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16 Cards in this Set
- Front
- Back
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Describe the location |
They are located 20-35 north and south of the equator located in high pressure belts so very few or cloudless conditions. Located mainly in continents like Africa and Asia covering countries like Egypt, Chad,Niger and Australia. |
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Describe the conditions |
A desert is an area which has less than 250mm of rainfall a year. The temperature range is high, varying to 20 degrees celsius. |
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What is desertification |
The turning of land into desert. It usually occurs in areas which are semi-arid and already considered marginal. |
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Describe the location of an area vulnerable to desertification |
The Sahel is a region of land located on the southern edge of the Sahara in the northern half of Africa, covering countries like Niger, Chad, Sudan and is a place suffering from drought vulnerable to dissertation. |
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Factors affecting desertification |
Deforestation Climate change Over cultivation Over grazing |
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Describe how climate change affects desertification |
the higher temperature means an increase in evapotranspiration, reduced condensation so less rainfall. This can lead to drought so rivers will dry up and plants will die so the land turns bare without the protection from any grass or trees |
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Describe how over grazing affects desertification |
where there is too much livestock for the amount of grass available so any protective grass is stripped away. Due to the lack of water, animals have to be taken away further distances for a source of water meaning more loss of vegetation at an increased distance so there is lack of shade, lack of anchoring (from the roots) and decrease in nutrients. Blown away by heavy wind or washed away by heavy rain |
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Describe how deforestation affects desertification |
People chop down trees for fuel wood so the protective cover of vegetation is removed and the soil retains less less moisture and dries out.The roots no longer binds the soil together and is open to erosion and is blown away or washed away with increased surface run off. |
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5 strategies to reduce desertification |
Planting trees Zai pits terracing Magic stones/bunds Stop overgrazing |
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Describe planting trees |
Used in the Thar desert-India The great green wall in the Sahel Roots help to anchor soil which helps to stop soil erosion Leaves and branches provide shade and shed heavy rainfall for the soil The decomposition also helps to return minerals Plant material and seed pods for animals to eatCheap and long term Provides fuelwood and grazing from animal |
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Describe terracing |
Digging ridges or steps at a hillside Prevents quick runoff of rainfall which can wash away the surface soil Cheap to build |
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Describe zai pits |
Holes dug into the ground with manure and termites with a seedling in the middle Termites dig into the ground which brings along the manure so fertilizes the soil |
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Describe magic stones |
Used in parts of Burkina Faso Using basic tools to transport stones Build low stone walls along slopes which traps the water and soil when the rain washes it away Has increased the number of crops by 50% |
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Describe the location of the Thar desert |
The Thar desert lies across NW India and Pakistan. Mainly in the Indian state of Rajasthan being the most densely populated in the world. |
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What are the challenges for development in the Thar desert? |
Extreme temperature Temperature above 50 degrees celsius Hard for workers working outside-farmers Live stock-cattle and goats need shade for protection High rates of evaporation-high temperature and strong winds Demand for water increasing-farming and industry Low annual rainfall High pressure region Drinking water in ponds (natural and man made) Few rivers-River luni Underground sources (aquifers) wells,not good quality Very limited road network |
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what are the opportunities |
Valuable reserves of minerals and material to be mined-gypsum and phospherite Marble mined in Jodphur Desert Safaris on camels attracts tourists-Jaisalmer Wind turbine farm-Jaisalmar Solar farm Commercial farming using irrigation like the Indira Gandhi canal |
