Human influence on the nitrogen cycle
This presentation is the property of its rightful owner.
Sponsored Links
1 / 10

Human influence on the nitrogen cycle PowerPoint PPT Presentation


  • 112 Views
  • Uploaded on
  • Presentation posted in: General

Human influence on the nitrogen cycle. T he nitrogen cycle Re-cap The last lesson was about the nitrogen cycle. What do organisms use nitrogen for?. How do animals get their nitrogen?. How do plants get their nitrogen?. Which types of decomposers are responsible for

Download Presentation

Human influence on the nitrogen cycle

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Human influence on the nitrogen cycle

Human influence on the nitrogen cycle

Energy in Ecosystems


Human influence on the nitrogen cycle

The nitrogen cycle

Re-cap

The last lesson was about the nitrogen cycle.

  • What do organisms use nitrogen for?

  • How do animals get their nitrogen?

  • How do plants get their nitrogen?

  • Which types of decomposers are responsible for

  • releasing nitrogen from dead organisms?

  • Which type of organisms convert ammonium

  • compound to nitrates?

Energy in Ecosystems


Human influence on the nitrogen cycle

Today we are learning about:

How humans can influence the nitrogen cycle

  • Success criteria

  • Be able to explain how and why humans influence

  • the levels of nitrogen in the cycle

Energy in Ecosystems


Human influence on the nitrogen cycle

Human influence on the nitrogen cycle

  • Humans influence the nitrogen cycle particularly in

  • relation to their farming activities.

  • Harvesting crops removes nitrogen locked up in

  • the crops that could have gone back into the soil.

  • How do farmers put the nitrogen back into the soil?

Energy in Ecosystems


Human influence on the nitrogen cycle

Did you get all of these?

  • Adding fertiliser

  • Adding manure

  • Adding compost

  • Growing crops like clover

  • Fertilisers are (man made) chemicals used to add a

  • variety of essential minerals including nitrogen (N),

  • phosphorus (P) and potassium (K) to the soil.

  • This why fertiliser bags are labelled N:P:K

Energy in Ecosystems


Human influence on the nitrogen cycle

The N:P:K balance can be altered to provide to

provide the correct mineral balance for the crops

being grown.

  • For root crops a high proportion of P

  • For leaf crops a high proportion of N

  • For flower and fruit crops a high proportion of K

Energy in Ecosystems


Human influence on the nitrogen cycle

Manure or compost which are natural fertilisers

can also be added to the soil by farmers which

adds nitrates as it decomposes.

  • Growing crops like clover (legumes) will return

  • nitrogen because they have root nodules with

  • bacteria that fix nitrogen into nitrates.

  • The clover is ploughed back in to the soil before a

  • new crop is planted.

  • Increasing the nitrates (and other minerals) will

  • increase the yield in the crops being grown.

Energy in Ecosystems


Human influence on the nitrogen cycle

Excessive use of fertilisers

  • Farmers can apply more fertilisers or manure than

  • the crops can use.

  • These excess nitrates can end up in fresh water like

  • rivers, reservoirs and lochs as run-off when it rains.

  • This can cause an increase in the growth of algae

  • in the water (algal blooms) which can block out light.

Energy in Ecosystems


Human influence on the nitrogen cycle

Excessive use of fertilisers

  • As the algae die they sink to the bottom and decay.

  • This decay uses up a lot of oxygen that is in the water.

  • This lowers the oxygen level and increases the deaths

  • of other organisms in the water like invertebrates

  • and fish.

  • This means the water will support less life so it

  • reduces the biodiversity.

Energy in Ecosystems


Human influence on the nitrogen cycle

Human influence on the nitrogen cycle

  • Before you leave you need to write down on

  • your exit ticket answers to the following.

  • 3 ways humans add nitrogen to the cycle

  • What can happen to the excess nitrogen added?

  • Why this could be negative for the environment?

  • Let the teacher see your exit ticket.

Energy in Ecosystems


  • Login