Desert case studies Flashcards
Kenya desertification?
Solutions?
- A country in East Africa that lies on the equator
- 40 mill population
- Dry land account for 88% of Kenya’s total land surface
- Kenyan gov released report: warning that millions of Kenyans are increasingly threatened by desetification.
- National Action Programme on desertification - concluded that the phenomenon had “intensified and spread” in recent years.
- 64% of Kenya’s land area was subject to moderate desertification and about 23% vulnerable to severe desertifiaction.
Population growth/frequent floods has accelerated role of soil degradation in kenya. - The rehabilitations project of the Thugi riverbanks in the Kandara division inclide self-help and educating population on proper land use techniques and tree planting.
- Desertification community trust fund - facilitating research on desertification, enhance enviro mangament and raise public awareness.
- Enhanced community participation in enviro management - labour/local materials and management skills.
Desertification in the Niger?
- Landlocked country in central/Northern Africa and home to a growing problem of desertifiaction.
- 3/4 is desert
- One of Africa’s worst hit countries by D
- Winds in the Sahara can reach 100km/hr, carry sand far, erode rocks and decrease visibility to zero in severe storms.
- Pastoral zone to the North of Tanout, it is well vegetated with many bushes and trees.
- Acts as a green belt protecting farmers from the Sahara.
- Area - well vegetated - protects enviro from wind and water erosion.
Impacts: - Director of the National Department for Environment in Niger - claims that 250,000 ha are being lost each year through desertification. - the size of Luxembourg.
- If the deforestation of the greenbelt proceeds - desert will swiftly advance - desert encroachment.
- Land use for millet cultivation has become barren in the sand dunes in E Niger. - overcultivation.
Solutions: - Proactive measures - increasing perennials in agricultural areas. Sustainable solution - for farmers themselves to stabilise their enviro by intercropping edible perennials in their fields. - These perennials stabilise the soil against wind and water erosion and increase fertility.
- In 2000 the country adoptd the NAP to combat D and manage resources.
Ghana desertification?
- Common cause of land degradation is bush burning
- Result of poor farming methods
- 22,000 ha lost/year to bush fires
They pressurise the land during the dry season to produce much more crops than capable as well as overgrazing - Child malnutrition increased from 50% to 70%
Solutions:
- Ghana has authorised international agreements protecting biodiversity, endangered species, tropical forests, wetlands and the ozone layer.
- Catholic church has stepped in to encourage and help the communities as they are very religion based.
- NGOs and government agencies have stepped in.
- All helping to educate the population in bush fire control and land managament.
- In Gorizi they have set up 3 tree nursery’s and have been taught how to manage and care for them.
- Their good work has been rewarded in the form of water wells and more crop plantations - generated more money for the community.
Desertification in the Badia, Jordan
- Area of stony desert - eastern jordan
- Less than 150mm/year - much of which forms as torrential storms.
- Temps can soar to over 40 degrees in the summer - yet to below 0 degrees.
- Gulf war 1991 - large number of sheep available cheaply from Iraq - local farmers bought hundrds and grazed them - this overgrazing tipped the ecological balance and land quickly became desertified.
- Many people moved from the capital to Amman
Where was the highest ever temp recorded?
57.7 degrees was at Al Aziziyah in Libya in 1922.
Why do cloudless skies explain why there is such a high diurnal range in deserts?
The cloudless skies explain the high diurnal range, as temperatures drop very rapidly at night, with hot deserts losing twice as much heat at night as the more humid latitudes.
Hot deserts are classified as receiving less than 250 mm of rainfall, but rates vary greatly around the world.
Give an example?
Places like Iquique in the Atacama Desert in Chile receive almost no rain and are the driest averaging less than 15 mm a year, with the central Sahara receiving a similar amount.
American deserts receive slightly higher amounts at around 280 mm.
Desert soil?
Around 17% of the earth’s surface has desert soils. The extent of desert soils varies in different continents: Australia has about 44 %, Africa 37% and Eurasia 15%.
Why do arid soils tend to have limited variation between horizons?
With a lack of water there is little downward movement of minerals (leaching), and arid soils tend to have limited variation between horizons.
Which desert soils are often used for cultivation?
Sierozems are often used for cultivation and with continued irrigation calcium-rich B horizons can develop beneath the thin A horizon, with rich accumulations of calcium carbonate or gypsum giving a lighter colour.
Name for succulent plants and an example:
xerophytes - all cacti and non-cacti like aloes.
What is the name for plants with shallow (less than 10 cm) and very wide extensive root systems?
Examples?
Phreatophytes
The roots of the 12-18 cm high Saguaro cactus can extend horizontally to the same distance as the height of the plant.
The 60cm tall Cholla cacti lives in extremely arid conditions and has roots that extend up to nine metres.
Drought tolerant plants?
Desert plants are also drought tolerant, or ephemerals, with adaptations like becoming dormant or losing their leaves during extreme dry spells, often appearing dead for months or even years at a time.
A number of plants, including some ephemerals, will try to avoid drought altogether by having extremely short life cycles; coming into bloom rapidly after rainfall, then channelling all their life energy into producing seeds which can themselves then lay dormant until a future rainfall event.
Example of rainshadow effect:
The effect of the Southeast trade winds from the southern Atlantic meeting the Andes and the effect on the Atacama desert in the west of South America.
