Measuring and valuing: Soil

  • 14.06.2023
  • article
  • Global Farm Metric
  • Measuring Sustainability
  • Soil Health
  • Victoria Halliday

How can measuring sustainability help us to understand and value the produce and services that farmers deliver? In this series, we explore the role of metrics in transitioning to a more sustainable food and farming system, and we meet some of the people who are leading the way. Here, Sustainable Food Trust (SFT) Communications Manager, Victoria Halliday, takes a closer look at soil health and goes to meet mutton producer, Matt Chatfield, on his farm in west Devon.

Regenerative, organic, nature-positive – whatever your definition of sustainable farming, they all have their roots in the same thing: healthy soil. Blanketing the Earth in a layer that is about 13 cm to 25 cm deep, soil serves as the dynamic interface between the dead world of geology and the bustling life of the planet’s surface. It provides the means through which the Earth is able to continually regenerate, turning decomposing matter into new life via the action of microorganisms, which, in just three tablespoons of soil, outnumber the world’s human population.

Reflecting on this miraculous process of renewal, American poet, Walt Whitman, expressed awe, bordering on horror, when he wrote: 

“What chemistry!

That the winds are really not infectious […]

That when I recline on the grass I do not catch any disease,

Though probably every spear of grass rises out of what was once a catching disease […]

Now I am terrified at the Earth, it is that calm and patient […]

It renews with such unwitting looks its prodigal, annual sumptuous crops,

It gives such divine materials to men, and accepts such leavings from them at last.”

Whitman’s dark, yet strangely reassuring, meditation on the action of soil microbes was penned in 1856, well before the catastrophic events of the 1930s Dust Bowl that saw more than 75% of topsoil lost from areas of the North American and Canadian flatlands. The disaster, which left over 500,000 Americans homeless, intensified the Great Depression and devastated the region’s ecology. It was a direct result of settler farmers’ failure to apply dryland farming methods that would have protected the soil against wind and drought. Instead, deep ploughing to create intensive cropland tore up the native grass cover, leaving soils exposed and friable. The events in the States triggered increased government involvement in land management and soil conservation, with a series of initiatives started in the 1930s that were aimed at reducing soil erosion.

Fast forward to the present day, some 90 years later, and how are our agricultural soils faring? In many areas, particularly in those with a long history of continuous cultivation, the outlook is poor to very poor. Through a combination of factors that include use of synthetic fertilisers and agrichemicals, compaction and removal of organic matter, conventional intensive agriculture is rapidly depleting and degrading topsoil, threatening our capacity to feed ourselves, to control flooding and to lock up carbon in the soil. History offers us countless lessons on the human, ecological and economic suffering that follows poor soil management; it is clear that, after 70-odd years of extractive, chemically dependent farming methods, the warning bells are sounding loud.

The importance of soil management

The FAO estimates that sustainable soil management could enable us to produce up to 58% more food globally. While achieving long-term food security depends as much on reducing waste, enabling food sovereignty and changing diets as it does on increasing yields, the FAO’s findings do highlight how soil health is critical to farmers’ ability to produce enough food. Considering this, farmers need to be equipped with the means to monitor and understand the state of their soils and to be recognised and rewarded for improved soil stewardship. While the Sustainable Farming Incentive offers UK farmers payments for improving soil health, there are calls for more support and incentivisation, particularly in light of the Government’s commitment to ensuring that 40% of agricultural soils are under sustainable management by 2028.

Essential to this is a common language for measuring and valuing soil health. This is something that the SFT is working on through the Global Farm Metric (GFM). Created in collaboration with farmers and other stakeholders, the GFM is a framework to understand, measure and monitor the state of farming systems. It comprises 12 interrelated categories that, when taken together, give a holistic view of farm sustainability. As you might expect, one of the GFM’s 12 categories is ‘soil and water’, reflecting the crucial role of healthy soil within a sustainable farming system.

