We should all be obsessing over the magic of soil

Spend It Better: Good soil captures carbon, grows healthy, tasty food and contains microbes that can’t be reproduced in a lab

I was always going to be drawn to the work of a former restaurant critic turned farmer who’s obsessed with soil. And you should be too. Matthew Evans took a Cinderella subject and wrote Soil, the Incredible Story of What Keeps the Earth, and Us, Healthy. The brown stuff contains at least one bacteria that works as an antidepressant, he wrote. Our microbiome is intrinsically linked to the ecosystem that provides 98 per cent of the food we eat.

Soil geeks are obsessive and curious because there is still so much to know. Fewer than 1 per cent of the microbes living in soil can be cultured in a lab. They are the dark matter that truly matters. A little more than a century ago, German chemist Fritz Haber won a Nobel prize for a method of fixing nitrogen into synthetic fertiliser, which is still used to produce about 100 million tonnes a year.

But we have to wean ourselves off synthetic fertilisers. They are produced using fossil fuels. They release nitrous oxide a gas 300 times more warming than carbon. Run-off into our waterways is causing huge problems. And the drawback we talk about least? Haber’s magic bullet is killing soil life.

‘Soil medicine’

There are home-grown alternatives. Louth beef farmer and entrepreneur Anthony Woods modestly calls his Super Soil product (supersoil.ie) "the world's best fertiliser". One hundred grams is enough for an acre, he says. Boosting the life in the soil can create a huge potential carbon sink drawing the greenhouse gas down into the darkness where it belongs, while producing healthier food. Woods says he has seen his grass growth thrive and believes it works both as fertiliser and "a sort of soil medicine to kick off a natural microbiome".

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Soil life can also benefit from waste materials. The Cork Urban Soil Project (CUSP, urbansoilproject.com) grew out of a festival experiment by My Goodness, the probiotic food company in Cork's English Market. Virginia O'Gara began the project with Molly Garvey and humanitarian Sean Binder in 2018 after a successful zero-waste trial at Body & Soul.

She believes “the problem is the solution” when you turn food waste into a nutrient source rather than a pollutant. All their food waste goes into a biodigester combined with shredded cardboard to make compost in just four weeks. The machine seals in odours and is rodent-proof and perfect for urban composting. The next stage will be taking on an unpromising patch of urban ground beside them to grow food with their peat-free compost. “It’s a very scaleable project,” O’Gara says. Cafes and householders could compost in districts and distribute the crumbly black stuff of life to community projects.

Close the loop, capture carbon and grow healthy, tasty food. What’s not to obsess over?

Catherine Cleary is the co-founder of Pocket Forests