Soil

24 November 2021 | Posted in Charlotte Owen , Plants
Soil
Earthworm © Derek Middleton

By Charlotte Owen

WildCall Officer

For such a visual species, we’re not always very observant. Nature often blends into the background unless it’s something unusual, brightly-coloured or fast-moving that demands a closer look. The common, everyday and ordinary may barely register. Our brains are wired to stop noticing things that remain unchanged, to filter out background noise and overlook anything that isn’t immediately relevant. We’re so good at not seeing what’s right in front of us, it’s no wonder we don’t notice the things that really are hidden – even when they’re fundamental to our very existence.

Soil is a perfect example. It might be paved over in places or covered in tarmac but there’s a secret world beneath your feet. Scoop up a single teaspoon-full of soil and you’ll be holding more organisms than there are people on the planet (7.7 billion and counting). This incredible abundance of life is hugely diverse, and the same teaspoon of soil could contain 10,000 different species. Many are microscopic and most are tiny, from single-celled protozoa to bacteria and fungi, springtails, mites and nematodes. We’re more familiar with the comparative giants of the soil-scape, the centipedes, millipedes, beetles and earthworms, pursued by gargantuan moles and other fossorial creatures.

The soil they live in is a mixture of organic matter, minerals, air and water. Its precise composition depends on which weather-beaten rocks were ground down over thousands of years to form tiny grains of silky silt, gritty sand or sticky clay. At the microscopic level, these soil particles form boulders, fissures and water-filled caverns, cemented by humus and stabilised by the gossamer threads of fungal hyphae. This miniature maze is constantly re-modelled by questing tree roots and tunnelling earthworms, whose underground engineering works are fundamental to soil health: improving drainage, drawing down oxygen and munching through organic matter to release vital nutrients. All this activity goes completely unseen but without it, there wouldn’t be much else to look at. Healthy soils are literally the foundations of healthy ecosystems, supporting all forms of life from the ground up. We couldn’t exist without it, so it’s only fitting that we named our planet Earth.

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