Classification Of Soil: Soil Formation, Meaning, Physical Properties & Types Of Soil

Meaning Of Soil:

If you look around your environment, you will see human beings, animals, treess and grassess. All of them are standing or moving on the soil.

Soil, therefore, is the top covering or upper part of the earth surface in which plants or trees grow.

Types Of Soil

There are three main types of soil: Sandy Soil (sand), Clayey Soil (clay) And Loamy Soil (Loam).

1. Sandy Soil: When rain falls, water runs on the ground and leaves some soil along its path. When the ground becomes dry, It is easy to collect the soil left with the hand. This soil type is called Sandy Soil.

2. Clayey Soil: Clay is a dark-brown, and it is not found everywhere. This type of soil can be used in moulding E.g Moulding pot, Cup, etc.

3. Loamy Soil: Loamy soil is a mixture of sand, clay and some dead plants and organic matter. This is the soil type in which plants mostly grow. You will see the following on Loam soil: decayed organic matter, dark soil and small soil particles. It is, therefore, very good for farming.

Soil Formation

Soil is formed in four main ways:

1. Through the breakdown of rocks into small particles by man, animals and plant roots.

2. By washing down the rock particles by water or wind.

3. Through heating of rocks by sunshine.

4. By the decay of plants and animals to form soil organic matter.

Have you ever seen a rock before? A rock is a big stone seen above the soil. Some farmers dry their crops on flat rocks. Some people build houses on rocks. Others sit on a rock to rest, while some others walk across it. All these acrivities help to break down rocks into small pieces.

Plants also help to break rocks into small particles as their roots crack rocks, especially trees which have very large roots. The breaking down of rocks into small pieces by man’s activities and plants helps to form soil.

Washing Down Of Rock Particles

The two major agents that cause this are water and wind. When wind blows on a rock and rain falls on it, they can break it down into particles that form soil.

Heating Of Rocks By Sunshine

This is the process by which the sunrays is heating the rocky hill. These hot rays heat up the rock, and it cracks in the process. The cracks form small particles. Then the heat from the sun helps to break the rock into small particles to form soil.

Decay Of Plants And Animals

Dead plants and animals decay to form soil. Decayed plants and animals form organic matter which helps to form soil.

Physical Properties Of Soil

Each soil type has some physical properties. The property of any soil type is what makes it different from others.

Sandy Soil

The soil is different from clay and loam in many ways:

i) Collect some dry sandy soil from a footpath with your left hand.

ii) Take a little of the soil with your right hand.

iii) Rub it in-between your fingers.

iv) How does it feel: Smooth or rough?

Sandy soil contains tiny stone particles. It is rough when rubbed between the fingers, and it runs freely through the fingers when dry. It is found mostly along footpaths, deserts and erosion areas It is lose and not that fertile.

Clayey Soil

Clayey soil is slippery and sticky when wet. When dry, clayey soil is hard, very smooth, feels like powder, and it cracks. Have you seen a cracked soil before? That is clay. Clay is a bit fertile.

i) Collect some wet clay and roll it between your palms. Describe what happens. Clay forms a ribbon-like shape when rolled wetween the palms.

ii) Allow the clay ribbon to dry.

iii) Grind the dry clay ribbon into powder.

iv) Rub the powder between your fingers.

v) Describe how it feels. Is it rough or smooth?

Loamy Soil

This property has properties that are different from sand and clay.

i) Take some soil from the school farm’s vegetable bed with a hand trowel.

ii) Rub a little of it between your fingers.

iii) Describe how it feels. Is it sticky or rough?

You will see that it is not as sticky as clay, and it is not as rough as sand. Loamy soil has a mixture of the properties of sand and clay. It is rich in humus. It is, therefore, fertile and the best for farming.

SUMMARY

In this article you have learnt that:

1. Soil is the top covering or the upper part of the earth surface in which plants or trees grow.

2. There are three main types of soil: Sand, Clay And Loam.

3, Soil hold, plants to the ground and provides them with food and water,

4. Loam supports growth of plants best.

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