Soil is a precious resource and takes thousands of years to form. But today, the degradation of that resource is a critical and growing global problem, with increasing world population adding to pressure on soil, whilst its value (its ‘natural capital’) faces continuing decline.
To address this issue within this European Union, the Waste Framework Directive sets the following waste hierarchy to be applied as a priority order in member states:
- prevention
- preparing for reuse
- recycling
- other recovery and disposal.
As such, disposal to landfill is the least favoured option, meaning that a large amount of biodegradable waste must be diverted from landfills to other organic waste management practices, where it can be recovered and utilised.
Soils can be manufactured from waste materials and products generated are generally appropriate for urban development and landscape management, such as green areas, and as high-value substrates. A sustainable manufactured soil must match most of the properties of naturally-generated topsoil.
These include providing nutrients for plant growth, whilst also maintaining biological populations and nutrient retention capacity to balance losses incurred through processes such as leaching. For example, nitrogen limits productivity in most terrestrial ecosystems so one of the most significant requirements for an effective longer-term growth medium is its ability to retain, store and release this element as required to support plant growth cycles.
The FABSOIL project, which is supported by the Agri-Tech Cornwall project, has the aim of manufacturing and optimising a soil from suitable waste materials that can perform at least as well as natural topsoil, while acting as a sustainable substrate in any environment to which it is deployed; this could include production of specialist crops, urban development or even increasing soil coverage in private residence.
FABSOIL builds on a collaboration between the Sustainable Earth Institute and The Eden Project, in Cornwall, where a PhD studentship awarded through the European Social Fund enabled us to comprehensively study the sustainability of soils manufactured and deployed by the Eden Project since 2001.
“FABSOIL will allow us to build our knowledge of both the cycling of key chemical components of the manufactured soils, and the evolution and characteristics of the biological community, which is critically important.”
Fungi and worms have a higher carbon demand than bacteria so the soil composition and management must account for changes in the balance of these populations. Our expertise in this area and recent findings have generated one of the first publications on the biogeochemistry of manufactured soil and we see a great future for FABSOIL as both an area of research and a sustainable product to mitigate current and future pressures on a precious resource.
