Small scale irrigation. Image credit

ZIMSEC O Level Geography Notes:Agriculture:Farming types in Africa:Irrigation Farming

  • This is the artificial application of water on land in order to grow crops when prevailing climatic and weather conditions cannot sustain such crop growth.
  • This expensive farming system is carried out in order to:
    1. Increase food production for the ever expanding human population.
    2. Produce crops throughout the year.
    3. Deal with problems of moisture-stress on crops during inter-seasonal and intra-seasonal droughts.
    4. Bring marginal lands into active production.
    5. Generate more employment.
    6. Produce industrial raw materials and save foreign currency on imports of these.
    7. Raise living standards of people employed.
    8. Improve the national economy.
    9. Harness and utilize water that might have been lost through run-off.

Environmental conditions promoting irrigation farming

  • Whereas this type of farming may occur anywhere, where there is water and land, ideally some conditions must prevail for optimum irrigation to be undertaken.
  • There should be existence of vast stretches of gently sloping land which will enable easier laying down of irrigation pipes, digging of canals, creation of larger fields or even permitting gravity flow of water onto the fields thus reducing pumping expenses.
  • Clayey sub-soils reduce water loss through seepage and canal need not be lined with concrete, reducing running expanses.
  • Hot, dry environment (semi-arid to arid areas) conditions provide the heat required for fast plant growth. The dryness reduces the incidence of crop diseases and pests.
  • Hot, dry conditions also lead to the growth of bushy or grassy vegetation which is not difficult to clear. Overally, hot, dry areas have low population densities and so there is not much displacement of people.
  • Presence of large rivers and acquifers ensure adequate supply of water needed for irrigation. Dams may be built on rivers to store water or the water may be drawn from the rivers if they have the perennial flow straight to the fields.

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