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  • Clare Backhouse

Soil Fungi for future harvests

Last month I promised to tell you why ‘networks of mushrooms underground’ are crucial to what we eat and even the future of our environment. I also made the bold claim that plant-based eating is not, in itself, a diet to solve our environmental problems. It’s time to divulge at last.

First of all, though, I should clear something up. My oldest-friend-in-the-world (we’ve been having tea together since age four) kindly pointed out that I was rather bandying the words plant-based and vegan without defining them. Let’s quickly explain that.

A quick definition - plant-based vs vegan

Plant-based eating means that plant foods have the greatest proportion or focus in the diet. Some people will consistently exclude meat, dairy and eggs, but perhaps retain honey (like Deliciously Ella). For others, ‘plant-based’ means just keeping plant foods as the main part of their diet. So it’s a loose term, seemingly a more fashionable and health-focused one than ‘vegan’, which carries perhaps a slightly more serious, animal-rights-focused connotation.

Veganism aims to avoid any use of animals for human benefit in any way, which means avoiding not just meat/dairy/eggs, but all animal foods, including honey, and all animal-derived products, such as leather, and all animal-connected activities such as horse racing or going to the zoo.

Both veganism and plant-based eating are approaches by which many aim to align their eating towards a healthier planet. People are justifiably horrified by the animal cruelties and environmental crimes perpetrated by the large-scale meat and dairy industries, and envision a world in which widespread adoption of plant-focused diets will contribute towards saving the environment.


The snag with this approach is that it does not take into consideration HOW the plants are grown. As I’ve said before, I don’t advocate one diet for everyone. We’re all different.

But how things are grown, I’m going to argue, does make all the difference to everyone. We could all start a rigorously vegan diet tomorrow, but unless we took this one thing into consideration, we could slide just as fast into environmental disaster.

As I said in my last post, this is all because of soil fungi. Those networks of mushrooms.

Mycorrhizal fungi

‘Mycorrhizal’ fungal networks spread out into the soil, across vast subterranean distances. They are crucial to plant life. Thinner than roots, they can travel more easily through soil and take up its nutrients. They connect with plant roots and exist in a mutually-beneficial relationship with them. A plant’s roots essentially ‘plug in’ to a world-wide-web of fungi below our feet, which is constantly communicating, supplying, interrelating across vast distances.

Mycorrhizal fungi are not currently in the syllabus for most health professionals’ training. This is because we are trained most in consumers’ needs, not the producers’ work. (I would argue this should change.)

I discovered mycorrhizal fungi when I read Robert Macfarlane’s beautiful book, Underland. In it, he describes the existence of these networks amongst trees: ‘an idea so powerful in its implications that it unsettles the ground you walk on’. I would agree with this description!

How do these networks work? It’s a mutually beneficial set-up between the plants and the fungi. Plants photosynthesise sunlight and water into carbohydrates, and their roots share the carbohydrates with fungi, in exchange for nutrients that the fungi can bring to the roots.

Since the fungal network is so horizontally vast, it can draw nutrients from other plants or other soil areas. A plant is even believed to be able to determine the amount of nutrient it wants (phosphorus, for example), simply by adjusting the amount of carbohydrate it releases through the roots to certain fungi.

So a process of beneficial exchange continuously occurs, which not only feeds the plant, but also actually builds the soil. This is because the exchange of nutrients and carbohydrates between plants and microorganisms produces glomalin, a soil-binding protein.

The reason soil sticks to the roots of plants is not because the plant happened to be in the soil, but because the soil was made from the roots of the plant, as it interacted with mycorrhizal fungi.

Thus, mycorrhizal fungi are what create the soil that sticks to the roots of plants, as well as the stickiness that holds it together. Without these fungi, soil becomes dry and dusty and blows or washes away, creating land erosion. And soil erosion – well, this is why there are debates about how many harvests we ‘have left’ to go - before there’s nothing left to grow things on.

Therefore, mycorrhizal fungi and plants together could be said to build and preserve our soil: an essential task for us and for the next generations. It’s tempting to draw a comparison between our gut microbiome and these mycorrhizal fungi which, similarly, ‘infect’ the plants they live on, and yet offer immense benefits.

The final thing I will say in their praise is that their interaction sequesters carbon into the soil. After all, it’s CARBOhydrate that the plant gives to the fungi, which then feeds the whole mysterious network below ground.

