can be for our fresh water needs, consider the example of New York City. Each day millions of the city’s inhabitants use more than a billion gallons of water. Most of this water comes from over two hundred km upstate, and almost none of this passes through water treatment plants. A few decades ago officials noticed the quality of the city’s water was declining – a fact they attributed to intensive suburban development upstate. Original plans were to build a water treatment plant at an initial cost of over $10 billion dollars (not counting future staffing and maintenance costs). An alternative was proposed – instead of building the plant, New York City should purchase the development rights to the myriad of farms upstream. By preserving these farms as farms, with their forests, fields, and pastures, the city would be preserving these soils, with their water-cleaning powers. The city went ahead with the alternative proposal, at a tenth of the cost, but with the same benefits. In doing so it lived a truth: if we save our soils, we save our water.
Soil – Critical for Human Health
As if the climate and water work of soil wasn’t enough, soil also is critical for human health. First, and most obviously, we need to eat. It is from the soil, more specifically the top 15-30cm of it, that we (ultimately) derive all our food. Without food we can’t be alive, and without being alive, we can’t be healthy. Beyond such truisms, it’s important to see the connections between healthy soil and good quality, highly nutritious food. In the past fifty years nutrients in crops have declined significantly. One survey reports that zinc, magnesium, and iron levels in vegetables have fallen by an average of 50%. While the reasons for this are not singular or certain, scientists believe a significant cause has been the decline in soil microbiology, both in sheer mass and in healthy diversity. While it remains in large part a mystery, the dependence of human health on soil microbiology is becoming clearer and clearer. Studies have shown that people who are in regular contact with soil are more resistant to allergies and asthma, whereas experiments with mice show contact with soil biology strengthens their immune systems against parasites, bacteria, and viruses. With this in mind, perhaps we can imagine that lockdowns helped prevent the spread of COVID-19 by sending more and more people into their backyard gardens? Maybe that’s fanciful. Maybe not.
Soil – Critical for Human Mental Health
Yet healthy soil isn’t only good for physical health. It’s also good for mental health as well. Although it is complex and mysterious there seems to be strong connections between healthy soil biology, our own gut biologies, and our mental and emotional well-being. As we work with soil, or even just eat food coming from healthy soil, we ingest some of these soil microbes which become part of the flora and fauna in our digestive system. Some bacteria in the soil – especially Mycobacterium Vaccae – has been proven to help produce serotonin, a neurochemical that can make you happier and less stressed. Furthermore a lack of serotonin has been linked to all sorts of mental health challenges, ranging from anxiety and depression, to obsessive-compulsive and bipolar disorders. In other words exposure to soil microbiology can work somewhat like an antidepressant. So next time you’re feeling low, why not go and garden for a bit? Of course no one is saying soil is the panacea – for mental health or physical health. Nevertheless it is becoming clearer and clearer that good soil strengthens our bodies and our souls.
Soil – A Collective Imperative to Conserve and Enhance it
With such diversity of benefits – food and health, a stable climate and clean waters – how else can we respond but by cherishing and honouring the soil? Furthermore how do we respond to the grave threats against soil health globally, especially the loss of topsoil? As has been hinted at in this article already there exist many ways, as individuals and as societies, to care for and regenerate the soil. Our collective task is to choose methods that conserve the soil rather than damage it. In the last article of this series, to be published in the September Issue of Good Work News, we explore these methods. What does it mean in our backyards and our neighbourhoods to care for the soil? At a larger scale what does it mean for farmers to conserve the soil, and in what ways as citizens and consumers can we support them in this work? This is no small task. After all half of the topsoil on the planet has been lost in the past 150 years, with billions of tonnes being eroded yearly. Yet as we will see, although the threats are real the situation is not hopeless. We can still save ourselves by saving our soil.
