13 minute read
Breaking new ground
Soil holds life together. It also holds together professions across the built and natural environments and demands that we work collaboratively to ensure that we value and restore our soils, helping them to help us. Here, President of the Landscape Institute, Carolin Göhler FLI, introduces voices from across the industry to spotlight soil’s wide-ranging importance, and just a small amount of the current work taking place.
Carolin Göhler FLI President, Landscape Institute
For some people it is ugly dirt, but soil really is beautiful: our true gold. It is even more precious now than we previously thought, as our growing understanding of it highlights the incredible benefits for people as much as for nature – if we look after it.
Throughout my career in horticulture and landscape, I have witnessed our understanding and awe of this complex underground ecosystem multiply. Not only is soil health important for healthy plants, but it also reduces the need for artificial fertilisers (along with their greenhouse gas emissions (GHG)). It acts as an important water store, retaining excess water like a sponge, and thus plays a valuable role in flood reduction. A healthy soil prevents erosion, reduces the need for irrigation during drought situations, enhances biodiversity, and is up to three times more effective at carbon sequestration than the plants and atmosphere above the surface.
Soils’ natural capital supports most life on earth and plays a vital role in supporting multiple UN Sustainable Development Goals. Sustainable land management practices that work with nature to maximise soil performance, such as regenerative farming, could enhance crop yields and support healthier and enhanced food systems.
Increasingly, we are learning that lighter-touch management, such as low or no-till and no-dig methods, conserves the soil’s structure and its natural ecosystem of roots, fungi, and microbes. This regime also allows, for example, worms to be the incredible experts at recycling, nutrient dispersal and drainage that they are, continually improving the quality of any soil.
Creating and maintaining high-quality soils in urban environments requires a thorough understanding, not only of soil as a system, but also of technological advances. These include growing substrates and soil reuse, with the implementation of such advances bringing new life to degraded landscapes. While improved specification is underway, we must stop prescribing peat in any soil mixes (including pot-grown plant purchases) to make a positive climate impact and preserve rare wildlife habitats.
In both domestic policy and international forums such as COP (UN Conference of the Parties), a focus on soil has largely been absent. This is despite its critical role in human prosperity, as both a powerhouse in the carbon cycle and a key player in biodiversity conservation. We all have a duty to protect and improve soils, taking as many people as possible with us on the journey to understand, protect, and enhance our soils to benefit current and future generations. All of us, including landscape professionals, must collaborate more across the built and natural environment sectors, invest in soil health, and start valuing soils in a way we never have before. The health of society, as much as the beauty of our landscapes, depends on it.
From microscopic to landscape scale
Paul Hallett FI Soil Sci. President, British Society of Soil Science (BSSS)
Landscapes are built on the soil that arises from the geology underfoot, its weathering, and the driving forces of the life it supports. This creates huge complexity across natural landscapes but, in constructed landscapes, the greatest driving force of life can be the landscape professional overseeing the treatment of this precious resource.
Good landscapes promote biodiversity, including in the soil, with microorganisms and plant roots working in tandem to aggregate soil into beneficial biological habitats that balance water drainage and storage (Figure 1). Poor management – from compaction, mixing topsoil with subsoil, or stockpiling – leads to degradation of the soil’s biological habitat. Not only can this hinder biodiversity both below and above ground, but vital functions of landscapes such as drainage, amenity use, and the sequestration of atmospheric carbon will also be harmed.
Soil scientists use a range of tools to assess biological health in landscapes, ranging from simple visual assays accessible to all, to sophisticated explorations of microbial diversity through DNA analysis and 3D biological habitats in soil pores using X-Ray CT. When landscape professionals invest in good soil health through an understanding of the science, the benefits are extensive. Savings are made through reduced fertiliser use and irrigation demand, enhanced environmental benefits are realised from minimised flooding and increased carbon storage, and the outcome is happier clients.
