Food and Resources KQ2 (Challenges of intensification)

Question 1

Waterlogging (Extensive irrigation)

Answer 1

• Too much water seeps into soil and causes it to become oversaturated
• Deprives roots of air and nutrients, killing crops

Question 2

Salinisation (Extensive irrigation)

Answer 2

• Water added to soil during irrigation evaporates directly
• Salt left behind

1) Occurs when there is no proper drainage of water
2) Ground water reaches topsoil, bringing up dissolved salts
3) Ground water evaporates, concentrating salts, kills crops
4) Salt makes ground hard, impermeable and cracked, unable to grow crops

Question 3

Salinisation example

Answer 3

Murray-Darling Basin, Australia
1) Extensive irrigation
2) Land development, clearance and deforestation
3) Low terrain, flat surface = high evaporation
4) Low rainfall + high temperatures

• Brings salt to surface, not allow it to wash off

Question 4

Eutrophication (Chemical usage)

Answer 4

1) Overuse of chemicals concentrate in soil
2) Chemicals seep into ground water, contaminating it
3) Chemical rich soil washed into streams
4) Chemicals become nutrients for algae to bloom
5) Eutrophication occurs when excess nutrients present in water = extensive algae bloom

Question 5

Impacts of Eutrophication

Answer 5

> Decreases oxygen, Dead water

1) Blocks out sunlight, prevents aquatic plants from photosynthesising

2) Algae takes O2 from water during photosynthesis

3) Plants and animals die from lack of O2

4) Decomposition depletes O2

• When O2 content cannot support life = dead water

Question 6

Eutrophication examples

Answer 6

e.g. USA
- High pesticide and herbicide usage
- Pollute rivers leading to eutrophication and dead water

-Ground water contaminated, leads to health risks
- 23% USA freshwater from ground water

Question 7

Measures to minimise eutrophication

Answer 7

1) Target surface-runoff management
- Measures to prevent nutrients from reaching water bodies
- Ineffective to treat waters after eutrophication has occurred

2) Raising awareness through public education
- Campaigns, school environmental education programmes, community outreach etc.

3) Monitoring pollution levels
- Detect, prevent and control eutrophication early
- Minimise environmental impact
- Requires efforts and co-operation between Govt, NGOS, and community