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Shifting cultivation Oldest form of agriculture in Africa Slash and burn Four steps 1. cut primary forest.

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Presentation on theme: "Shifting cultivation Oldest form of agriculture in Africa Slash and burn Four steps 1. cut primary forest."— Presentation transcript:

1 Shifting cultivation Oldest form of agriculture in Africa Slash and burn Four steps 1. cut primary forest

2 2. Burn remaining vegetation: ash acts like a fertilizer 3. Plant for 2 to 3 consecutive years 4. Fallow for about 20 years

3 Three stages of S/B and Fallow

4 Typical Village

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6 Old self-sufficient patterns Rarely exist Creation of markets People aim for surplus Trade with surrounding villages

7 Current Practice: Rotational Bush Fallow 2 to 10 years Requires supplementary methods such as fertilizers or manure Not all farmers have these

8 More affluent farmers have cattle for plowing and manure

9 Intercropping Old pattern Spreads risk Discouraged by “modern” scientists Can help prevent erosion

10 Desertification Land severely degraded Brings desert- like conditions An underlying cause of declining food production

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12 Sahel in the 1970s and 1990s Millions of people and cattle died

13 Areas looks like this and causes many people to flee (produces refugees)

14 African droughts are common But are accelerated by – population increases, both human and animal –cutting trees

15 Final Stages of Desertification

16 Forests (tree cover) prevent erosion

17 Thin layer of soils over rock Hard to bring back the land into production

18 Use of plow and monocropping promotes desertification

19 Cash crops like cotton promote desertification

20 Increased need for fuelwood promotes desertification Blaming the victim More forests cut by loggers

21 Major problems Desertification Deforestation Soil Erosion

22 Desertification deforestation irrigation increased population of humans and animals drought conditions accelerate

23 Deforestation fuelwood construction shifting cultivation commercial logging

24 Soil Erosion Deforestation Monocropping; cash crops Use of plow Soils lose fertility

25 Other environmental issues Wildlife Toxic waste dumping

26 What can be done? Afforestation (tree planting programs) –especially for women as they are responsible for fuelwood Better design of irrigation –water from rivers –build dams (old approach)

27 Better agricultural policies and assistance to rural populations Allow intercropping Natural fertilizers Cull livestock Urban jobs

28 Irrigation could be a solution but Salinization because of poor drainage of the soils

29 Nile is famous example of salinization

30 salt buildup Inhibits plant growth and yields

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