Soil is the thin layer of grainy substance covering the earth's surface, formed by weathering of rocks and decomposition of organic matter over long periods. It takes over 1000 years to form an inch of soil. The study of soil is called pedology. The five main factors that influence soil formation are climate, topography, plants and animals, parent rocks, and time. Soil is essential for plant growth and agriculture, protects from erosion, holds water, and supports a large biological community.

1. WELCOME
CHAPTER 3 – IN SEARCH OF EARTH'S SECRETS
PRESENTED BY
SHARAN R
Emmanuel college of B.Ed. Training

2. What is Soil ?
• The thin layer of grainy substance covering the surface of the
earth is called soil.
• Soil is made up of organic matter, minerals and weathered
rocks found on the earth.

3. Soil formed…..
• The soil is formed by prolonged processes like weathering of rocks
and decomposition of organic matter.
• The right mix of minerals and organic matter make the soil fertile.
• It is estimated that more than a 1000 years is required for the
formation of an inch-thick layer of soil.

4. Study of Soil…..
• Pedology is the branch of science that deals with soil.
• The scientists associated with this branch are called Pedologists.

5. Factors influencing soil formation
1. CLIMATE
2. TOPOGRAPHY ( LANDFORMS )
3. PLANTS AND ANIMALS
4. PARENT ROCKS
5. TIME

6. 1. CLIMATE
• Temperature, Rainfall
influence rate of
weathering and humus.

7. 2. TOPOGRAPHY
Altitude and slope,
determine
accumulation of soil.

8. 3. PLANTS AND ANIMALS
•Plants, animals and Micro-organism affect the rate
of humus formation

9. 4. PARENT ROCKS
Determines colour, texture,
chemical properties of
mineral, content,
permeability

10. 5. TIME
• Determines thickness of soil profile.

11. SOIL SUPPORTS LIFE……
• Soil is one of the important factors that makes life on the earth
possible.
• The green plants absorb nutrients from the soil
• Then, prepare food with the help of sunlight.
• Humans and other animals consume these plants.
• When plants and animals die.
• then it return to the soil.

12. • Essential for plants growth.
• Importance to agriculture
• Protect plants from erosion
• Provide air for gaseous exchange between roots and
atmosphere.
• Hold water moisture in land
• For construction purposes
• For making Pottery
• Support large biological community.
IMPORTANCE OF SOIL

13. WORLD SOIL DAY : 5TH DECEMBER
5TH DECEMBER, 2018 THEME :
"Be the Solution to Soil Pollution"

14. QUESTIONS
1. What is Soil ?
2. Study of Soil is known as ?
3. How many years will took to form a thin layer soil ?
4. What are five factors influence in the soil formation ?
5. Give some uses of soil ?