food production

• insecticides = kill insects
• herbicides = kill weeds
• greenhouses + polythene tunnels increase yield by controlling the temperature, water levels, fertiliser and CO2 levels to get the best photosynthesis and growth rates
• GM crops have been developed with resistance to pests or herbicides, increased yields, drought tolerance and nutritional value
• increasing CO2 levels in greenhouse = increases photosynthesis and produces more glucose = better growth
• increasing temperature in greenhouse = increases rate of metabolic reactions (eg. respiration)
• greenhouses/polythene tunnels protect against harsh abiotic conditions outdoors and can produce crops in other conditions and growing seasons
• fertiliser increases crop yield:

  • adding manure: increases concentration of nitrates and minerals - released by bacteria when it decays
  • artificial fertiliser: inorganic - applied directly to crop with the minerals it needs
• pesticides:

  • adv = protect crops from damage, increase yield
  • dis = can kill all insect communities = reduce food sources and damage food web, rain washes pesticides into water = eutrophication, evolving pests to become resistant
• biological control:

  • adv = predator reduces pest number - reduce crop damage, lasts longer, targets specific organisms, don't need to reapply
  • dis = can begin to eat other organisms, have no natural predator themselves - become overpopulated and disrupt food chain, cannot eradicate a species - keep it manageable, only in greenhouses