NATURE OF SOIL

WHAT IS SOIL?

Soil is the accumulation of loosed, weathered materials that covers much of the land surface of the earth. Soil varies in depth, composition, age, colour and texture.

HOW SOIL IS FORMED

Soil is formed from the gradual break down of rocks called the bed rock or parent material. The process is known as weathering.

DEFINITION OF WEATHERING

Weathering is the gradual breakdown of rocks into smaller and smaller particles by agents such as water, temperature, wind, oxygen and roots of plants

TYPES OF WEATHERING

PHYSICAL WEATHERING: occurs when rock crack and crumble as a result of warming in the sun and rapid cooling after sunset.

CHEMICAL WEATHERING: occurs largely due to the action of atmospheric oxygen especially in the tropics.

BIOLOGICAL WEATHERING: involves the penetration of rocks by roots of plants.

COMPOSITION OR COMPONENTS OF SOIL

There are six main components of soil which are classified into two groups

ORGANIC COMPONENTS

• Humus
• living organisms

INORGANIC COMPONENTS

• Water
• Mineral salt
• Air
• Soil particles

Click on the link below to listen to the audio section of the lesson.............
https://drive.google.com/soil-JHS1-GMM4-7s/view?usp=drivesdk

EXERCISE 

1. State any five agents of weathering. 
2. Briefly explain why the penetration of plants roots through rocks is termed as biological weathering