Lesson Notes By Weeks and Term - Senior Secondary School 2







  • Essential Geography for Senior Secondary Schools by O.A. Iwena






Irrigation agriculture is the type of agriculture which involves the artificial application of water to soil or land for farming purposes.  Irrigation is practiced 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 hence the popular saying “No Nile, No Egypt”.


Needs for Irrigation

(i)    Rainfall is low and unreliable in both Nile and Niger basins.

(ii)    Both areas are dry and arid.

(iii)    High rate of evaporation in the areas.


Factors that favour irrigation agriculture

(i)    Presence of rivers like River Nile and Niger.

(ii)    Presence of fertile alluvial soils.

(iii)    Incidence of low rainfall.

(iv)    Incidence of high rate of evaporation.

(v)    The need to control flooding.

(vi)    Resourcefulness of the people.

(vii)    Presence of large population.

(viii)    The quest to increase food production.



(i)    What is irrigation?

(ii)    Mention two reasons for irrigation Agriculture.

(iii)    Outline any four (4) factors that can favour irrigation agriculture.



(i)    It makes farmers to be less dependent on rainfall.

(ii)    It makes early planting possible.

(iii)    It enables farmers to cultivate one crop twice or thrice on the same piece  of land in a year.

(iv)    It increases the yield of crops.

(v)    It helps to reduce salt concentration in the soil.


Areas Covered by Irrigation

Irrigation agriculture is practiced in areas such as:

(a)    In the Nile Basin

    (i)    The Nile Delta        

(ii)    The Nile Valley       

  1. The Geizira plain or the managil extension
  2. The Lakeshores
  3. Aswan (Egypt)
  4. Khasimel Girba (Egypt)
  5. Sennar and Kenena regions of Sudan

(b)    In the Niger Basin

    (i)    Inland Niger Delta in Mali

    (ii)    The Niger Valley

  1. The Lakeshores e.g. Kainji Lake


Similarities between the Nile and Niger irrigation practices:

  1. Both irrigation practices depend on large dams.
  2. Both practices are perennial in nature.
  3. Both use carnal to channel their waters.
  4. Manual method is used in both areas.
  5. They both grow food crops e.g. cereal and vegetations /cash crops e.g. cotton & sugar.
  6. Both have small and large farms.
  7. Both could be owned by both government and individuals.


Reasons why irrigation is more important in the Nile Basin than in the Niger Basin

(1)    The Nile Basin (especially in Egypt) occupies more desert area than the Niger basin.

(2)    There are richer alluvial plains in the Nile than in the Niger Basin.

(3)    There is higher population in the Nile basin than in the Niger basin (This leads to greater demand for food production).

(4)    The Nile basin is used for more cash crop (e.g. cotton) production.



  1. Mention any two areas in the Nile basin where irrigation is practised.
  2. Mention any two similarities and two differences between irrigation practiced in both Nile and Niger basins.



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


Methods of Irrigation in use

The methods employed in both Nile and Niger Basins are the same.  They include:

(i)    Basin irrigation method:

This occurs 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 waters and soak the farmland, to form alluminium.  The method is ancient and almost obsolete because, it delays the farming process.

(ii)    Shaduf Irrigation:  This involves a hand operated lever lifting brickets of water from the river to the narrow channels running along ridges or patches of irrigation.

(iii)    Sakia Irrigation:  This is the use of animals such as oxen, donkeys, Buffalo or camels to bear containers around the body to deposit water to nearby farms.

(iv)    The use of pumps:  It involves the use of generators or pumping machines to get water out of the rivers or wells to farmland.  This sometimes is also referred to as “Sprinkler irrigation”.

(v)    Manual methods: This is the method where the local formers use buckets  and other water containers to fetch water from the river and pour them on farmland.

(vi)    Perennial method: This involves the use of dams, barrages and canals to store water and the water is released to farmlands during farming season.  It promotes the growth of crop al year 



Problems of Irrigation

Some of the problems associated with irrigation include:

(1)    Fluctuation in the volume of water in rivers can result to low yield of crops.

(2)    Irrigation equipment are expensive to purchase.

(3)    The construction of dams has led to the displacement of people from their original home lands.

(4)    Irrigation scheme requires high – technical know-how.

(5)    Most dams may collapse.

(6)    These is the problem of silting of dams.

(7)    Disaster can occur as a result of flooding.



  1. Mention any two methods of irrigation and briefly explain any one of them.
  2. Mention any four problems of irrigation.
  3. Name any two crops that are cultivated both in the Nile and Niger basins.




  • Mention any two methods of irrigation and briefly explain any one of them.


  1. Mention any four (4) problems of irrigation.
  2. Name any two crops that are cultivated both in the Nile and Niger basins.
  3. Outline three reasons why irrigation is more important in the Nile Basin them the Niger basin.
  4. Describe any two methods of irrigation practices in the Nile or Niger basin.



Essential Geography, O.A. Iwena Pages 493-495.



(1)    The Nile Basin depends on River _______ for irrigation? (a) Nile (b) Benue (c) Niger

(2)    Irrigation is practiced because ____ (a) Rainfall is in abundance    (b) Rainfall is scarce (c) the grass are scarce

(3)    One areas 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



(1)    What is irrigation?  Give three reasons why it is practiced in the Nile valley.

(2)    Outline five (5) factors that favour irrigation agriculture.

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