Agricultural Science

Grade 7• Week 5

• Lesson 1

• Topic: Soil Formation

• Objectives: At the end of the lesson you are expected

to:

1. Define soils

2. List the factors needed for soils to be formed

3. Identify rocks from the three main groups.

Soil FormationSoil forms when weathered parent material interacts with environment.

The Soil is the loose material on the earth’s surface, it is made up of:

• Mineral Materials

• Organic Materials

• Soil air

• Soil water

Origin of Soil:

• The development of soil is initiated by the

physical and chemical disintegration of rocks that are exposed to the earth's surface.

Origin Continue

• Rocks are continuously

breaking down and

decomposing to form

soil. Substances from

the rocks makes up the

mineral matter in the

soil. Rocks are formed

in three ways.

Igneous Rocks

• Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.

• Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses

Metamorphic Rocks

• Metamorphic rocks arise from the

transformation of existing rock types,

in a process called metamorphism,

which means "change in form". The

original rock is subjected to heat and

pressure, causing profound physical

or chemical change.

Sedimentary Rocks

• Sedimentary rocks are types of

rock that are formed by the

accumulation or deposition of

small particles and subsequent

cementation of mineral or organic

particles on the floor of oceans or

other bodies of water at the

Earth's surface

Reference

- https://youtu.be/amt-sPIbgK0

- https://www.slideshare.net/michaelnewbold9

80/an-introduction-to-soils-soil-formation-

and-terminology

- Agricultural Science for Secondary Schools in

Guyana: Book 1 by Edward O’D Williams et al

- Agriculture for CSEC: New Edition Revision

Course: by Sahadeo Ragoonanan

Review Activity

Review Activity