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Soil is the thin layer of loose
material on the land. Soil
contains minerals, air, water,
and decaying organic matter.
Soil
What is a scientist who studies soil called?
Planet Earth
Layers in soil
Soil builds up in
layers over many
years. Plant roots
grow in the topsoil,
which is generally
the richest in plant
food. The lower
layers are rocky.
Plant roots do
not reach this far
down in the soil.
Healthy humus
Humus is a dark,
rich substance
made up of rotting
plants and animals
(called “organic
matter”). It contains
lots of nutrients,
which plants need
to grow.
Life underground
Soil is home to thousands
of animals, including
slugs, ants, beetles,
and spiders. Larger
animals that spend time
underground, such as
moles, mix up humus and
minerals as they burrow
through the soil.
Bedrock
Humus
Subsoil
Topsoil
Regolith
