The role of soil in regenerative agriculture

Regenerative agriculture has the potential to increase the UK’s climate resilience and address food insecurity. Through modern knowledge and ancient wisdom, farming can revolutionize the fight against climate change, biodiversity loss, and eutrophication of rivers through nutrient runoff. By restoring, not conserving, we can create a fruitful future for farming.

In today's agricultural landscape, the traditional principles of natural return have been eclipsed by the imperative of maximizing output to sustain a rapidly expanding global population; a shift that gained momentum in the 1940s under the War Agricultural Committees which fundamentally changed modern farming¹. Use of fertilizer is common practise and forests were reduced to 1% of land cover in 1998². The result of this shift has led to concerns such as environmental pollution and soil degradation. Additionally, local farmers, who have been stewards of generational land, find themselves facing challenges from conflicting interests; caught between regulatory compliance and the challenges of an unfair market.

Restoring the balance

The answer lies in the beautiful balance of soil biota. Traditional ploughing (tilling) destroys soil biota’s natural balance by physically shredding the structure of the soils that allow life to thrive. This makes use of expensive input fertilizer, pesticide, and fungicide necessary to produce food in unbalance soils. Fertilizers applied to a field can incur losses of up to 40% due to rainwater runoff that ends up in rivers³. Such an approach appears futile, and moreover, detrimental, considering that the soil already contains the essential nutrients for plant growth.

In idyllic soils, the color should be black with organic carbon and wriggling with life. It’s the small invertebrates, worms, nematodes, bacterial protozoa, bacteria, and fungi (to name a few) that breakdown materials and promote healthy plant growth. Mycorrhizal fungi are the critical interface between plant and soil that are the key to the soil plant interface⁴. Carbon is sequestered from the atmosphere and is fed to the fungi as sugars, in return, nutrients are supplied to the plant and is protected from diseases.

Mycorrhizal fungi also form the ‘wood wide web’ in the soils which adds structure and resource allocation whilst significantly contributing to overall biomass⁵. This matrix allows organisms to live in a healthy balance where the soils can accumulate carbon from the atmosphere through the plant lifecycles⁶. Here lies the true value, soils can extract carbon from the atmosphere at a scale better than current technology. This helps us achieve climate goals whilst providing food security, flood resilience, and nutrient neutrality without radical changes to conventional farming⁷.

Achieving a sustainable future

With UK (Carbon) Emissions Trading Scheme markets and biodiversity net gain (BNG) credits, there is an underutilised opportunity for farmers to access finance through offset that can directly regenerate the landscape⁸. This can be partly attributed to ‘convoluted, burdensome, and unpredictable nature of receiving offset credits’⁹. When the soil can heal, so will the water through reduced eutrophication, with little need for direct input¹⁰.

It is envisaged that, with rapid advancement in fungi research, specialist mycorrhizae could be cultured on farms then used with direct seed drilling equipment to effectively inoculate soils in-situ. The theory is by restoring the soil matrix, the natural balance can be restored quicker and still produce output for the farmer’s business. Over time, with crop rotation and no-till, costs will plumet; a Swiss research paper found that inoculating soils could increase yield by up to 40%¹¹. Though understanding the unique nuisances of each farm will require considerable research and collaborative approaches for effective implementation.

To achieve sustainable and regenerative agriculture, case studies in action are needed, so that the new farming policy and subsidies are comprehensive and serve small holdings and their communities. This is not solely about organic practices; rather, it's about enabling farming to become a viable and profitable business for farmers in a practical and expedient manner. An added bonus is our land can become brilliant with colour and full of life, by paying attention to the microorganisms in the soil.

This guest editorial was written by Christopher Middleton, Graduate Hydrologist, CIWEM

References

1. Short B., (2007) War in the Fields and Villages: The County War Agricultural Committees in England, 1939–45. Rural History. 2007;18(2):217-244. doi:10.1017/S0956793307002166

2. Reid, C., Hornigold, K., McHenry, E., Nichols, C., Townsend, M., Lewthwaite, K., Elliot, M., Pullinger, R., Hotchkiss, A., Gilmartin, E., White, I., Chesshire, H., Whittle, L., Garforth, J., Gosling, R., Reed, T., & Hugi, M. (2021). State of the UK's Woods and Trees 2021. Woodland Trust.

3. Allison, R. (2019) '6 steps to improve your fertiliser use efficiency', Farmers Weekly, available at: https://www.fwi.co.uk/arable/crop-management/nutrition-and-fertiliser/6-steps-to-improve-your-fertiliser-use-efficiency

4. (AHDB) Agriculture and Horticulture Development Board, (BBRO) British Beat Research Organisation,. (2023). Principles of Soil Management. Agriculture and Horticulture Development Board

5. Simard, S., Perry, D., Jones, M. et al. Net transfer of carbon between ectomycorrhizal tree species in the field. Nature 388, 579–582 (1997). https://doi.org/10.1038/41557

6. Heidi-Jayne Hawkins, Rachael I.M. Cargill, Michael E. Van Nuland, Stephen C. Hagen, Katie J. Field, Merlin Sheldrake, Nadejda A. Soudzilovskaia, E. Toby Kiers. (2023). Mycorrhizal mycelium as a global carbon pool. Current Biology, [33][11], R560-R573. https://doi.org/10.1016/j.cub.2023.02.027

7. Montgomery, D.R. (2017). Growing a Revolution: Bringing Our Soil Back to Life. W.W. Norton & Company.

8. DEFRA, (2023) Collection Biodiversity net gain [online]. Available from: Biodiversity net gain - GOV.UK (www.gov.uk)

9. Barbato, C.T., Strong, A.L. Farmer perspectives on carbon markets incentivizing agricultural soil carbon sequestration. npj Clim. Action 2, 26 (2023). https://doi.org/10.1038/s44168-023-00055-4

10. Boehm, Rebecca. 2020. Reviving the Dead Zone: Solutions to Benefit Both Gulf Coast Fishers and Midwest Farmers, Cambridge, MA: Union of Concerned Scientists. https://www.ucsusa.org/resources/reviving-dead-zone

11. Lutz, S., Bodenhausen, N., Hess, J. et al. Soil microbiome indicators can predict crop growth response to large-scale inoculation with arbuscular mycorrhizal fungi. Nat Microbiol 8, 2277–2289 (2023). https://doi.org/10.1038/s41564-023-01520-w