Soil

Soil is the source of our food and the foundation of our natural environment, but our soils are threatened by challenges from climate change and intensive agriculture. Farmers face pressure to produce more food at lower prices, increasing dependency on artificial fertilisers and mechanisation. In turn, this can disrupt the beneficial microbial networks and damage the physical structure of healthy soil.

Healthy soils and sustainable agriculture are intimately connected with our natural water systems, affecting water quality and soil’s capacity to moderate the impact of extreme weather conditions – drought, rainstorms and flooding, which are set to increase as a result of climate change.

  • Intensive agriculture can cause arable soils to lose 40 to 60% of their organic carbon.
  • There is a lack of data on the health of our soils and more investment is needed in soil monitoring.
  • Soil degradation was calculated in 2010 to cost £1.2 billion every year in the UK.
  • Almost 4 million hectares of soil are at risk of compaction in England and Wales, affecting soil fertility and our water resources, and increasing the risk of flooding.
  • Over 2 million hectares of soil are at risk of erosion in England and Wales.
  • Soil biodiversity and the many biological processes and soil functions that it supports are under threat.
  • Food waste and bioenergy demand are putting additional pressure on soils.
  • UK soils currently store about 10 billion tonnes of carbon, roughly equal to 80 years of annual UK greenhouse gas emissions.

Environment Agency – state of our soils

Biochar

Our Biochar is made by turning waste wood from Flete Estate’s normal woodland management processes into biochar – discovering the best methods for mid-scale production and working with an Exeter Retort to help other Devon landowners/farmers apply local, circular, low impact practices to improve run off, soil quality and sequester carbon.

Biochar is a form of wood-based charcoal, prepared specifically for use as a soil improver, which provides many benefits in the soil; it can improve water management, reduce soil compaction, enhance nutrient retention, and stimulate beneficial soil microbes. However, perhaps most importantly, it has huge potential as a greenhouse gas removal technique. It is a method of literally capturing carbon from the air, and locking it back into the ground, without complex and energy-hungry technological infrastructure.

Biochar’s benefits to soil, plant growth and crop yield have been demonstrated in many laboratory studies, in gardens and in field trials around the world. However, the benefits are dependent on many factors, including the type of biochar, the soil type, climatic conditions and the crop grown. Field trials in the UK are sparse and evidence for Devon’s soils and climate are lacking. In particular, we acknowledge that increasing uptake of biochar in agriculture will be dependent on practical methods of production and application, and verification of benefit in-the-field.

We are working with farmers, students, volunteers and the local community to develop methods to produce and apply biochar, to test practicality and scalability, and to produce valid science supporting its value to soil health and productivity.

Biochar production and research projects

Over 2022 and 2023 we have delivered three biochar-based MSc. research projects with Plymouth University students and The Flete Estate:

  • Aaron – combined mycofiltration and biochar for water remediation (lab-based)
  • Chinedum – biochar effect on soils in permanent pasture and lab
  • Nasiru – soil physical and chemical parameters using NIR scanner

In addition, we have run two further trials, on the use of microbially-activated biochar in cultivated soil, and use of mycofiltration and biochar to remediate dairy waste water pollution.

So far we have produced over 1000kg of charcoal in our Exeter Retort, using waste biomass from woodland management on and around the Flete Estate, equivalent to 3000kg of carbon dioxide removal. For 2024, we aim to produce and process at least five tonnes of biochar, and apply it in the field with supporting scientific research on its benefits.

‘On land, all life springs from soil. Soil is ecological currency. If we overspend it or deplete it, the environment goes bankrupt….. Mycorestoration is the use of fungi to repair or restore the weakened immune systems of environments.’

Paul Stamets – Mycelium Running