The desert is growing outwards there are quite a few countries under threat from desertification and every year thanks to global warming the Sahel is growing. This is the first idea and I tend to agree with his because as the planet warms up the arid regions are going to spread outwards and more and more of the country will be covered.
The second idea suggests that there are pockets of degradation around areas of human activity and as the land becomes over cultivated and over grazed it starts to turn into desert but I think this idea is not as correct as the first idea but this could happen in the most extreme circumstances.
(b) Using an area you have studied examine the extent to which desertification is caused by human activity.
To what extent has the humans had on the advance of desertification in the Sahel region.
The characteristics of overgrazing these are when the number of grazing livestock exceeds the carrying capacity. The United Nations has declared in recent year the amount of animals being raised in the Sahel has more than doubled. The consequences of this are the removal o vital ground cover which makes the soil more susceptible to wind erosion. Also the trampling of vegetation this destroys ground cover and also compact the soil.
The characteristics of Over-Cultivation are when the crop yield exceeds the field’s carrying capacity. This is caused by an increase in the growing of cash crops also shorter fallow periods and also the use of agricultural machinery which compacts the soil. The consequences are reduced soil nutrient 90% of the soils in the Sahel are phosphorus deficient also there is accelerated soil erosion when crop cover is low or when land is compacted by machinery and finally in over cultivation there is salinisation and water logging from inefficient irrigation.
The characteristics of Soil erosion are when top soil is removed by wind or rain. This is caused by Over-Cultivation, Overgrazing and deforestation and also cultivation of steep slopes. The consequences of this are loss of soil depth ad loss of soil fertility and also the reduction of soil moisture but after saying all that population increase does not mean it affects soil erosion.
The characteristics of Salinisation are when there is an increase in the salt levels in the soil this is caused by poor irrigation or by too quick evaporation and deforestation. The consequences of salinisation are very serve including toxic soil and increase in the soils ph the loss of soil structure and finally accelerated salt weathering.
To conclude I have talked about the affects and consequences of different things that might contribute to the desertification of the Sahel region.
