1. Nitrogen Cycle and Eutrophication

2. Nitrogen Cycle
Protein is the main ingredient for all cells, and Nitrogen is needed to make it.
Nitrogen gas cannot be used so it must be taken up by plant roots in the form of NITRATES
Copy the picture on p.174 (simple version!)
Write about the 3 types of microbe which add the N: Decay microbes, Nitrifying bacteria, and Nitrogen fixing bacteria.

4. Homework Questions
1. In a CROP ROTATION (see farming sheet) why are LEGUMES grown, then ploughed in? 2. Manure spreading is done in autumn a long time before the seeds are planted. Why? 3. Chemical fertilisers are added as the crop is growing. Why is this different to manure? 4What can happen if too much chemical fertiliser is added?

5. Eutrophication Read the middle section of P.178 Beckett
What is eutrophication?
Draw a flow diagram or cartoon to show the sequence of events from fertiliser enrichment to the death of fish in a pond

6. Microbes in the NitrogenCycle
Decay microbes – eg f________ and b______
Turn o______ m_______ to am_______.
Nitrifying bacteria turn am_____ to n______ for plants to take up.
Nitrogen fixing bacteria in soil and r_____ n_____ of legumes turn n______ gas to am____

8. Eutrophication Fertilisers drain into ponds and rivers
Algae “bloom” and turn the water green
Light cannot reach the other water plants
Plants die and decay
Decay microbes increase and use up oxygen
Animals suffocate and die