TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Geography > Soil Erosion and acid rain
Acid rain
- Extra acid in the rain is formed in the air by coal fired power stations which give out sulphur dioxide and nitrogen dioxide. These gases rise and are converted into nitric acid and sulphuric acid when they combine with rain water or are carried by prevailing winds and are deposited on the Earth's surface (dry deposition)
- Acid rain can also be deposited after a few days as rain (wet deposition).
- Acid rain increases the acidity of lakes, killing fish and plant life and increases the acidity of soils limiting the number of crops which can be grown. Important nutrients (calcium and potassium) get leached away, damaging forests because aluminium (a harmful substance) replaces the nutrients. Water supplies get more acidic and can be a health hazard and buildings can get eroded away.
Soil Erosion
- Deforestation causes soil erosion as no more humus is added to the soil, and roots which bind together soil is lost leaving the soil exposed to wind which picks up the fine material and rain which washes it away. When this happens, bare rock and gullies are left. Soil erosion is caused by overgrazing, mining, over-cultivation and irrigation without adequate drainage which causes water logging.
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