Effects Of Overgrazing On Soil

Human influences on soil erosion

Aspect 1: The effect overgrazing has on soils.

Overgrazing is when a farmer stocks (Keeps) too many animals in their land. Examples of such animals are sheep, which pull up the roots of plants, cattle, which kick up the top layer of dirt which is then blown away by the wind, and goats. These animals all damage the surface of the soil and speed up soil erosion.

These animals eat the vegetation cover of the area and their hooves dig into the soil, which compacts it into a hard surface in dry regions, meaning it is given a platy structure, which is a very poorly drained soil structure. This prevents the growth of grass and also stops water from leaching into the soil. This process of water rolling over the soil

This means that the available land is under stress to develop food for the higher population, meaning that the land is over-cultivated and so aids soil erosion. For example, intensive cultivation of land in the soya plantations in South America can lead to overcropping.

In South America, the soil is fertilised, although the use of chemical fertilisers Is not advantageous to the land as much as manure is. Due to the overuse of fertiliser and the underuse of manure, the soil structure gradually becomes more damaged due to the effects of overcropping.

The effects caused by overcropping can be lowered through the use of organic manure, i.e cattle dung, to the soil through irrigation. However, in areas such as the Sahel, deforestation is also happening in some of the areas suffering from soil erosion. This means that people are using cow dung for fuel instead of as an organic fertiliser. This means that there is no cattle dung to fertilise the land.

Aspect 3: The effect desertification has on soils.

Desertification is defined as the spread of desert conditions into areas which have not previously experienced such conditions. An example of this is the expansion of the Sahel desert, which moves south at an approximate speed of 10 kilometres per

This is because the higher demand for food and fuel causes the removal of protective vegetation from the area, meaning that rain-splash erosion and aeolian erosion can occur.

The chance of desertification increases when an area is experiencing drought conditions. This is because the soil is already stressed by the processes of overcropping and overgrazing, and so a drought dries out the soil completely and causes it to become useless and desertified.

In Sahelian countries such as Chad and Niger, cash crops (Crops only sold for their monetary value) such as cotton and cashew nuts are grown in massive plantations as part of economic reforms known as structural adhustment programmes. This is because the owners of these farms receive debt relief for growing this crop. People are removed from the land in order to make room to expand these plantations. This causes the original inhabitants to be forced to live on poor land on the edges of the plantations.

The land in these areas is overgrazed and overcropped. There is also massive deforestation occurring and instead of a natural fertiliser, cow dung is used as a fuel. This further deprives the soil of valuable nutrients. These factors cause increased desertification in the region during a