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| The Earth's Changing surface |
It is not only the activity below the Earth's crust which is changing the Earth's surface but contributing to the changes are also the effects of weathering and erosion. Both rocks and soil can be worn or eroded away by wind and water. When soil is left bare strong winds or heavy rainfall carry away the fertile topsoil. Lack of topsoil makes the land infertile and bare.
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The biggest factors which contribute to soil erosion are regular deforestation or improper farming. Another factor which could cause soil erosion is uncontrolled grazing by animals in areas with less vegetation. The fertile topsoil is held together in place by the roots of plants thus any area which is devoid of plant and trees would eventually erode. Wind is also capable of eroding hard rocks, this phenomenon is most common in the deserts or barren rocky terrain. As the wind blows, it carries with it small particles of sand which collide against rocks thus producing a sand blasting effect and in turn eroding the rocks. Like wind water can also cause an equal amount of damage.
When heavy rains take place, the flowing water carries with it the top soil from barren land. In relatively colder places rain water seeps into the cracks of rocks. During the daytime this water seeps into the cracks of rocks. During the daytime this water expands while it contracts, by freezing at night. This expansion and contraction eventurally cracks open the rocks. Soil erosion can have devastating effects. Deserts are devoid of vegetation and as such there is nothing to hold the sand in place and wind is constantly moving it from place to place.
Over the years most deserts have become bigger in size because the sand is getting blown over the neighbouring land thus making it infertile and devoid of vegetation. Large areas which were earlier under forests are deforested today and unless trees are replanted in these areas, the soil would bear the brunt of erosion.
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