1. Plants need minerals too
IT’S A GREEN WORLD
Plants need minerals too

2. Starter What is ‘slash and burn’ agriculture?
What problems can arise from using this method?

3. Plants need minerals too
Learning objectives
Success criteria
Understand that:
The production of many important compounds by plants requires elements that are obtained from soil minerals
Fertilisers contain minerals
Complete a table stating what how various minerals are used by plants Completion of worksheets on fertiliser usage

4. What do plants need for a balanced diet?
Plants need carbon dioxide and water for photosynthesis.
Do they need any other nutrients to keep healthy?
Just like humans, plants need a balanced diet
that includes small amounts of mineral elements.
What mineral elements do they need?

5. What minerals do plants need?
Plants need mineral elements for healthy growth.
Some of the most important minerals needed by plants are:
nitrogen
nitrates
phosphorus
phosphates
potassium
potassium ions
magnesium
magnesium ions
Students to take notes
How do plants obtain these minerals?
The mineral elements are found in salts dissolved in water.
Plants obtain minerals when they absorb water from the soil.
What type of salt are each of these elements found in?

6. What are minerals needed for?
Use p67 of the textbook to complete the table below
Minerals
How mineral is used in plants
What happens to these minerals
Nitrates
Phosphates
Potassium compounds
Magnesium compounds
Nitrogen is used to make amino acids which are then joined together to make different proteins
Used to make proteins (for growth)
Phosphorus is used to make cell membranes and DNA ( which carries genetic information)
Used in respiration and growth esp in roots
Used to make some enzymes needed in respiration and photosynthesis
Used in respiration and
photosynthesis
Used to make chlorophyll molecules
Used in photosynthesis

7. Where do minerals come from?
What are the sources of minerals in the soil?
Rocks: The minerals in rocks are slowly dissolved by slightly acidic rainwater. These minerals are washed into the soil.
Natural fertilizers: Animal faeces and the decay of dead plants and animals return minerals to the soil.
Artificial fertilizers: These
contain a ready-made mixture
of the minerals needed by plants.

8. Task - Fertilisers Complete worksheet B4d3 – Rothamsted experiment
Extension – complete worksheet B4d2 -Nitrogen fertilisers

9. B4d3 – Rothamsted experiment
As a control/comparison
Potatoes do not need much nitrogen but wheat does
Field 4; a fertiliser containing nitrogen, phosphorous and potassium would be expensive – the increase in crop yield may not justify the expense
Soil type (clay, sand, chalk), drainage, aeration, climate conditions, pests, disease

10. B4d2 – Nitrogen fertilisers
0.7 tonnes/hectare
This uses ‘the law of diminishing returns’ – by doubling the amount of fertiliser from 0 to 50, the crop increases from 2.5 to 7 tonnes/hectare, almost three times the size If the amount of fertiliser is again doubled from 50 to 100 tonnes/hectare, the crop only increases from 7 to 8.4 tonnes/hectare
It is tempting to state the highest amount of fertiliser, as this would give the largest crop, however by spending more and more money, the farmer’s increase in yield becomes less and less; the correct amount of fertiliser depends partly on its cost Most farmers would choose 50 kg of fertiliser/hectare

11. Plenary
Organic farmers do not use artificial fertilisers.
Who would pay more for organic food and why?

12. Plants need minerals too
Learning objectives
Success criteria
Understand that:
The production of many important compounds by plants requires elements that are obtained from soil minerals
Fertilisers contain minerals
Complete a table stating what how various minerals are used by plants Completion of worksheets on fertiliser usage