Vegetation – SS2 Geography Lesson Note (First Term)

The vegetation of Nigeria falls into three major zones: forest, savanna and montane. Soils in Nigeria fall into four zones: laterite, sandy, forest and alluvial. Each soil zone is found in particular places in the country. This note describes each zone and where it is found.

Behavioural objectives

By the end of the lesson, students should be able to:

• name the three major vegetation zones of Nigeria and their subdivisions;
• define soil;
• list the four major soil zones of Nigeria;
• describe each soil zone and state where it is found;
• link each soil zone to its vegetation or cause of formation.

What are the vegetation zones of Nigeria?

The vegetation of Nigeria can be grouped into three major zones:

1. Forest zone

This zone contains mainly trees. It is subdivided into:

• Mangrove swamp forest: salt and freshwater swamp
• Rainforest

2. Savanna zone

This zone is made up mainly of grasses. It is further subdivided into three parts:

• Guinea savanna
• Sudan savanna
• Sahel savanna

3. Montane vegetation

This is mainly found in highland areas such as Jos and Adamawa.

What is soil?

Soil is the thin uppermost layer of the earth’s crust on which plants grow.

What are the soil zones of Nigeria?

Soils in Nigeria can be grouped into four major zones:

1. Zone of laterite soil
2. Zone of sandy soil
3. Zone of forest soil
4. Zone of alluvial soil

1. Zone of laterite soil

These soils are found in the interior of Nigeria, in places such as Jos, Makurdi, Minna, Enugu and Abuja. They are associated with the Guinea savanna and are heavily leached by rainfall. They are usually reddish because of the iron they contain.

2. Zone of sandy soil

These soils are found in the extreme northern part of Nigeria, in places like Sokoto, Katsina, Kano, Damaturu and Maiduguri. They are associated with the Sudan and Sahel savanna. They form because of dryness and the deposition of sand by wind.

3. Zone of forest soil

This soil is found in the southern belt and southwestern part of Nigeria, in places like Ibadan, Akure, Benin City, Ogun, Anambra and Imo. It is associated with forest vegetation and is rich in humus from fallen and decayed leaves.

4. Zone of alluvial soil

This soil is found around Ilorin, Lokoja and the Niger Delta areas of Warri, Port Harcourt and Calabar. It is associated with fine alluvial deposits at the lower course of a river.

Evaluation

1. Name the three major vegetation zones of Nigeria.
2. List the three subdivisions of the savanna zone.
3. Define soil.
4. Why is laterite soil usually reddish?
5. Name two places where sandy soil is found and the vegetation it is associated with.

Assignment

1. The best soil for planting is … soil. (a) sandy (b) clayey (c) loamy
2. Sandy soil is more dominant in which of the following areas? (a) Warri (b) Lagos (c) Kano
3. Laterite soil is more dominant in which of the following areas? (a) Makurdi (b) Lagos (c) Kano
4. Savanna vegetation is characterised by (a) trees (b) grasses (c) raffia palms
5. Soil porosity is highest in … soil. (a) sandy (b) loamy (c) clayey