Plants- intensive farming

• What is the limitation for growing crops?

  The area available to grow crops is limited
• How do farmers improve efficiency in crop production?

  By maximizing photosynthesis
• What effect does increasing light intensity have in greenhouses?

  It increases the growth of crop plants
• What materials can be used to construct greenhouses for maximum light transmission?

  Glass or alternate materials
• How can plant growers position plants for better growth?

  For maximum light absorption
• What is the purpose of artificial lighting systems in greenhouses?

  To provide optimum wavelengths for photosynthesis
• How do artificial lighting systems affect the growing season?

  They lengthen the growing season
• What is one method to increase carbon dioxide concentration in greenhouses?

  Using paraffin heaters
• How can industrial processes contribute to carbon dioxide levels in greenhouses?

  By using cleaned carbon dioxide wastes
• What is a method of applying liquid carbon dioxide in greenhouses?

  Through pipes
• What is a potential downside of using liquid carbon dioxide?

  It can be expensive
• How do fungi contribute to carbon dioxide levels in greenhouses?

  By respiration as mycelium
• What is the typical concentration of carbon dioxide in greenhouses?

  Around 0.1%
• What happens to carbon dioxide concentration above 1%?

  It becomes toxic and acidic
• What role do irrigation systems play in greenhouses?

  They help to increase yields
• Why do growers spray plants with water in greenhouses?

  To keep humidity high
• What is the balance growers must find regarding humidity?

  High humidity promotes fungi growth
• How does temperature affect plant growth in greenhouses?

  Increased temperatures increase photosynthesis
• What is a potential issue with increased temperatures in greenhouses?

  Respiration can reduce yields
• Why might growers use compromise temperatures in greenhouses?

  Heating can be expensive
• What are chemical pesticides used for?

  To kill organisms that reduce plant growth
• Why are weeds harmful to crop plants?

  They compete for resources with crop plants
• What role do fungi play in relation to plants?

  They can cause plant diseases
• How do insects affect plants?

  They may consume and damage the plants
• What can happen if pesticides are not biodegradable?

  They can accumulate in organisms over time
• How does pesticide concentration change in food chains?

  It increases at higher levels of food chains
• What is bioaccumulation?

  Build-up of toxic substances in living organisms
• What is an example of a non-biodegradable pollutant?

  DDT insecticide
• When was DDT used and for what purpose?

  In the 1940s to kill mosquitoes
• Why does DDT accumulate in body tissues?

  It is not very soluble in water
• How does DDT concentration change in the food chain?

  It increases greatly at higher levels
• What effect can DDT have on top-level consumers like ospreys?

  They may lay eggs with thinner shells
• Why are thinner eggshells problematic for ospreys?

  They are more likely to break
• biological control is an alternate to using pesticides. by releasing a natural predator in the crop growing area, the number of pests can be reduce. this can have have unforeseen consequences as they number of different organisms in the food web are changed. there have been examples of the predator becoming a more serious pest than the original problem.
• What is the extreme form of growing crops in glasshouses called?

  Hydroponics
• What replaces soil in hydroponics?

  A mineral solution
• What is a benefit of removing soil in hydroponics?

  No risk of soil organisms causing disease
• What must be done to support plants in hydroponics?

  They must be supported artificially
• How can growers control plant growth in hydroponics?

  By monitoring and adjusting mineral concentrations
• Where can hydroponics be used effectively?

  In regions with little or no soil