5.4 Nutrient Cycles

Question 1

Denitrification

Answer 1

Reduces nitrates to nitrogen gas

Pseudomonas Bacteria

Question 2

Nitrogen Fixation

Answer 2

From N2 to ammonia

By symbiotic Rhizobium in legumes

Question 3

Decomposition

Answer 3

Microorganisms of decay

Break molecules into ammonia

Question 4

Ammonification

Answer 4

Excrement turned into ammonium ions by Saprobionts

Question 5

Nitrification

Answer 5

Plants can take up nitrates
Ammonium compounds are oxidised into nitrates by Nitrosomonas and Nitrobacter.

This requires oxygen

Question 6

Fertilisers

Answer 6

Introduce N P K into soil
Increase crop yield
Develop plants earlier

Question 7

Organic Fertiliser pro and Cons

Answer 7

Pro: 
Plants develop earlier
Grow taller
Great lead area
Better soil

Cons:
Fertiliser wash off
Eutrophication 
Sewerage sludge
Weeds grow
Fungal spores

Question 8

Artificial fertiliser pro and cons

Answer 8

Pro:
plants develop earlier
Grow taller
Greater leaf area
Less required to be used 

Cons:
Fertiliser wash off
Eutrophication 
Heavy metals
Organophosphate poisoning
Acidification of soil
Breakdown symbiotic bacteria

Question 9

Phosphorus Cycle

Answer 9

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