1. Nitrogen Cycle

2. Learning Intention: I can explain the stages of the nitrogen cycle Success Criteria; I can say why nitrogen is important I can take part in an activity to show how nitrogen travels in the earth I can name and describe the stages of the nitrogen cycle.

3. Nitrogen is present in plants in the form of PROTEIN. The plants may die or they may be eaten by animals. If they are eaten the animal GAINS the protein. This is one part of the nitrogen cycle. Nutrition Death Death and excretion

4. Bacteria and Fungi act as DECOMPOSERS and break down the dead organisms (plants and animals). This produces AMMONIA which is a compound that contains nitrogen. Plants cannot absorb ammonia, but NITRIFYING bacteria can change this into NITRITE. Other NITRIFYING bacteria change the nitrite into NITRATE which plants can then absorb. This is a second part of the nitrogen cycle. Ammonia Nitrite Nitrate

5. Nutrition Death and excretion Death Ammonia Nitrite Nitrate Absorbed by plant roots

6. A third part of the nitrogen cycle is the gaining of nitrogen from air. Special bacteria called NITROGEN FIXING bacteria live in the soil and take the nitrogen out of the air and change it into soil nitrates. NO 3

7. Denitrifying bacteria are present which can break down the nitrates. This releases the nitrogen back to into the air. This is a fourth part of the nitrogen cycle. Nitrogen fixing bacteria Denitrifying bacteria

8. The fifth part of the cycle involves a special group of bacteria called NITROGEN FIXING bacteria. These live in the root nodules of legumes (clover, beans, peas) and remove nitrogen from the air. But they give this nitrogen to the plant so it can make protein.

9. Lightning from the atmosphere can add nitrates to the soil. Loss of nitrogen Nitrogen can be lost from the soil by – the action of the denitrifying bacteria. –Leaching of nitrates into nearby river/water courses. –Harvesting of crops.

12. Task Collect a passport worksheet. At each reservoir roll the dice and use the key to work out where you will be going next. Fill in this information in your passport and stamp it to prove you have been at that station. Repeat until you passport if full.

13. Discuss –How many stops did you make? –Will your journey ever end? –Was everyone’s journey the same? Why not? –What would happen if a farmer used too much fertiliser (i.e. everyone started at fertiliser)? –What would happen if farmers increase livestock?

14. Task In your jotter write a paragraph to describe the path a nitrogen atom could take through the nitrogen cycle. Then complete the card sort.

15. This cycle only works if the nitrogen is replaced by the decomposing and rotting bodies of animals and plants. This does not happen in farming because the nitrogen in the plants/crops is not available to the soil. It has to be replaced by fertilisers.