soil :(

• what is soil?

  • weathered bedrock + organic matter from vegetation
• what are zonal soils?

  mature soils that have developed from interactions between climate , vegetation and parent rock across a significant period of time
• what percentage of soil is used for agricultural around the world is degraded?

  40%
• soil is lost at ? times the rate at which it is naturally replenished?

  10-40 times
• food production will decline by 30% over the next 30-50 years without?

  soil management
• what is waterlogging?

  spaces between soil particules fill with water
• waterlogging causes

  • too much irrigation
  • soils with few airspaces fill up quickly
• waterlogging impacts

  • plant roots surrounded by water , limits growth and rots them quickly
  • land = hard to plough
  • water decreases soil temperatures = reduce crop growth
• waterlogging management strategies

  • avoid over-watering crops
  • change composition of soil e.g add sand to clay soil
• what is salination?

  the build up of salts in soils
• salination causes

  • high temperatures draw water to surface , evaporates = leaves behind salt
  • dry climates don't have enough rainfall to wash salts away
  • some fertilisers contain too much salts , leaving salt in soil
• salination impacts

  • salt is toxic to some plants , reduce crop yield or kill crops
  • salts stop crops from absorbing water they need from soil
• salination management

  • salt tolerant plants
  • avoid waterlogging
  • don't use too much water
• what is structural deteration

  pure space in soil lost
• structural deterioration causes

  • removal of vegetation = plant roots help to maintain soil structure
  • salination in clay soils , salt causes clay particules to clump together
• structural deterioration impacts

  • land = hard to plough
  • difficult for plan roots to grow if soil is too compact
• structural deterioration management

  • maintain vegetation cover
  • avoid salination
• soil erosion causes

  • agricultural processes e.g ploughing
  • clearing vegetation
  • topography e.g Nepal , steep relief
• soil erosion problems

  • remove nurtrients , reduces soil abilities to hold water
• soil erosion management strategies

  • crop rotation
  • windbreaks
  • terracing
  • contour ploughing
  • mulching
• what is crop rotation?

  farmers plant cover crops to help maintain soil until main crop is grown again
• what are windbreaks?

  hedges or trees which are barriers against wind erosion
• what is terracing?

  steps cut into hillside and it slows down the movement of water down the slope
• what is contour ploughing?

  ploughing areas across slope rather than downslope , this stops rainwater flowing down hill so quickly
• what is mulching?

  mulching is when you cover the top layer of soil with a layer of plant materials , this protects soil from erosion
• what is leeching?

  water washes away nutrients