Soil Structure and Its Importance
Imagine you’re walking in the forest or in a garden and you take a closer look at the ground. What you see as “soil” is actually a very special layer: the humus layer. It is found in the top 10 to 30 centimeters directly beneath the surface.
What is the humus layer?
The humus layer is the part of the soil where there is especially a lot of humus. Humus is everything that remains from plants and animals after their life: fallen leaves, small twigs, dead roots, and even animal remains. All of this is broken down by earthworms, beetles, woodlice, and countless tiny microorganisms like bacteria and fungi, turning it into a dark, crumbly mass.
What happens in this layer?
A lot of exciting things happen in the top 30 cm – it’s the “life beneath our feet”:
Decomposition: Everything that falls to the ground is eaten, shredded, and decomposed by small and tiny creatures. This takes a while, but in the end, it becomes humus.
Nutrient factory: In the humus layer, the nutrients that plants need are released. It’s like having a supermarket right under the roots – everything the plant needs is right there.
Water reservoir: The crumbly structure of humus holds water like a sponge. This is especially important when it doesn’t rain and plants get thirsty.
Habitat: In a handful of humus, there are more living beings than people on Earth. Earthworms dig tunnels and loosen the soil, so air and water can penetrate better. Other animals and microorganisms make sure everything works.
Why is this important?
The humus layer is the most important part of the soil for plants, animals, and us humans:
No humus, no plants: Plants get their food and water from the humus layer. Without it, they couldn’t grow.
No humus, no life: The many small creatures in the humus layer keep the soil healthy and prevent it from becoming a hard, lifeless mass.
No humus, no climate protection: Humus stores large amounts of carbon and thus helps to protect the climate.
Simply put
Imagine the soil is like a cake:
The top 30 cm are the tasty, loose layer with lots of raisins and nuts – that’s the humus layer. Below is the firmer part.
Just as a cake without raisins and nuts tastes boring, soil without humus is poor and infertile.
What happens during desertification and why the soil should remain permanently covered with plants
When soils become desertified
that is, they contain less and less humus and fewer and fewer plants grow – the following happens: The top, important soil layers dry out and are carried away by wind or rain. This is called erosion.
The soil loses its fertility.
It can no longer store water and offers hardly any living space for animals and plants. Where there were once green fields, bare, dry areas develop, similar to a desert – this is called desertification.
That’s why it’s so important to keep the soil permanently covered with plants and to protect it. A dense plant cover holds the soil together, prevents it from being blown or washed away, and ensures that new humus is formed. Only in this way does the soil remain fertile, can store water, and remains the basis for plants, animals, and us humans. Permanent greening and protection are therefore the best way to maintain healthy soils and a livable environment.
Author: Francesco del Orbe
