Rural Flashcards
Rural land degradation
This is the gradual destruction or a reduction in the quality and quantity of a natural environment.
It is mainly caused by humans
Desertification
This is when sever land degradation causes the environment to become increasingly arid
90% of the people who are affected by desertification live in the worlds poorest countries.
The Process of Desertification
β’ If vegetation is removed it exposes bare soil to erosion by wind and water.
β’ This degradation of the soil means that vegetation cannot grow back again.
The Process of Desertification
Wind Erosion
Surface creep β the slow rolling of larger particles across the surface.
β’ Saltation β medium particles which are too heavy to lift are bounced across the surface.
β’ Suspension β the lightest particles are suspended in the air column.
β’ Only the smallest particles can be moved by the wind. Larger and therefore heavier particles will remain in place.
The Process of Desertification
Water Erosion
- RAIN SPLASH β the impact of raindrops on the surface of a soil causing the soil particles to be moved. Resettled sediment blocks soil pores resulting in lower infiltration.
β’ SHEET EROSION β the removal of a thin layer of surface soil which has already been disturbed by rain splash. It is the finest soil particles which contain the nutrients and organic matter. - RILL EROSION β small eroded channels, only a few centimetres deep (up to about 30cm).
β’ GULLY EROSIONβsteepsidedwater channels which can cut deeply into the soil after storms. Rain water running into the gully erodes it causing it to widen.
The Process of Desertification
After
β’ After the unprotected, dry soil surface is blown away or washed away by floods an infertile lower soil layer remains that bakes in the sun becoming an unproductive hardpan.
β’ This hardpan subsequently dries and cracks open up.
β’ When it rains clay in the soil expands forming an impermeable layer that causes large volumes of runoff.
Causes of rural land degradation
Population increase
- Population in the Sahel has increased from 30 million in 1950 to 100 million in 2015
- more people require more water which lowers the water table and dries the ground out
- due to climatic changes further north people have migrated south into the Sahel increasing pressure on resources
- wars -e.g. Civil wars in Somalia and Sudan cause large summers of refugees. They migrate to other areas and put an increasing strain on the land and water resources
Causes of rural land degradation
Over cultivation
Increases in population means that more food is required. In order to maximise crop yields farmers:
- cultivate marginal areas( areas of land that is not productive or fertile/ not Normally used for agriculture) which are more vulnerable to erosion and better suited to grazing
- reduce fallow periods( allowing the fields to rest between crop yields)
- do not use crop rotation (different crops are alternated/ moved on in a cycle to balance the soil fertility)
Causes of rural land degradation
Overgrazing
Traditionally animals and nomads would follow a he rain which would allow plats time to recover. Now people stay in one place (sedentary farming) meaning that the plants are continually eaten and cannot regrow or hold moisture in the ground.
- when there is above average rainfall numbers of cattle increase so when droughts occur there are too many cattle and they destroy the vegetation.
Causes of rural land degradation
Irrigation
Inefficient irrigations use too much water. They use up groundwater supplies and can lead to salinazation of the soil as excess water is evaporated causing salt to build up and soils to become infertile.
Causes of rural land degradation
Deforestation
In the Sahel, wood is the main source of fuel for cooking. It is also a vital building material used for everything from shelters to fences( in Eritrea, a traditional home needs 100 trees to construct it)
- when trees are cut down runoff increases and the soils is removed. The soil can no longer hold moisture and it dries out and becomes infertile.
- as more trees are cut down, animal manure is used for fuel instead of being spread in the fields which would help to hold moisture in the soil.
Causes of rural land degradation
Changing nomadic lifestyles
- due to political changes, countries have begun to restrict cross border movement. This limits the ability for nomads to move their beards from dry to wet areas. As a result, nomads are forced into villages and in dry years, their heards overgrazed areas.
Causes of rural land degradation
Climate change
Successive years of below average rainfall have caused seasonal rivers and waterholes to dry up and the water table to fall. Higher temperatures mean increased evapotranspiration and reduced condensation and therefore less rainfall. Non - drought resistant vegetation then dies.
Impacts of rural land degradation
- Crop failures, livestock deaths, reduced food supply, malnutrition and famine.
- Erratic rains
- Increased infant mortality and death rates
- Collapse of nomadic way of life- forced to settle into villages causing further pressures
- Gully formation
- Migration to urban areas causing shanty towns
- Soil compaction
- Conflict for resources within and between countries (refugee camps)
- Soil structure deterioration
- Reliance on international aid
- Endemic disease and illness
- Breakdown of farmer/nomad relationship β Yatenga, Burkina Faso
- Wind erosion removes soil
- Advance of desert β Sahara into the Sahel
- Water table lowering
- Intensified drought due to albedo effect.
Management of Rural
Land Degradation
Reafforestation
Trees are selected for their rapid growth. Reafforestation is a long-term action since tree growth is slow. They play several roles in preventing degradation:
β’ they fix the soil with their roots so erosion doesnβt happen.
β’ they act as wind breaks to protect crops.
β’ they make the soil more fertile.
β’ they trap water in the soil with their roots.
β’ they supply food (fruit), an export (Gum Arabic tree) and fodder for animals in the dry season.
Examples:
Desert plant gene bank in Tunisia. Seeds are free for
farmers to use.
In Gambia communities get 85% of forest revenues.
