Farming

• What are the types of features are controlled by farmers?

  Temperatures, light intensity, carbon dioxide levels, mineral irons in soil
• How is temperature controlled?

  Using a greenhouse to increase temperature
• How is light intensity controlled

  Artificial lights
• How are carbon dioxide levels controlled

  Burning fossil fuels in greenhouses
• How are mineral ions in soil controlled

  By adding organic/inorganic fertiliser to soil
• Why should the temperature be controlled

  As it will be the correct temperature for enzyme controlled reactions
• Why should light intensities be controlled

  As they maximise light levels for photosynthesis

  More light means more photosynthesis
• Why should carbon dioxide levels be controlled

  Increases the temperature

  Provides CO2 for photosynthesis
• Why should minerals ions in soils be controlled

  nitrates are used to make amino acids which help plants grow

  Magnesium is used to make chlorophyll in plants
• What do plants need to grow?

  Water, CO2, O2, light, phosphates, potassium

  Magnesium

  Nitrates

  Warmth
• How do phosphates help plants grow?

  They convert the sunlight into food for the plants
• what is the role of temperature in green houses

  • a key factor in a greenhouse is increased temperature
  • This increases the rate of the enzyme controlled reactions
  • Therefore the rate of photosynthesis increases
• what is the role of light intensity in green houses

  • glass allows sufficient natural light in for photosynthesis during the summer
• what is the role of carbon dioxide levels in green houses

  • burning fossil fuels raises the temperature when the external temperature is too low
  • It also produces carbon dioxide and therefore increases the level of carbon dioxide in the greenhouse
  • Carbon dioxide is needed for photosynthesis
• What else maximises photosynthesis

  • water supply
  • Humidity
  • Level of mineral ions
• what Happens when glucose and nitrates are mixed together

  They made amino acids

  Many amino acids equals more protein

  More protein makes the plants grow so there is more yield
• What do fertilisers do?

  They can increase the yield of crops
• How can fertilisers increase crop yield?

  • increase the level of nitrates in the soil
• What happens when nitrates are absorbed by the soil?

  They are absorbed by the roots by active transport and used by the plants to make amino acids
• How can fertilisers increase crop yield

  They increase the levels of other mineral ions e.g magnesium
• What are the two types of fertiliser

  Organic and inorganic fertiliser
• What is organic fertiliser

  It is made from animal faeces mixed with straw
• What is inorganic fertiliser

  Is made from a specific concentration of various mineral ions
• What are the advantages of using organic fertilisers

  • slow release meaning less risk of leaching
  • Less likely to have negative effects
  • Cheaper
  • Good for soil structure
  • A greater range of mineral ions
  • Higher in antioxidants
  • Stringent regulations
• What are the disadvantages of using organic fertilisers

  • slower process
  • Require microbial activity
  • Can stimulate in excessive growth in other places
  • Attracts vermin or pathogenic bacteria
  • Smells
  • Difficult to apply
  • Not fast acting due to decay
• What are the advantages of using inorganic fertilisers

  • Easy to apply
  • Fast acting mineral ions are released immediately (soluble)
  • Mineral ion content known
• What are the disadvantages of using inorganic fertilisers

  • nitrates are easily leached
  • Need to be applied several times
  • Expensive
  • damage to soil structure as they do not replace organic matter lost
• What are pests

  They are organisms that reduce the yield of crops.
• How are pest controlled

  • chemicals called pesticides
  • Using another organism to reduce the number of pest- biological control
• What are pesticides

  Pesticides are used to kill pests and so improve the crop yield
• What are herbicides

  They kill plant pests. For example weeds.
• What do weeds do?

  Weeds competes with the crop for mineral ions, light, water and carbon dioxid. The crop will get fewer ions or less light- less photosynthesis meaning a lower yield
• What are insecticides?

  Chemicals used to kill insects.
• What is biological control

  It is using another living organism regather than a toxic chemical, to reduce the numbers of pests.
• What is a feature of biological control

  It never eradicated a pest. If all the pests Are killed then the control organisms wood die from a lack of food. This aims to reduce the number of pests so they no longer cause efficient damage
• What are methods of biological control

  • introducing a natural predator
  • Introduce a herbivore
  • Introduce a parasite
  • introduce a pathogenic microorganism
  • Introduce sterile males
  • Using pheromones
• What is the effect of using Sterile predators

  These mate With females but no offspring are produced from mating, so numbers fall
• What is the effect of using pheromones

  • the animal sex hormones are used to attract males or females which are then destroyed reducing the reproductive potential of the population
• What is the effect of using a pathogenic microorganism

  • viruses are created to control an animal population
• What is the effect of using a natural predator

  it allows the prey to be eaten so reduces population