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Soil - Soil Erosion and Conservation methods

Grade 5ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Soil is the uppermost layer of the Earth's crust, essential for plant growth and life. It takes approximately 500500 to 10001000 years to form just 11 inch of topsoil.

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Soil Erosion: The process of carrying away or washing away of the fertile topsoil by natural agents like wind and running H2OH_2O.

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Agents of Erosion: Running water (washes away soil in floods), Wind (blows away loose soil in deserts), and Human Activities like deforestation and overgrazing.

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Soil Conservation: The protection of soil against erosion to maintain its fertility. It involves methods that reduce the speed of wind and H2OH_2O.

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Afforestation: Planting trees on a large scale. Roots of trees act as binders that hold soil particles together.

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Terrace Farming: Also known as step farming, it is practiced on hilly slopes by cutting steps to reduce the flow of H2OH_2O.

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Shelterbelts: Planting rows of trees or shrubs along the edges of farmlands to reduce the speed of the wind.

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Embankments: Building wallswalls or bundsbunds along river banks to prevent the river from overflowing and washing away soil.

📐Formulae

Soil Composition≈45% Minerals+25% Air+25% Water+5% Organic Matter\text{Soil Composition} \approx 45\% \text{ Minerals} + 25\% \text{ Air} + 25\% \text{ Water} + 5\% \text{ Organic Matter}

Sand (Silica)=SiO2\text{Sand (Silica)} = SiO_2

Limestone (Calcium Carbonate)=CaCO3\text{Limestone (Calcium Carbonate)} = CaCO_3

💡Examples

Problem 1:

A farmer in a hilly region observes that heavy rainfall washes away the topsoil of his farm, making it difficult for crops to grow. Suggest a conservation method and explain its scientific benefit.

Solution:

The farmer should adopt Terrace Farming.

Explanation:

In hilly areas, H2OH_2O flows down the slopes at high speed, carrying soil with it. By cutting 'steps' or terraces, the speed of the H2OH_2O is reduced. As the water slows down, the soil eroded from one step is deposited on the next step, preventing total loss of fertile topsoiltopsoil.

Problem 2:

In a dry, flat region with high wind speeds, a farmer finds his topsoiltopsoil blowing away. What should he plant around his field to prevent this?

Solution:

The farmer should plant Shelterbelts.

Explanation:

Shelterbelts are rows of trees planted at short intervals. These trees act as a physical barrier that breaks the force of the wind, thereby preventing the wind from lifting and carrying away the dry, loose soilsoil particles.