Sustainable Farming
How can we manipulate an ecosystem without destroying it ?
Starter: Why are the following problems for maintaining a closed loop ecosystem?
1) Harvesting crops.2) Growing fields of 1 species of crop.3) Grazing animals.
• describe how human activity can unbalance natural ecosystems
• name and outline examples of unsustainable activities
• propose solutions that allow natural resources to be used sustainably
Sustainable Fishing
Problem: Fish stocks of some species are falling.
Task: make a list of ways we can try to make sure we do not over fish. What might are the potential problems with enforcing your ideas.
Idea: have fishing quotas / bans Problems.1) Boats overfish and dump the dead fish back into the sea to
get on quota.
2) Boats move to unprotected waters.
3) Politicians want to preserve jobs so allow more fishing than recommended.
Idea: ban fishing for certain fish Problems.
Idea: have fish farms Problems: not sustainable (linear system).
Intensive Agriculture
California grows 80% of the worlds Almonds. It is a linear system that removes the almonds meaning Farmers have to fertilise the soil.
Eutrophication
eutrophication
• http://www.youtube.com/watch?v=h-zncNp-X-E
• http://www.youtube.com/watch?v=UGqZsSuG7ao
Complete the cut and stick exercise. Use it to help you answer the following questions.
1) Describe in detail how fertilisers from a field can kill the life in a pond. (6 marks)
2) Which chemical in the fertilisers is the main contributor to eutrophication. Why?
3) How could farmers fertilise their soils without the use of chemicals?
Desertification
Think – Pair- Share
Describe what you think desertification is.
Task
• Complete the card sort to work out the order of events in desertification.
• Use this to answer the following question.
Explain the process of desertification outlining the possible causes and the impacts on the ecosystem.
Increase in land
conflicts
increased poverty
exposure & erosion of soil by
wind & rain
Possible Effects Possible Solutions
sand dunes forming on
valuable land
climate change
vehicle tracks
death of livestock
soil compaction
reduced moisture in the atmosphere (less
transpiration)
reduced biodiversity climate
change (reduced rainfall) evaporation
followed by salinisation
increased poverty
rise in human population
burning vegetation
education & consultation with local populations
trampling of vegetation by large animal
herds
tree planting to make wind breaks &
provide fuel wood
grazing control or rotational
grazing
cutting trees for fuel wood
Improved livestock
marketing
loss of vegetation
overgrazing
Possible Causes
digging moisture traps
(hollows)
national & international political discussions &
negotiations
planting legumes to
increase soil fertility
terracing of slopes to stop
run off
exposure & erosion of soil by
wind & rain
Increase in tribal
conflicts
Task
• Describe the possible solutions for desertification and what their limitations might be.
Plenary
Eutrophication or Desertification?
Eutrophication Desertification
Both
Plenary
Caused by excess nutrients
Eutrophication Desertification
Both
Plenary
Can be caused by farming/cultivation
Eutrophication Desertification
Both
Plenary
Produces an area with low biodiversity
Eutrophication Desertification
Both
Plenary
Produces an area with low biodiversity
Eutrophication Desertification
Both
Plenary
Can be prevented by sustainable farming
Eutrophication Desertification
Both
