Class IV Science -Soil

Class IV Science

Soil

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Formation of SoilSoil is defined as the top layer of the

Earth ’s surface, which consists of sand, remains of dead plants and animals, and minerals with some amount of water and air in it.


Types of SoilThree types types of soil, depending on the size, feel, and colour of the soil particles

1. Gravel consists of tiny stones and does not hold water. 2. Sand is light and dry. Water passes easily through this

kind of soil as particles are rough.3. Clay particles are extremely fine. Water does not flow

freely through this soil.

Soil that consist s of clay, sand and humus is called loam.Loamy soil is good for growing plants.


Composition of soilSoil is made of Gravel, sand and clay particlesHumus (remains of dead plants and

animals)Water Air, minerals


Gravel

Soil Top soil

Uppermost layerContains sand, clay,

humus and waterGives nutrients to

plants.Subsoil

Middle layerContain broken pieces

of rock. Less humus

BedrockBottom layerLarge pieces of rockNot much water. www.reflectivelearn.com

Soil ErosionThe removal of the fertile topsoil by the

action of wind and water is called soil erosion.

Strong winds, heavy rainfall and cutting down of trees increase soil erosion.


Soil ConservationProtection of soil is known as soil

conservation.

Steps to conserve soil.More number of trees should be planted to replace

the ones that are cut down.Crop Rotation

Different types of crops should be grown on a farmland so that the soil gets time to recover its fertility.

Trees and bushes should be planted in open land to prevent wind to blow away topsoil.

Dams should be built across rivers to prevent floods.


Class IV Science -Soil

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Transcript of Class IV Science -Soil