Changes
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Changes
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Most soil is made up of rock. Rocks are worn down into smaller pieces by rain, wind, and ice. Gravel is a big type of sediment (worn down rock). Sand is a second kind of sediment. Silt is a third kind, and feels like powder. Clay is the fourth kind, and is very tiny.
Soil changes over time. Sometimes it erodes. That means that part of it gets washed away by rain, or blown away by wind. When it erodes, you can see the roots of plants.
Picture used with permission from Pics4Learning
Sometimes animals eat all the grass or plants in a field. When this happens, there are no plant roots to hold the soil together, and it can easily blow away.
Pollution can also damage soil, because it destroys the nutrients. This affects the plants and trees, because they become weak and eventually die. Farmers have to be careful about the pesticides (bug-killers and weed-killers) they use to be sure that it doesn’t affect the soil.
Picture by Dominique |
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