Underfoot, yet overlooked: Why the world as we know it depends on soil

Soils are in trouble and not enough people seem to be noticing. Even the UN’s Year of the Soil in 2015 seemed to pass by much the same as any other, with many of us oblivious to the slow degradation going on under our feet. We don’t give our soils the attention or affection they deserve – after all, only most terrestrial ecosystems, our entire agricultural system, and therefore our very existence itself, depend on them…

A decade ago the Stockholm Resilience Centre devised the idea of Planetary Boundaries. These are nine crucial measures that inform us about the ecological health of the planet and thereby describe a ‘safe operating space’ for humanity. The Earth is a finite system so these Planetary Boundaries are basically a refined form of describing a carrying capacity.

The boundaries chosen were: climate change, biodiversity, nitrogen and phosphorous cycles, ocean acidification, land use, freshwater, ozone depletion, atmospheric aerosols, and chemical pollution. A worthy list of complex contemporary problems, I’m sure you’ll agree. There’s only one thing missing – soil.

Part of the problem is that to the untrained eye a soil is a soil is a soil. Most people have no way of discerning good from bad, healthy from sick. Another, is that soil degradation often follows in the wake of some other ecological wound. We’re aware of the obvious destruction of a rainforest, but not the topsoils that wash away after the trees are gone.

The UK has lost almost 85% of its fertile topsoil in the past 250 years. Natural soils take a long time to develop and are very difficult to replace – it can take a thousand years to form 1 cm of soil – so this loss matters.

Eden’s long history with soil goes back almost 25 years to the time some bright sparks had the audacious idea of growing a global garden in the crater of an old clay pit. Bodelva Pit may have been dripping with all the landscape drama of a Lost World, but it was completely lacking in soil – crucial for a place that intended to showcase plants.

A team of scientists was enlisted to solve the problem. Led by Dr Tony Kendle, then at the University of Reading but soon to join Eden as a director, and assisted by Drs Juliet Rose and Pete Whitbread-Abrutat they set about one of the largest soil creation projects the world had seen. A nearby clay pit was used as a giant mixing bowl in which sands, clay wastes and organic matter were blended in a range of recipes to suit plants from tropical rainforests through to semi-arid deserts. In the end, they made 83,000 tonnes of the stuff, literally ‘brown gold’ for a project which has always had astonishing horticulture at its core.

As a historical side note, this work might not have been possible were it not for the work of Tony Kendle’s PhD supervisor, Professor Tony Bradshaw of Liverpool University, half a century earlier. Bradshaw’s pioneering work on the revegetation of china clay wastes in the 1950s and ’60s was crucial to the success of Eden all those years later.

Anon

“ Despite all our accomplishments, we owe our existence to a six-inch layer of topsoil and the fact it rains. ”

Soil is the ultimate blend of rock, water, air, the dead and the living. It’s our mineral nutrient supplier, water reservoir and climate regulator – it stores over 10 billion tonnes of carbon. Under our feet lives a complex community of minibeasts, microbes and moles. I like to think of soil as the great unifying force. Without it, it’s hard to make sense of many of the planetary boundaries, indeed it’s hard to make sense of any socio-ecological issue at all. Without soils how could one begin to have a sensible conversation about rainforests, agriculture, food security or climate change?

It is estimated that a third of agricultural lands are already degraded. There was no greater project in the 20th century than feeding the world’s growing, modernising population, but now we understand it’s come at an ecological cost.

Because of this, we’ll find today’s superheroes out in the fields – where they’ve always been. Farmers all around the world are increasingly farming with ecological gains in mind and this quiet revolution goes by the whispered name of regenerative agriculture. Regenerative agriculture is a broad church so consensus can be elusive; however, Nick Jeffries of the Ellen MacArthur Foundation describes regenerative agriculture as, ‘…a broad set of food production methods with two clear and complementary outcomes: the production of high-quality food and the improvement of the surrounding ecosystem’, and that pretty much sums it up. Essentially it means farming with nature in mind, giving back more than we take.

Across Cornwall 65 farms of all types have joined The Soil Carbon Project, to understand how their soils store and build organic matter over time. Organic matter improves the quality of the soil as well as helping store water and carbon. Alex Bebbington of Agritech Cornwall who runs the project, said, ‘The government target is 3% organic matter, we can smash that down here!’

One farmer already smashing it is Chris Jones of Woodland Valley Farm near Ladock. In the decade since going organic, Woodland Valley has doubled its organic matter to 9.5%. Chris told me: ‘We are in the grips of anthropogenic climate change and the sixth mass extinction so where possible we must use land in ways that sequester carbon. This includes grazing animals, it means no-till, it means organic, and it means farming and forestry that is suited to local ecologies.’

Another famer recently embarking on the soil carbon journey is Matt Chatfield, who runs the Cornwall Project, aiming to connect Cornish produce with high-end London restaurants. Matt’s soils were sampled under the Soil Carbon Project and the results were extraordinary, maybe indicating a history of mixed farming on his land. ‘Restaurants have been concerned that they were contributing carbon to the atmosphere, but they can now be proud [of] how much carbon is being stored in the ground,’ Matt said.

Agritech Cornwall also fund one of Eden’s exciting soil projects, Fabricated Soils (FabSoil). It picks up where Tony Kendle and co. left off twenty years ago, investigating the creation of novel soils from waste material. These soils can then be applied to all sorts of contemporary challenges from urban land reclamation to specialised crop production.

Bringing the world’s soils back to life surely ranks as one of the great endeavours of our time. And if we do it, we could secure the world’s food supply, suck carbon from the atmosphere and boost biodiversity, among other things. Doing it will take a suite of approaches; it is the very definition of a transdisciplinary project. With science providing the knowledge pathways and increasing numbers of farmers like Jones and Chatfield invested in soil health, I think there’s much to be optimistic about.

Some of Eden’s soil projects

FabSoil is funded by Agritech Cornwall, and is a collaboration between Eden Project and the University of Plymouth aiming to make soil material from recycled and waste materials, including composted green waste, clay, grit and bark, ensuring it’s stable and fertile, while maintaining a reservoir of slow-release nutrients to fuel plant growth without the high demand for fertiliser. Artificial soils have many potential uses, from landscaping and urban restoration to landfill and high-value crop production. It brings the possibility of custom-made soils, of varying characteristics, being designed to order for various purposes across a range of locations and markets.

Improving Environmental-DNA (e-DNA) Detection in Novel Soils for Biodiversity Assays – is a project run by Dr Julian Donald at Université de Toulouse. Instead of looking for individual species in the soil, the project will use e-DNA detection to create a profile of that soil which can be compared with what’s growing above ground, and identify the effect of climate, soil and plant species on the persistence of e-DNA within a soil.

The Sustainable Soils Alliance was formed in 2017 in response to the increasingly urgent need to address the issues of soil holistically. Eden is a founding partner, supporting SSA to achieve maximum impact. SSA’s role is three-fold. It is a convening organisation for the community of individuals and organisations interested in sustainable soils, a campaigning organisation monitoring the government’s progress in developing policies and calling to account when it falls short, and a coordinating organisation for the wealth of relevant information.