ZIMSEC O Level Geography Notes:Agriculture:Farming types in Africa: Subsistence farming:Shifting Cultivation
Areas where practised in Africa
- Central DRC,
- Miombo Woodlands of Tanzania,
- The Chitemene system by the Bemba and the Ushi in north-east Zambia,
- The Chiinge system in the Chipinge area of Zimbabwe and
- Central Guinea.
- Shifting cultivation as a system depends on the availability of vacant land that is forested for its survival.
- The vacant land is required by the farmers to undertake their activities there as absence of people or a low population density ensure availability of land to shift to.
- Forests are necessary because it is the trees that will be cut and burnt to provide the ash needed as fertilizer.
- A clan comes into a forested area and establish their village at the centre.
- Plots are marked up in the forest.
- The families clear the land using axes.
- The men climb up the tall trees to cut off the branches while women and children collect the cut branches in the centre of the field where they are arranged in a circular pattern.
- As the rainy season approaches, the dry branches are burnt to produce ash which is spread on the plot to be ploughed.
- The burning must be timed perfectly.
- Too early burning may mean the ashes will be blown away by the wind while a late burning after the start of the rains will result in some branches not burning completely thereby reducing the amount of ash produced.
- The burning loosens the soils so that at times ploughing is not necessary.
- Digging sticks are used to drill holes into the ground in which seeds are dropped and buried.
- Crops of smaller seeds are sown by the broadcast method.
- Broadcast seeding is a method of seeding that involves scattering seed, by hand or mechanically, over a relatively large area.
- Little weeding is done especially in the first two years as the weeds would have been destroyed by fire.
- As the crops grow to maturity, they need to be protected against birds and wild animals.
- Once ripe the crops are harvested using knives, hoes and by hand picking.
- These are stored in simple granaries.
- After about five years, as yields become lower, the farmer start to clear yet another piece of land.
- Eventually the whole village shifts to a new site when cultivable plots become farther from the homes at the old village.
- The forest regenerates and after 30-40 years, the farmers will come back to former sites.
- Slash and burn produces several benefits such as converting biomass or decayed plant matter into ashes and soils rich in nutrients.
- It can also prevent the infestation of pests and weeds.
- Requires little capital investment
- Land is given time to recuperate and get back it’s nutrients
- It is organic as no chemicals are used
- Soil borne diseases are controlled/destroyed during the burning process
- It is unsustainable
- Destroys the environment
- There is risk of forest fires which may cause further and unintended environmental damage
- Destroys animal habitats
- Cannot keep up with demand
- Is not possible with large populations and high population density
- Deforestation results in accelerated environmental degration
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