Geography 1100 Chapter Notes - Chapter 11: Gravity Gradiometry, Surface Tension, Permanent Wilting Point
3 Jun 2015
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Document Summary
Soil upon which life depends is only 30 centimeters deep (the topsoil) Soil is constantly being formed by the physical and chemical decomposition (weathering) of rock material and decay of organic matter. As it is being formed, it is also being eroded by wind or water. Normally, rate of soil formation is greater than rate of soil decay. When land is cleared of vegetation, process of erosion is accelerated. Erosion rate > formation = topsoil thinning. Once topsoil is gone, the renewable resource (soil) has been turned into a non- renewable asset and cannot be reversed. The recent increase in demand for food has increased the demand for more farms. This forces farms to move into different areas (sometimes on slopes) and farmers have to work the fields more intensively while providing less care. Pressure of growing population is having destructive effects on the tropical rain forests. Major cause of this is the clearing of land for crops.