Why the fungi are in trouble

But most agriculture, which uses synthetic fertilisers and fungicides, militates directly against mycorrhizal fungi and their benefits, and thereby militates directly against healthy soil. And the future of our harvests. How?

If a plant is sprayed with synthetic fertiliser, it no longer needs to reach out via its root system to acquire nutrients, because it relies on what is sprayed on it instead. It therefore has weaker connections to the mycorrhizal network underground. This in turn means that the diversity of nutrients it might have absorbed through the fungus, is narrower. The plant acquires fewer nutrients.

So the soil suffers, becoming dry and crumbly, providing fewer nutrients, leaving farmers to spray more and more fertiliser to overcome the fundamental ill health of the soil, and more and more pesticide and fungicide because the plants become weaker and weaker against pests. Farming in these soils is almost a kind of hydroponics – everything is artificially supplied. The symbiotic link between plant and land is almost severed.

Such farming is of course highly damaging to the environment. In addition to soil erosion, the toxic run-off from all the chemical sprays contributes to the pollution of rivers and to the deaths of all sorts of insects (including pollinators) and fish.

Thus, one could be a strict vegan and yet have one’s diet supplied in such a way that it actually contributes to environmental disaster. Presumably this works very nicely for those companies which supply the chemical fertilisers, pesticides and fungicides to grow most of our plant foods.

How our food choices could benefit the land

The key difference, is organic farming and food. Organic food is grown without chemical fertilisers and with radically reduced pesticides, using zero genetically modified crops. This means that farming HAS to rely on these mycorrhizal networks to supply nutrients and create healthy plants.

Although there are many ethical farmers who don’t yet have official organic certification, organic is currently the only ‘label’ that can guarantee that your vegetables, pulses and grains were grown in a way that built up the land instead of damaged it:

The benefits of organic farming are in fact the reason I don’t agree with George Monbiot’s vision of a future with lab-grown food. Artificial food growing ignores the concept that the methods with which we produce food, far from being inevitably detrimental to the Earth, have the capacity to build up the health of the land, sequester carbon, and prevent soil erosion.

Organic methods, by building the soil, are the basis for sustainable farming – that is, creating a way of providing food for ourselves that is a win for the environment, a win for animals, and a win for ourselves, in the long term.

So if you are leaning towards plant-based eating, or veganism, in order to support the environmental future of the planet – and indeed, even if you aren’t doing any of that - may I propose that you consider organic food more seriously.

After all, healthy soils now are what create healthy harvests for the future. At whatever scale organic food is feasible for us, whether large or small, we can all buy into that.

Another time I’ll talk more about organic food and how to source it affordably.

But for now, let me wish you a very happy, peaceful, virus-free month.

To your best of health,


Clare Backhouse, dipION, Registered Nutritionist MBANT,

Registered Nutritional Therapist CNHC

Consultations in London, in West Sussex, and online

PS anyone else out there who’s grieving, you might find Cariad Lloyd’s ‘Griefcast’ podcast helpful. I discovered it last month:

It describes itself as ‘a podcast that examines the human experience of grief and death - but with comedians, so it’s cheerier than it sounds’. I liked the latest one with Charlie Mackesy.


Bonfante, P., Genre, A., 2010. Mechanisms underlying beneficial plant–fungus interactions in mycorrhizal symbiosis. Nature Communications 1, 1–11.

Egerton-Warburton, L.M., Querejeta, J.I., Allen, M.F., Finkelman, S.L., 2013. Mycorrhizal Fungi, in: Reference Module in Earth Systems and Environmental Sciences.

Food and Agriculture Organization of the United Nations, 2020. Soil biological management with beneficial microorganisms Plant Production and Protection Division.

Gorzelak, M.A., Asay, A.K., Pickles, B.J., Simard, S.W., 2015. Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities. AoB Plants 7.

Kennedy, A.C., de Luna, L.Z., 2005. Rhizosphere, in: Hillel, D. (Ed.), Encyclopedia of Soils in the Environment, 399–406.

Panagos, P., Borrelli, P., Poesen, J., 2019. Soil loss due to crop harvesting in the European Union: A first estimation of an underrated geomorphic process. Science of The Total Environment 664, 487–498.


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