Class 7 Science

Chapter 9: Soil

STAGE 0: Foundation / Basics

Soil is the top layer of the earth in which plants grow.

Soil is very important for agriculture and for life on earth.

Formation of Soil

Soil is formed by the breaking down of rocks into small particles.

This process is called weathering.

Weathering occurs due to:

• Wind
• Water
• Heat

Soil Profile

A soil profile shows different layers of soil.

Main layers of soil:

• Topsoil – upper layer, rich in humus
• Subsoil – middle layer, contains minerals
• Bedrock – hard rock at the bottom

Types of Soil

Three main types of soil:

• Sandy soil – large particles, drains water quickly
• Clayey soil – very small particles, holds water
• Loamy soil – mixture of sand, clay, and humus (best for plants)

Moisture and Water in Soil

Different soils hold different amounts of water.

• Sandy soil – least water
• Clayey soil – most water
• Loamy soil – balanced water

Importance of Soil

• Supports plant growth
• Provides minerals to plants
• Stores water
• Habitat for organisms

STAGE 2: NCERT Textbook Questions & Answers

Q1. What is soil?

Soil is the uppermost layer of earth where plants grow.

Q2. Name the three layers of soil.

Topsoil, Subsoil, Bedrock

Q3. Which soil is best for agriculture?

Loamy soil

STAGE 3: Exam-Oriented Questions

Fill in the blanks:

• Breaking of rocks into soil is called weathering.
• Topsoil is rich in humus.

Very Short Answer:

Name one type of soil.
Answer: Sandy soil

Quick Revision Points

• Soil supports life
• Soil is formed by weathering
• Loamy soil is best for crops
• Soil has three layers