Irrigation Agriculture in Nile Basin and the Niger Basin – SS2 Geography Lesson Note (Third Term)

Irrigation agriculture is the type of agriculture which involves the artificial application of water to soil or land for farming purposes. Irrigation is practised in areas where rainfall is insufficient, like Egypt and Sudan in the Nile Basin (using River Nile) and Mali and Northern Nigeria in the Niger Basin (using River Niger).

Irrigation makes farming possible throughout the year. River Nile is so important to Egypt that there is a popular saying, “No Nile, No Egypt”.

Behavioural objectives

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

• define irrigation agriculture;
• state the needs for irrigation and the factors that favour it in the Nile and Niger basins;
• list the areas and crops covered by irrigation in the two basins;
• describe the methods of irrigation in use;
• state the importance and problems of irrigation.

What are the needs for irrigation?

1. Rainfall is low and unreliable in both the Nile and Niger basins.
2. Both areas are dry.
3. The rate of evaporation in the areas is high.

What factors favour irrigation agriculture?

1. Presence of rivers like River Nile and River Niger.
2. Presence of fertile alluvial soils.
3. Low rainfall.
4. High rate of evaporation.
5. The need to control flooding.
6. Resourcefulness of the people.
7. Presence of a large population.
8. The quest to increase food production.

Why is irrigation important?

1. It makes farmers less dependent on rainfall.
2. It makes early planting possible.
3. It enables farmers to cultivate one crop twice or thrice on the same piece of land in a year.
4. It increases the yield of crops.
5. It helps to reduce salt concentration in the soil.

Where is irrigation agriculture practised?

In the Nile Basin

• The Nile Delta
• The Nile Valley
• The Gezira Plain and the Managil Extension
• The lakeshores
• Aswan (Egypt)
• Khashm el Girba (Sudan)
• Sennar and Kenana regions of Sudan

In the Niger Basin

• Inland Niger Delta in Mali
• The Niger Valley
• The lakeshores, e.g. Kainji Lake

What are the similarities between Nile and Niger irrigation practices?

1. Both depend on large dams.
2. Both practices are perennial.
3. Both use canals to channel their waters.
4. The manual method is used in both areas.
5. Both grow food crops, e.g. cereals and vegetables, and cash crops, e.g. cotton and sugar cane.
6. Both have small and large farms.
7. Farms in both areas may be owned by the government or by individuals.

Why is irrigation more important in the Nile Basin than in the Niger Basin?

1. The Nile Basin (especially in Egypt) occupies more desert areas than the Niger Basin.
2. There are richer alluvial plains in the Nile Basin than in the Niger Basin.
3. The population of the Nile Basin is higher than that of the Niger Basin, which leads to a greater demand for food.
4. The Nile Basin is used for more cash crop production (e.g. cotton).

Which crops are cultivated under irrigation?

1. In the Nile Basin: cotton, sugar cane, millet, wheat, maize and rice.
2. In the Niger Basin: groundnut, maize, guinea-corn, onions, sugar cane and rice.

What methods of irrigation are in use?

The methods used in the Nile and Niger basins are the same. They include:

1. Basin irrigation: This happens during the annual flooding of rivers, which occurs between August and October as a result of the heavy summer rain. As the river overflows its banks, basins are created on the farmland to trap the water and soak the land, and alluvium is deposited. The method is ancient and almost obsolete because it delays the farming process.
2. Shaduf irrigation: A hand-operated lever lifts buckets of water from the river to narrow channels running along ridges or to patches of irrigated land.
3. Sakia irrigation: Animals such as oxen, donkeys, buffalo or camels carry containers of water to deposit it on nearby farms.
4. Use of pumps: Generators or pumping machines draw water out of rivers or wells to the farmland. This is sometimes referred to as sprinkler irrigation.
5. Manual methods: Local farmers use buckets and other water containers to fetch water from the river and pour it onto the farmland.
6. Perennial method: Dams, barrages and canals store water, and the water is released to farmlands during the farming season. It promotes the growth of crops all year round.

What are the problems of irrigation?

1. Fluctuation in the volume of water in rivers can result in low crop yield.
2. Irrigation equipment is expensive to purchase.
3. The construction of dams has led to the displacement of people from their original homelands.
4. Irrigation schemes require high technical know-how.
5. Dams may collapse.
6. Dams become silted.
7. Flooding can cause disaster.

Evaluation

1. Define irrigation agriculture.
2. State three needs for irrigation in the Nile and Niger basins.
3. List four methods of irrigation.
4. Give two reasons why irrigation is more important in the Nile Basin than in the Niger Basin.
5. State three problems of irrigation.

Assignment

1. The Nile Basin depends on the River _______ for irrigation. (a) Nile (b) Benue (c) Niger
2. Irrigation is practised because ____ (a) rainfall is in abundance (b) rainfall is scarce (c) grass is scarce
3. One area of irrigation in the Niger Basin is ____ (a) Mali (b) Egypt (c) Sudan
4. Irrigation makes food ____ (a) scarce (b) plenty (c) costly
5. Irrigation in Egypt and Sudan is popular because the countries are located in ____ (a) the forest regions (b) the Mediterranean regions (c) the desert regions