Why microbes matter
Dr Marc Redmile-Gordon Senior Scientist for Soil and Climate Change, Royal Horticultural Society (RHS)
A healthy soil delivers vital ecosystem services, from methane removal to water storage. An aggregate held between your fingers is teeming with life and can house more microbes than the number of people living in London. Some cells live on their own, others cluster into groups called biofilms, but nearly all contribute to soil health. Microbes make sticky substances, called extracellular polymers, that improve soil structure and prevent erosion. A healthy soil has an open structure, both transmitting and storing water, that in turn protects our plants, soils, rivers, and water quality.
The RHS’ Soil Health Platform at Wisley supports investigations into soil health generation. Its aim is to help the UK become more sustainable by communicating our research and advice into climate mitigation and the value of different carbon pools and storage times. Treatments under investigation will include soil management practices, soil improvers, biostimulants, plants, and plant-products.
Parties interested in collaboration are invited to contact the author at Marc.Redmile-Gordon@RHS.org.uk.
Soil and water
Alastair Chisholm Director of Policy, Chartered Institution of Water and Environmental Management (CIWEM)
As our climate changes, the role of soils as a crucial carbon sink will become more pronounced. Consequently, their ability to buffer against the effects of climate change will also become more important, not only to maintain agricultural productivity but also to maximise resilience to extremes of weather –both flood and drought.
Soils currently account for approximately 37% of water storage capacity in the UK. Many are not in good health or as spongy as they could be. That percentage would increase with good stewardship and restoration through more regenerative agricultural approaches. Those in the know suggest that with better soil stewardship, the UK could enhance its food productivity despite climate change. Both studies and anecdotal evidence demonstrate that, in dry weather, regeneratively managed soils with increased organic matter content achieve elevated crop yields.
A UK-typical 86-hectare farm could store 67,000m3 more water if regeneratively farmed, shielding downstream communities from flash-flood runoff commonly experienced with compacted soils that infiltrate water at a snail’s pace. This would also make more water available to nature in times of drought by sustaining vital base flows. Sponge soils really should be a no-brainer. We’re going to need them.
The role of soils in BNG
Dr Mark Nason MCIEEM CERP MI Soil Sci.
Head of Professional Practice, Chartered Institute of Ecology and Environmental Management (CIEEM)
Biodiversity Net Gain’s 30-year monitoring and management requirement highlights the need to focus on soil resources, as ecologists need to match habitat requirements to soil characteristics. They must also collaborate from the outset with soil scientists, landscape architects, and other stakeholders to consider complementary expertise and evidence, including knowledge of local soils and ecology. Failure to do so risks missing opportunities to identify, protect, and optimise the use of soils and soil-forming materials that may result in the recommendation of habitats that can’t be created, or the creation of habitats that can only be sustained through excessive management. Helping practitioners access guidance and tools to support evidence-based approaches and foster collaboration are key priorities for CIEEM. Our updated guidelines for Ecological Impact Assessment (EcIA) provide more advice on how soils should be considered, and we’re producing a new ecological restoration series with contributions from soil scientists and landscape architects. We’re also creating a biodiversity overlay for the RIBA Plan of Work as a tool to support multidisciplinary collaboration and help professionals deliver more for nature and people, from the ground up.
Right soil, right land use
CPRE, the Countryside Charity
Graeme Willis Agricultural Lead
There is growing pressure on land, with geopolitical instability and climate volatility driving increased incidences of flood, drought, and fire. This perfect storm of factors is undermining the certainty of how and where we can produce food in future, and in what quantity. Hence CPRE’s call for a stronger national planning policy to protect the best farmland and the most productive soils from built development is now an urgent imperative. Sadly, recent governments have instead consistently weakened the policy in order to drive short-term economic growth.
More positively, farmers are beginning to tap into the potential of regenerative approaches to reverse decades of soil neglect and harness natural processes to drive better land management. But to fully future-proof our domestic food supply, we must protect the extent of our best farmland soils and manage them back to health. We need the right policies on soils to be supported by investment in better tools and evidence. CPRE has recently demonstrated that a review of one key tool – the Agricultural Land Classification (ALC) system – is essential. A revised and updated ALC should provide the evidence to underpin the government’s much anticipated Land Use Framework and other relevant planning and farming policies.
