physical and human causes of land degredation

Question 1

6 physical causes

Answer 1

Regions such as Sahel have unpredictable climates – they can experience flash floods and drought conditions

With little rain, plants can’t grow so there are no roots to hold the soil together

The soil dries out and is washed or blown away easily, leading to desertification as roots can no longer anchor the soil which in turn is easily blown away

Flash floods also wash away the exposed top soil

Water shortages caused by major drought can lead to a drop in the water table meaning many plants die as their roots cannot reach the water

Frequent water shortages lead to the need for more wells, lowering the water table further

Question 2

8 human causes

Answer 2

Many farmers moved away from traditional farming techniques and grew cash crops, such as cotton and rice. Monoculture has led to the soil becoming infertile in some areas

Overgrazing destroys the vegetation cover, leading to soil erosion and poor irrigation methods lead to evaporation of stagnant water, leaving a salty infertile crust

Increased population had led farmers to use more of the land for arable farming, but this is not viable for sustained crop production and increases the rate of desertification

In many regions of Africa the birth rate is high in there is significant population growth. This has placed increase pressure on countries to increase food production

The shortage of firewood means families have to use more animal dung and crop residue for their domestic energy requirements. In the long term this results in lower crop yields.

The concentration of livestock in these areas results in vegetation being stripped down to its roots leaving the soil exposed

The increased need for timber in construction and for firewood has led to widespread deforestation

Deforestation removes the binding effect of tree roots and prevents trees from reducing wind speed