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Soil is extremely useful. Plants to grow in it and it is home to millions of insects, termites and worms.
Soil takes many years to form and is made up of a mixture of different things. The four main ingredients are:
1) Pieces of finely ground rock.
2) Humus (humus is made up of little bits of decayed leaves and tiny pieces of rotting wood, seeds and decayed plants and animals)
3) Water
4) Air
Soil is made up of different layers.
THE TOP LAYER is the richest in NUTRIENTS as it contains the most HUMUS. This soil is usually dark in colour.
SECOND LAYER is called SUB SOIL - and contains very little HUMUS.
Both top soil and subsoil are made up of rock that has been ground down over many years by rain, running water, frost, heat and wind.
Soil is different in different parts of the country and the world.
This is because the rocks and organic matter that make up the soil are different in different parts of the world.
The different types of rock that are ground down make different types of soil.
SANDY SOIL, this is light and dry and because it contains large amounts of air, water drains through easily.
CLAY SOIL, this is very heavy and quite sticky when wet. Because it is so stick and heavy water does not drain though it easily.
GRAVELLY SOIL, is full of tiny stones and because of this water drains away quickly.
