Food Production Flashcards
Why do farmers choose to grow crops in greenhouses?
- Artificial heating
- Artificial lighting
- Additional CO2 in the air
- Regular watering
You know the reasons why farmers use greenhouses, however, how does each benefit work?
- The transparent material allows sufficient natural light in for photosynthesis during the summer. Additional lighting gives a ‘longer day’ during the winter for valuable crops.
- The greenhouse effect also raises the temperature in the glasshouses
- Burning wood or fossil fuels increase the temperature when the external temperature is too cold.
- Water vapour maintains a moist atmosphere and so reduces water loss via transpiration
What do greenhouses increase the rate of?
- Increase the rate of photosynthesis
What are the two types of fertiliser?
- Organic
- Inorganic
What is an organic fertiliser made from?
- Made from the faeces of a range of animals
What is inorganic fertiliser made from?
- Inorganic compounds
What are the advantages and disadvantages of Organic fertilisers?
- Advantages:
- Improves soil structure
- Greater range of minerals
- Less cost to farmers
- Releases minerals over a longer period of time
- Disadvantages:
- Slow acting
- Harder to apply than inorganic fertilisers as it is bulkier
- May contains pests
What are the advantages and disadvantages of inorganic fertilisers?
- Advantages:
- Mineral ions released immediately so fast acting
- Contents are known
- Easy to apply
- Disadvantages:
- Can lead to eutrophication as fertiliser is soluble
- Requires regular reapplication
What is nitrogen used for in plants?
- Making proteins
What are pests?
- Pests are organisms which reduce crop yield
How can we control pests?
- Chemicals called pesticides
- Biological control (using other organisms to reduce numbers of pests)
What are the four types of pesticides?
- Herbicides (kill plant pests)
- Insecticides (kill insects)
- Fungicides (kill fungi)
- Molluscicides (kill molluscs)
What is a problem with Biological control?
- It never eradicates the pest it only reduces the number of pests in a given area.
What are the methods of biological control?
- Introduce a natural predator
- Introduce a herbivore
- Introduce a parasite
- Introduce a pathogenic microorganism
- Introduce sterile males
- Using pheromones
What are the advantages and disadvantages of pesticides?
- Advantages:
- Reduces pest population instantly
- Can kill the whole population of pests
- Disadvantage:
- Expensive as you need regular application
- Pest can become resistant to chemical
- Not specific (will kill other insects as well as the pest)
- Chemical can concentrate on all organisms higher up the food chain