1. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
Farming and Desertification

2. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel

3. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• A Region in North Africa between 12 - 18˚N

4. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• A Region in North Africa between 12 - 18˚N
• Defined by climate as a transitional zone
between the Sahara to the north and more
equatorial areas to the south

5. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• A Region in North Africa between 12 - 18˚N
• Defined by climate as a transitional zone
between the Sahara to the north and more
equatorial areas to the south
• Drought is common

6. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel

7. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
Photograph copyright Ewan Robinson

8. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• For the last 5000 years the Sahel
region has experienced periods of
higher rainfall followed by dryer
periods roughly every 1000 years
Photograph copyright Ewan Robinson

9. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• For the last 5000 years the Sahel
region has experienced periods of
higher rainfall followed by dryer
periods roughly every 1000 years
• 1950’s to early 1970’s saw above
average rainfall
Photograph copyright Ewan Robinson

10. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel
• For the last 5000 years the Sahel
region has experienced periods of
higher rainfall followed by dryer
periods roughly every 1000 years
• 1950’s to early 1970’s saw above
average rainfall
• This was followed by drought for the Photograph copyright Ewan Robinson
last 30 years

11. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: population effects
Photograph copyright Ewan Robinson

12. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: population effects
• Population in the region is doubling
every 20 years
Photograph copyright Ewan Robinson

13. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: population effects
• Population in the region is doubling
every 20 years
• Population growth (3%) exceeds
growth in food production (2%)
Photograph copyright Ewan Robinson

14. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: population effects
• Population in the region is doubling
every 20 years
• Population growth (3%) exceeds
growth in food production (2%)
• Poverty is widespread - three of
the four poorest countries on Photograph copyright Ewan Robinson
Earth are in the region

15. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
Photograph copyright Ewan Robinson

16. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increasing population has led to
Photograph copyright Ewan Robinson

17. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increasing population has led to
• Overgrazing
Photograph copyright Ewan Robinson

18. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increasing population has led to
• Overgrazing
• Removal of trees for firewood
Photograph copyright Ewan Robinson

19. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increasing population has led to
• Overgrazing
• Removal of trees for firewood
• This is combined with poor farming
methods Photograph copyright Ewan Robinson

20. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood Increasing
population
More food
required
More Increased
livestock grazing
More fuel
Deforestation
needed for
for firewood
cooking
Removal of
vegetation
Soil exposed
to wind and
water
Top soil can
blow away
SOIL EROSION

21. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood Increasing
population
More food
required
• Leads to: More
livestock
Increased
grazing
More fuel
Deforestation
needed for
for firewood
cooking
Removal of
vegetation
Soil exposed
to wind and
water
Top soil can
blow away
SOIL EROSION

22. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood Increasing
population
More food
required
• Leads to: More
livestock
Increased
grazing
• Fewer plants to hold the soil More fuel
Deforestation
together
needed for
for firewood
cooking
Removal of
vegetation
Soil exposed
to wind and
water
Top soil can
blow away
SOIL EROSION

23. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood Increasing
population
More food
required
• Leads to: More
livestock
Increased
grazing
• Fewer plants to hold the soil More fuel
Deforestation
together
needed for
for firewood
cooking
• Soil surface exposed to wind
Removal of
vegetation
Soil exposed
to wind and
water
Top soil can
blow away
SOIL EROSION

24. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood Increasing
population
More food
required
• Leads to: More
livestock
Increased
grazing
• Fewer plants to hold the soil More fuel
Deforestation
together
needed for
for firewood
cooking
• Soil surface exposed to wind
Removal of
vegetation
Soil exposed
• Loose top soil blows away
to wind and
water
Top soil can
blow away
SOIL EROSION

25. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
20
Area Harvested (million ha)
10
1960 1970 1980 1990 2000 2010
Increase in area of land being harvested each year
(UNEP)

26. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
20
• Is grazing really the big problem? Area Harvested (million ha)
10
1960 1970 1980 1990 2000 2010
Increase in area of land being harvested each year
(UNEP)

27. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
20
Area Harvested (million ha)
10
1960 1970 1980 1990 2000 2010
Increase in area of land being harvested each year
(UNEP)

28. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increased population has led to a
20
need to expand agriculture for
Area Harvested (million ha)
both local use and export
10
1960 1970 1980 1990 2000 2010
Increase in area of land being harvested each year
(UNEP)

29. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increased population has led to a
20
need to expand agriculture for
Area Harvested (million ha)
both local use and export
• Increase the amount of poor 10
quality land used to grow crops
1960 1970 1980 1990 2000 2010
Increase in area of land being harvested each year
(UNEP)

30. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Grazing and firewood
• Increased population has led to a
20
need to expand agriculture for
Area Harvested (million ha)
both local use and export
• Increase the amount of poor 10
quality land used to grow crops
• Leads to increased soil 1960 1970 1980 1990 2000 2010
degradation in dry years Increase in area of land being harvested each year
(UNEP)

31. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Additional factors
Chad
Sudan
Central African
Republic
Conflict in the Dafur region
disrupts traditional nomadic
migration routes

32. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Additional factors
• Traditional agriculture was dependent on
nomadic herding
Chad
Sudan
Central African
Republic
Conflict in the Dafur region
disrupts traditional nomadic
migration routes

33. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Additional factors
• Traditional agriculture was dependent on
nomadic herding
• Post colonial borders cut across migration Chad
Sudan
paths
Central African
Republic
Conflict in the Dafur region
disrupts traditional nomadic
migration routes

34. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: Additional factors
• Traditional agriculture was dependent on
nomadic herding
• Post colonial borders cut across migration Chad
Sudan
paths
• Civil war and political unrest in the region Central African
Republic
leads to migration from rural areas to the
towns, intensifying grazing around urban
areas Conflict in the Dafur region
disrupts traditional nomadic
migration routes

35. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: The Results

36. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: The Results
• Smaller and smaller areas of grazing have
to support larger herds

37. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: The Results
• Smaller and smaller areas of grazing have
to support larger herds
• Cattle more susceptible to disease and
death

38. Topic 3.4: Soil System
Topic 3.5: Food Resources
Grazing and Soil degradation
The Story of the Sahel: The Results
• Smaller and smaller areas of grazing have
to support larger herds
• Cattle more susceptible to disease and
death
• Famine affects the growing population