Biol 4- fertilisers and nutrient cycles

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  • Created by: Elizabeth
  • Created on: 10-05-15 11:30
Why are fertilisers needed in an agricultural ecosystem?
To replace the lost ions which were taken up by crops. They also allow photosynthesis to be maintained.
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Why do nitrogen fertilisers reduce species diversity?
The nitrogen-rich soils favour the growth of grasses, nettles etc... so these weaker species get outcompeted.
2 of 10
How do fertilisers increase crop productivity?
They add essential nutrients needed for plant growth, increasing photosynthesis, and hence productivity.
3 of 10
Suggest a reason why, after a certain point, the addition of more fertiliser no longer improves the productivity of a crop.
Some other factor, e.g. light, is limiting photosynthesis. Only the limiting factor will increase photosynthesis and productivity.
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Which stage in the nitrogen cycle involves the production of ammonia from organic ammonium-containing compounds?
Ammonification
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Which stage in the nitrogen cycle involves the oxidation of ammonium ions in to nitrite ions and the oxidation of nitrite ions into nitrate ions?
Nitrification
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Which stage in the nitrogen cycle involves the process by which nitrogen gas is converted into nitrogen-containing compounds?
Nitrogen fixation
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Which stage in the nitrogen cycle involves the use of denitrifying bacteria converting soil nitrates into gaseous nitrogen?
Denitrification
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Why is does soil need to be kept well aerated?
To prevent the build up of denitrifying bacteria
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What are the two main human activities that have led to an increase in carbon dioxide levels in the atmosphere?
The combustion of fossil fuels and deforestation
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Other cards in this set

Card 2

Front

Why do nitrogen fertilisers reduce species diversity?

Back

The nitrogen-rich soils favour the growth of grasses, nettles etc... so these weaker species get outcompeted.

Card 3

Front

How do fertilisers increase crop productivity?

Back

Preview of the front of card 3

Card 4

Front

Suggest a reason why, after a certain point, the addition of more fertiliser no longer improves the productivity of a crop.

Back

Preview of the front of card 4

Card 5

Front

Which stage in the nitrogen cycle involves the production of ammonia from organic ammonium-containing compounds?

Back

Preview of the front of card 5
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