But how can frameworks like the GFM help us to tackle soil degradation and support farmers to continue delivering the ‘annual sumptuous crops’ described in Whitman’s poem? And who are the farmers that are already leading the way when it comes to a soil-first approach to sustainable production? With these questions in mind, we visited Matt Chatfield on his farm near the Cornwall-Devon border in the UK, where he is harnessing the power of healthy soils to produce world-class mutton and restore wildlife habitats. Matt’s family have farmed in the area for generations, recently struggling in the face of the dwindling productivity and profitability of their land, which Matt is now regenerating through careful soil management.

Matt Chatfield: four questions on soil health

Matt, can you tell us a bit about what you’re doing on your farm to measure and improve the health of the soil and why that’s important?

The number one thing that I’m doing is adding organic matter. My farm had been stripped of organic matter for 40 or 50 years, not due to the fault of any one person, but because of the way that farming has gone. So, I consider my job as being to feed worms – they’re the architects of the soil and they need organic matter to do their job.

The climate is changing. That’s something that is now undeniably noticeable and so I need to adapt my practices accordingly. For example, drier summers mean that worms can’t move through the soil as easily, so where I used to add organic matter in summer, it now makes more sense to do it in autumn and winter when the ground is softer.

Next, it’s building the soil’s capacity to hold water. My method is to let grass grow as long as possible then put the sheep on it for a day or two. The sheep eat what they need while treading down the remaining grass, forming a green cover that protects the soil during the drier periods. This layer helps to prevent water loss as well as providing more organic matter for my worms once the old grass begins to decompose. This approach is really working for me and helped me to get through the drought last year.

How do you think farmers can be encouraged and supported to improve the health of their soils and why do you think they should divert their energy into doing so?

Many farmers are really struggling to make ends meet. For example, one of my neighbours has had to sell his dairy herd recently, and another has now switched to being a feeder system for a bigger indoor dairy unit.

A huge factor that I believe will trigger change is the escalating cost of inputs like artificial fertiliser. When you try to continue farming using conventional methods that don’t build soil health, but you can’t afford to add artificial fertiliser, productivity is likely to plummet. I think this will encourage farmers to try new things. If ‘normal’ farmers like me can show that, through focussing on and measuring soil health, we’re increasing productivity while being more resilient to shocks caused by climate change and input costs, that’s what will make other farmers sit up and pay closer attention to their soils.

However, while improved productivity is an incentive in the long term, farmers need to have the right financial support to enable them to make positive changes to their practices – as well as being a leap of faith, these things cost money and take time.

At the SFT, we’re working to develop the Global Farm Metric, a framework that provides farmers with a holistic view of their farms’ sustainability. What are important considerations when it comes to encouraging farmers to adopt such frameworks?

Overall, I feel positive about the insights that on-farm measurement can provide. For example, I’m working with scientists from the Eden Project to gain a better understanding of how the climate here is changing, so that I can adapt. I’m also working with an organisation that’s providing me with satellite images that show certain biodiversity indicators, so that I can understand how my practices are impacting nature.

On the other hand, many farmers, myself included, have strong reservations about some of the existing and proposed schemes that use sustainability metrics for biodiversity and carbon offsetting, leading to productive land being taken out of farming. In principle, some of these schemes are a fantastic idea, but farmers aren’t always meaningfully consulted for their input and aren’t necessarily the ones who are benefitting.

What I want to see are measurements and frameworks that support nature, helping it to flourish while also supporting farmers to feed people. When farmers feel that they are being listened to and can see the benefit to their profitability as well as to nature, they’re more likely to get on board.

Finally, Matt, what guides your approach to farming: data or poetry?

A good pinch of data and a strong draught of poetry! Data is an essential tool but it’s nature’s rhythms that keep me inspired. When I’m discouraged, I go into my wood. Standing there, or in the fields, nature is always at work and certain truths show themselves: I know that the sun is the fuel, and the ruminant is the engine. At the same time, there is so much that I don’t understand, and that data can’t always account for. As they say, “The more I see, the less I know.”


To find out more about the Global Farm Metric, visit

All images taken on Matt Chatfield’s farm by Charlie Holland. Copyright owned by LONDNR.

Graphic separator Graphic separator