Last reviewed 11 July 2018

Our soils, vital in terms of sustaining us, are under threat. Laura King takes a look at why our land might not be able to feed us in the future and what needs to change.

How often have you considered what is under your feet? Soil is a living, breathing, dynamic system that is as fundamental to our survival as the air we breathe and the water we drink. Civilisations are built on productive soils that provide healthy crops and it still feeds us today. Around 38% of the Earth’s land surface is used for agriculture, and 95% of our food comes from the ground.

Looking around the supermarkets, you would be forgiven for thinking that the world’s farms and fields are as productive and fertile as ever. Sadly, the abundance of varied, healthy-looking produce hides a different truth.

Worldwide, we are losing an estimated 24 billion tonnes of soil a year and it is thought that over a third of our soils are severely degraded. An estimated 970 million tonnes of soil is lost in Europe alone, and in the UK, we are thought to be losing soils at a rate of 2.38 tonnes per hectare each year. Given it can take a thousand years to form just one centimetre of soil, this rate is clearly unsustainable.

We have been disturbing our soils since the advent of agriculture around 10,000 years ago, so what has changed? Why are our soils in so much trouble? Reports such as the United Nation’s Global Land Outlook published last year, and its earlier 2015 report Status of the World's Soil Resources highlight a complex and intricate problem that is as interwoven with politics and economics as it is world hunger and environmental change.

The reports both show that natural and human factors such as climate change and urbanisation all play a part, but one of the biggest causes of land and soil degradation is the very reason we need our soils to remain fertile: agriculture.

The not-so-green revolution

The second half of the 20th century saw the birth of the “green revolution”. In part, driven by the need to feed a bourgeoning global population and a higher demand for food, this method of farming was focused on high yields and lowering costs — and it did both very well. Indeed, it was so successful that, while the world’s population grew by 98% between 1961 and 2000, food production increased by 146%.

The green revolution, with its use of chemical pesticides, herbicides and fertilisers, irrigation and selective growth of high-yield crops, already produces enough food to feed the world. It is a sad fact then that global hunger and food insecurity remain issues today. However, regardless of how much potential our modern mechanisms of farming have for feeding the world, this method of farming cannot continue in its current guise.

There are several reasons. Intensive farming can lead to damaging practices such as overgrazing, taking multiple harvests from the same piece of land, compaction and reliance on chemicals. These methods leave soils exposed and depleted, reducing their ability to function: bare ground increases the risk of erosive forces washing and blowing away valuable nutrients in the top soil; the loss of organic carbon weakens the soil’s structure and reduces its ability to support life, hold water and cycle nutrients; while the overuse of chemicals decimates soil biology as well as polluting watercourses.

All of these actions add up and we are at a tipping point where our need for resources has grossly overstepped our environmental boundaries. We are now at the stage where it’s unlikely that we will be able to continue to produce food much further into the future if the environment isn’t listened to. The Status of the World’s Soil Resources report issued a stark warning: “the majority of the world’s soil resources are in only fair, poor or very poor condition... Further loss of productive soils would severely damage food production and food security, amplify food-price volatility, and potentially plunge millions of people into hunger and poverty”.

The status quo simply cannot continue, and yet food production cannot stop. The world’s population continues to grow and by 2050 food production will need to be 70% higher than the levels seen in 2010. There are many ways in which the world’s governments and policymakers can tackle this situation. We need to see radical shifts in priorities and a reduction in food that is wasted. However, the world’s farmers and food industries also need to start paying much closer to attention to soils under their stewardship.

What about organic?

How organic farming can help the world’s soils and feed the population has been a matter of some debate. It advocates a method of farming that relies on managing the overall ecosystem of the farm rather than using external inputs of chemicals. No manufactured herbicides are allowed, nor are artificial fertilisers. To maintain healthy soils and a viable crop, farmers have to work with nature, using practices such as crop rotation to minimise pests and working organic matter into the soil to restore fertility.

So, is organic farming the answer? Perhaps — but not necessarily.

Organic farming has often been quoted as being less efficient when compared to conventional farming, resulting in lower yields and so requiring more land. This has led some to question its viability given predictions in how much food we need to produce.

The most comprehensive study to date on the data surrounding agricultural yields showed that, on average, organic farming did indeed yield 19.2% less than conventional farming. Crucially, however, this was not the full picture. The study also concluded that the gap is likely to be much smaller as biases in the datasets were skewed towards favourable results for conventional farming. Even more encouragingly for proponents of organic farming, the study showed that certain practices such as growing several crops together on the same field substantially reduced the yield gap, while for some crops such as beans and peas, the gap was negligible. In essence, organic farming has the potential to be just as competitive as its conventional alter ego.

