Changing Landscapes

Land Degradation

  • Land degradation reduces the quality of and and its capacity to produce food.

  • Land degradation is caused by

    • overgrazing

    • deforestation

    • land clearing

    • collection of wood for fuel

    • industrialisation

    • mining

  • The United Nations Food and Agriculture Organization (FAO) estimates the world has 60 more years of crop growing left if do not modify our practices

  • FAO estimates 6 million hectares of farmland are needed each year to keep up with the global food demand, instead, 12 million hectares are lost through land degradation.

  • All minerals and ores used for modern technology and our lifestyles come from the Earth’s crust.

  • If the rock is close to the surface, it can be extracted through open cut mining, or underground mining, which damages the environment from dumping crushed rock around the mines.


Causes of Landscape Degradation

  • More than half of the worlds arable land is moderately or severely damaged.

  • Soil erosion, desertification and salinity are the most common forms of land degradation

  • 5 main causes-

    • overgrazing- 35%

    • deforestation- 30%

    • crop growing- 28%

    • collection of firewood for fuel- 6%

    • industrialisation- 1%

Soil erosion

  • Soil erosion is the removal of topsoil faster than the soil can form back and replace it.

  • Natural vegetation protects the soil.

Desertification

  • Desertification is the transformation of fertile land into dry, desert-like areas

  • This is caused by activities such as deforestation, overgrazing and poorly managed agriculture.

  • Unprotected, dry soil surfaces blow away with wind, or washed away by rain, leaving infertile lower soil layers that are unproductive

Salinity

  • Salinity refers to a high level of salt in the soil, which kills plants.

  • Salt underground is forced to rise when we remove trees with deep roots that keep water low in the ground, known as dryland salinity.

  • When extra water from irrigation enters the ground, it forces the water to rise, known as irrigated salinity