Towards soil reuse
Rachel Boulderstone
Head of Soil Health and Contaminated Land Policy, Department for Environment, Food & Affairs (Defra)
At Defra I oversee many aspects of soil health and contaminated land, focusing on the importance of healthy, resilient soil and ensuring we protect and reuse soil sustainably.
I am particularly interested in surface water flooding caused by compaction and believe correct practice that is relevant to soil type and land use is vitally important to support production, nature, and the environment.
In 2022, 24.7 million tonnes of soil were disposed of in landfill by the construction sector in England, making up nearly 60% of all waste sent to landfill. This was largely because soil reuse is not typically planned sufficiently early in projects, the soil itself can become compacted or degraded during earthworks, or it is not the right type for the scheme.
Defra’s Environmental Improvement Plan set a commitment to develop a Soil Reuse and Storage Depot scheme. The aim of this is to reduce the amount of soil going to landfill, facilitate appropriate soil storage, and encourage soil reuse. Following on from the recent Environment Agency report on its potential, I am planning further research that will inform the scheme’s development. The scheme will allow landscape architects to make recommendations to clients when soil reuse on site is not possible.
Integrated policy required
Joseph Lewis Policy Lead, Institution of Environmental Sciences
The importance of a holistic approach to soils is very clear: soil touches all aspects of the natural world and demands a joined-up response.
Soil is vital for carbon sequestration and can buffer against the effects of climate change. Healthy soils are also fundamental to ecosystems, supporting their biodiversity, nutrient cycling, and resilience.
Beyond their role in natural systems, soils are also deeply embedded in human systems. Soil is essential to the vast majority of food production and delivers substantial cultural and economic benefits.
Soils determine where we can build, and planning processes often contaminate soils or cause them to become waste. However, nature doesn’t recognise the boundaries we put on maps or the rings we draw around government departments. Some policy areas receiving the greatest benefits from healthy soil are inherently detached from the processes that determine whether those benefits are delivered, so a joined-up approach is essential.
Diverse planting for more resilient soil systems
Sheila Das Head of Gardens and Parks, National Trust
Public gardens can play a key role in demonstrating healthy soil management. For instance, conventional approaches have relied heavily on the use of bulky organic matter mulches such as manure or composted green waste. However, on-site composting, ‘chop and drop’ techniques, green manures, and living mulches can all be employed to reduce external inputs that are both costly and carbon heavy.
The move away from monoculture plantings and the introduction of a diverse range of plant roots in soils are supportive of soil biology. A range of root types (e.g. tap, fibrous, rhizomatous) and a selection of plant families (mixing woody and herbaceous for example) leads to an underground diversity that helps build a more complex and resilient system where nutrients are cycled in perpetuity.
The National Trust is experimenting with the management of rose gardens, adding varied underplanting to avoid the soil ‘sickness’ typical of conventional monoculture rose gardens (more accurately described as an unbalanced soil microbiome). Observing and responding appropriately will be key to enjoying such features in the future without the use of pesticides. This requires an aesthetic shift, so communicating actions to visiting members of the public and ensuring we take people along on the journey will be key to success.
Collaborative working
Ellen Fay Executive Director, Sustainable Soils Alliance (SSA)
Recognising that soil supports all life on earth and yet is undervalued, the SSA is a soil-specific organisation working to align voices across policy, business, and the land management sectors.
Statistics on soil are revealing: UK soils store an estimated 130 trillion litres of water; more living things are found in one teaspoon of soil than there are people on the planet; and soil also acts as the second-largest global carbon sink. Despite the critical roles that soil plays, in 2022 soil carbon losses due to urban development were estimated at 6.1 million tonnes.
By bringing diverse stakeholders together to address soil degradation and advocating for effective, collaborative solutions, the SSA bridges the gap between landowners and managers, leading soil scientists, and businesses. To this end, the SSA aims to embed soil health in sustainability goals that are aligned with on-the-ground practices, helping stakeholders understand the importance of soil health in achieving broader environmental objectives. Through educational initiatives, policy advocacy, and partnerships, the organisation encourages investment in soil protection and restoration for the delivery of mutual benefits, such as increased productivity, safeguarding carbon, and more resilient ecosystems.