So organic may still have potential. However, there is plenty of evidence to suggest that throughout history degraded soils — with or without the input of chemicals — have a role to play in the collapse of societies as sure as conquest, war and climate change. As with everything, it’s never quite as simple as one thing or another, but it is clear that bad soil stewardship can happen regardless of whether chemicals are used.

Perhaps more importantly than simply focusing on organic, we need to ensure that all methods of farming respect the environment and natural cycles. Organic farming is one way to help promote this, but it’s not the only way.

Cycles and networks

There are many mechanisms to improve degraded soils. One method advocated by many, including the Soil Association in the UK, is to increase its organic matter.

High levels of organic matter is good for food production as it improves the structure of the soil, helping aeration, drainage and root development. It also acts as a good reservoir of nutrients and water providing plants with what they need to grow into healthy, nutritious crops.

However, from flood prevention to carbon storage, we also need our soils to sustain us in more ways than pure calorie intake. In many cases, improving soil function will also improve these other natural processes.

For example, by the Soil Association’s estimations, increasing organic matter in a degraded soil from 1–2% to 20% would increase the water holding capacity by between 40–100 thousand litres per hectare. Taking the lower figure, you’d need just over six hectares (about the size of six rugby fields) to hold enough water to fill an Olympic-sized swimming pool benefiting flood reduction efforts throughout the UK.

It can also help climate change. Soil is a large reservoir of carbon, absorbing it from plants once they die and start to decay. The amounts of carbon the soil can hold is still being debated — as is the impact of agriculture on soil’s ability to hold carbon. However, regardless of the scale of the benefit, soil with a high concentration of organic matter has the capacity to be an overall sink for carbon.

Sickly soils and soil standards

The average person is unlikely to know how to recognise good farming practice in the fields that surround our villages, towns and cities. We rarely know what goes on in the day-to-day life of nearby farmland, let alone where the produce ends up. As an increasingly urbanised people, many of us have lost the connection with the land and with the soils that support us: many of us would not know what a healthy soil looks like.

The Government does set some standards in relation to soil health. For example, the main payment made to farmers, the Basic Payment Scheme, is only paid if certain conditions are met, including some relating to soil. This means farmers must take reasonable measures to provide soil cover, reduce erosion and maintain the structure of the soil by reducing compaction. In addition, the new Farming Rules for Water also require farmers to reduce the erosion of their soil as this is one way in which streams, brooks and rivers can become polluted.

However, if we are losing soil faster than it is being produced, the evidence suggests that there is still a problem. Indeed, in 2014 scientists from the University of Sheffield predicted that there were only 100 harvests left in the soils of the UK’s countryside. So how do we know whether the produce we are buying and eating comes from a healthy soil that both provides us with all the nutrients we need as well as protecting the environment?

Currently, there are three main standards that consumers can look out for: the Soil Association Organic label, the LEAF Marque Standard, and the Red Tractor Assured Food Standard.

Both the LEAF Marque Standard and the Red Tractor Standard include general conditions for environmental protection, including some specific requirements around soil. The most basic of these is the Red Tractor Standard which requires farms to produce a plan that highlights the soil characteristics of fields and potential management problems and solutions. Practices on the farm have to be adjusted to maintain soil structure and control erosion.

The LEAF Marque Standard goes one step further, requiring that soil is referenced in the farm policy and included in the farm environmental plan alongside targets for improvement. A specific soil management plan also needs to be drawn up and the business needs to document how it is working to reduce any issues identified. There can be no visual evidence of damage to soil such as compaction and erosion and the farm needs to consider long-term sustainability in its cropping cycles. Furthermore, there is an expectation that the farm adopts a general principle to conserve and build up soil organic matter.

As would be expected, the Soil Association’s Organic Standard requires the most from farmers. To meet this standard, farms must be managed in a way that develops and protects soil health, soil structure and reduces erosion. For example, it insists on soils being maintained at all times with a protective cover of vegetation and farms also need to put in place certain practices to improve soil health, including using crop rotation and fertility building leys.

No longer a mystery

Modern mechanical farming with its high yields and chemical input rose to the challenge of feeding the world, but its solution ignored the greater role of soils in the environment and in many cases has also failed to eliminate hunger and malnutrition.

Our unsustainable exploitation of the land has to change. Solutions exist, and the loss of soils is avoidable. However, urgent action does need to be taken. Although we may not all farm the land, as consumers we all have a role to play. Understanding where our food comes from is a start, but we also need to start choosing products that are sustainably produced. We cannot afford to ignore the ground beneath our feet any longer.