SOIL-LAYERS OF SOIL

• What is soil?

• ​Soil is an important natural resource.

• ​Complex mixtures of minerals, water ,air and organic matter.( Humus)

• How it is formed?

• ​Soil is formed by breaking up of rocks.

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Our Previous Knowledge- What do we already know?

​1. Learn about the four main components of soil.

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​2. Identify organic and inorganic matter of soil.

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​3. Understand the formation and layers of soil.

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​1. Four main components of soil

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​2. Organic and Inorganic matter of Soil.

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​3. Formation of Soil

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​4. Layers of Soil

​Soil is made up of FOUR components:

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• In Organic ​Mineral matter (45%)

• ​Organic material (5%)

• ​Water (25%)

• ​Air (25%)

1. Inorganic Mineral Matter- ROCKS​

   Gravel

2. Stone

3. Sand

4. Clay

5. ​Silt

1. ​Organic Matter

   Humus​

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1. ​Feels sticky

2. ​Yellow/red in color

3. ​Poor drainage

4. ​SMALLEST particle size

5. Usually found in Plateaus

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1. ​Feels gritty

2. ​More of a gray or white color

3. ​

   Poor fertility (roots can't grip; not enough water or humus)

4. ​LARGEST particle size.

5. ​​Usually found in Deserts

1.      Silt

   ​Feels soft/smooth

2. ​Brownish/black in color

3. ​Larger than clay,

4. but smaller than sand

   It is very fertile

5. In India it is mostly found in northern plains.​

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1. ​It is an organic matter made up of waste from animals and dead leaves/plants which help us to make the soil fertile.​

2. ​We can add humus to inorganic mineral soil to make it more fertile.

1. O horizon-humus on the ground surface.

2. ​A horizon - Top Soil, rich in organic material.

3. ​B horizon -Subsoil, less organic material than topsoil, we can find deep root of plants in this zone.

4. C horizon- Parent material​ , slightly weathered rocks, no organic matter.

5. R horizon-Bedrock​ , Unweathered rock material.

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​READ THE QUIZ QUESTIONS CAREFULLY AND TICK THE CORRECT ANSWER.

​TIME- 30 SECONDS FOR EACH QUESTION

​DRAW A WELL LABELLED DIAGRAM OF LAYERS OF SOIL IN YOUR NOTEBOOK.