GCSE Geography | Reducing the Risk of Desertification (Hot Deserts 10)

There are several ways to reduce the risk of desertification in semi-arid areas such as the Sahel.

Afforestation

Afforestation is a good strategy to reduce the risk of desertification as tree roots bind the soil together and leaves provide shade to stop the ground from drying out, as well as providing leaf litter for nutrient cycling.

The Great Green Wall is an African-led project with an epic ambition: to grow an 8,000km natural wonder of the world across the entire width of Africa. Its goal is to provide food, jobs and a future for the millions of people who live in a region on the frontline of climate change. Once completed, the Great Green Wall will be the largest living structure on Earth and a new Wonder of the World. The Great Green Wall is an example of an initiative where countries are working in partnership with one another. 11 countries signed an agreement in 2010 to begin planting this ‘wall’. The plan is to plant a 15 km-wide strip of land with trees and shrubs across the width of Africa. It is hoped that the wall of vegetation will help prevent further soil erosion from the Sahel and improve incomes.

However the 'wall' hasn't been entirely successful as in some areas local people have used the newly planted trees for building materials and firewood - and it will only be an effective way of stopping the Sahara Desert encroaching the Sahel, if all countries maintain their tree cover.

Water and soil management techniques

These are usually small-scale and use appropriate technology – so use methods and materials that don’t cost much and are easy to maintain, which is important for the communities in developing nations who are most likely to be affected by desertification.

Bunds - 'magic stones'

In some parts of the Sahel, such as Burkina Faso, local communities have constructed low lines of stones known as bunds or magic stones along contour lines. These low stone walls are between 0.5 and 1.5 metres high and have been built by local people, using basic tools and trucks to transport the stones. These contour traps prevent soil and water being washed down the slope during heavy rainfall, so more water infiltrates the soil and less is lost through run-off. This has helped increase crop yield by up to 50%, and reduces the risk of desertification significantly.

Sand dams

Some communities in Kenya have used sand dams to reduce the risk of desertification. There are three stages to this strategy...

Firstly, a sand dam has to be built. This is done by building a dam across an ephemeral river which causes sand to be deposited behind it. An ephemeral river is one that is most often dry but flows for brief periods after rainfall. When the river has water in it, the sand becomes saturated and people can dig down into the sand to find water for several months after the river has stopped flowing.

Secondly, fields surrounding the river will be terraced, with steps built into the land meaning that the soil won't be washed away when it rains, and water will soak into the ground instead (these work like the bunds described above).

Thirdly, local communities will plant trees so the tree roots can hold the soil together and keep water in the ecosystem. They will usually choose fruit trees which can provide food, or trees that have bark which is useful for medicine.

Drip irrigation

You can also use drip irrigation, where water drips slowly onto the ground from pin-sized holes in a hose lying on top of the soil. This minimises water loss through evaporation.

Fuel efficient stoves

Fuel efficient stoves use significantly less firewood than traditional stoves, and are well insulated to stay hot for much longer. This means that people don't need to cut down so many trees, which leaves trees in place with roots to hold the soil together.