The nitrogen & phosphorus cycles

  • recall that nutrients are recycled within natural ecosystems, exemplifed by the nitrogen cycle and the phosphorus cycle
  • describe the role of microorganisms in recycling elements such as phosphorus and nitrogen, to include:
    • The role of saprobionts in decomposition.
    • The role of mycorrhizae in facilitating the uptake of water and inorganic ions by plants
    • The role of bacteria in the nitrogen cycle in suffcient detail to illustrate the processes of saprobiotic nutrition, ammonifcation, nitrifcation, nitrogen fixation and denitrifcation
  • describe and explain the use of natural and artifcial fertilisers to replace the nitrates and phosphates lost by harvesting plants and removing livestock
  • describe and explain the environmental issues arising from the use of fertilisers including leaching and eutrophication