key words 8

• carbon sequestration


  any process which removes carbon dioxide from the atmosphere

  -> afforestation
• feedback mechanism


  a process where an action has consequences which affect the original action
• peat bog


  a wetland area with an accumulation of dead plant material, especially moss
• permafrost


  a layer of soil in which the water is permanently frozen, often trapping bubbles of gases e.g methane
• ploughing 


  the cultivation of the soil by turning over the surface layer
• tied ridging 


  a method of reducing soil erosion by creating a grid of raised ridges to collect rainfall

  -> increases filtration, reduces runoff
• tillage


  the cultivation by turning the soil

  e.g ploughing
• Universal soil loss equation (USLE)


  a formula that can be used to calculate rates of soil erosion