Fertilisers And Eutrophication

Question 1

What are the advantages of artificial fertilisers?

Answer 1

• ions immediately available to plant roots
• a known concentration of specific ions can be applied, so crop plants receive the optimum for fast growth rate

Question 2

What are the disadvantages of artificial fertilisers?

Answer 2

• highly soluble so leach into lakes causing eutrophication

Question 3

What are advantages of natural fertilisers?

Answer 3

• ions replaces slowly thus less leaching can take place
• wide range of ions present
• bulkier so improves soil structure
• cheaper

Question 4

What are disadvantages of natural fertilisers?

Answer 4

• can’t control concentration of ions present
• bulkier so more needs to be used to spread it out
• can contain weed seeds and fungal spores

Question 5

Describe the process of eutrophication.

Answer 5

1. Excess nitrates and phosphates are soluble so they enter the waterway due to leaching
2. Algae absorb increased levels of ions which causes an increased production of organic molecules cause the algal population to increase in number forming an algae bloom as ions are no longer a limiting factor for growth
3. Algal bloom can block light from reaching submerged plants, so they can’t photosynthesis and die
4. Dead matter increases, so more decomposition takes place and the saprobionts population increases
5. Saprobionts are aerobes so they use up the oxygen from the water for aerobic respiration
6. Depletion of oxygen causes death of other aerobic organisms as they can’t respire aerobically
7. Overtime, biodiversity decreases