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03/05/23
Plants for FoodPlants for Food
How do fertilisers affect plant growth?
Lesson AimsTo review key ideas about plants
for food and study how fertilisers affect plant growth.
03/05/23
Learning outcomes
By the end of the lesson you should know / be able
•to link ideas about feeding relationships and photosynthesis
• that plants require a range of minerals for healthy growth
• that fertilisers supply these minerals to crop plants
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We need plants !
Write down 3 reasons to support this statement
Remember: The three main Remember: The three main types of nutrient are:types of nutrient are:
1. Nitrogen in the form Nitrates – used to make proteins
2. Phosphorus in the form of Phosphates – used to provide phosphorus to help photosynthesis and respiration
3. Potassium – helps the enzymes that are needed for photosynthesis and respiration
Remember: Lack of the three Remember: Lack of the three minerals would lead to a minerals would lead to a “Deficiency Symptom”:“Deficiency Symptom”:
Lack of nitrates:Small plant, yellow leaves
Lack of phosphates:Small roots and purple leaves
Lack of potassium:Yellow leaves with dead bits
Page 143 Page 143
• On your own :
a)What is a fertiliser?b)Answer questions 1- 3
• In groups of 3 or 4 :• Answer questions 4 -11 on newsprint
03/05/23
1.What is a weed?1.What is a weed?2.What is a weedkiller?2.What is a weedkiller?3. Why are they used ? 3. Why are they used ?
• Answer question1-4 page 145• Extension questions 5-11 p\age 146
• Remember your pondweed report is due in next lesson !
03/05/23
03/05/23
Advantages
Helping plants to growHelping plants to growFarmers can use a number of chemicals to help plants to grow:
1) Fertilisers
2) Herbicides
3) Pesticides
Disadvantages
Disrupt food chains
Provide nutrients
NPK
Too much of it can kill pond life
Kill weeds
Kill pests
Disrupt food chains
03/05/23Another disadvantage of Another disadvantage of pesticidespesticides
Insecticides can wash into a stream or lake where they are taken up by microscopic water plants. Consider the food chain:
Although the level of insecticides in the plants is small, it will build up through the food chain due to the number of organisms in each stage.
Small plants KingfisherMarine insects
Fish