Page 187 - New Medley 3 Semester 2

 Topsoil: is is the uppermost

layer of soil. Plants and tiny
animals grow and live in this Ground level

layer. is layer of soil is loose Topsoil
and has air trapped in it.

 Subsoil: e layer below the Subsoil

topsoil is called the subsoil. is

layer is harder than the topsoil. Weathered

is layer of soil is closely packed parent material
with some pieces of rocks in it.
It has very little air in it. Bedrock

 Weathered parent material: is
layer of soil contains rock pieces Layers of soil

and particles that are di erent from the bedrock situated below.
 Bedrock: is is the lowermost layer of the soil. It contains solid rocks. ese

rocks are also called parent rocks.
Let’s now check out for the components of the topsoil.

• Hands-on Learning
Activity

Collect some soil from a garden or park and put it in a glass
jar. Pour some water into the jar. Stir the contents well with
a small wooden stick or twig. Allow it to stand for some time.

After some time, you can clearly see four different layers in Humus
the jar. Water

On the top, you will find twigs, dead leaves, etc., floating on Clay
water. These materials form the humus. Humus makes the soil
rich in nutrients which plants need to grow. Sand

 The next layer of muddy water contains very fine grains Gravel
called the clay.
 The next layer contains grains bigger than those of clay Layers of topsoil
and is called sand.
 The bottom layer contains small pieces of rocks and stones called gravel.

How Important is Soil

All crops are grown in soil. Plants need di erent types of soil to give the best
produce. For example, the rice crops are grown best in clay. Most vegetables and

wheat grow best in loam.

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