conserving land and soil
Terms
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- three uses that change the land are:
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1. agriculture
2. mining
3. development - agriculture
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Land is the source of most of the food that people eat. Not all land is used to grow food for people.
1. grow food for livestock
2. grow cotton for clothing - mining
- The removal of nonrenewable resources from the land.
- strip mining
- removing a strip of land to obtain minerals and then replacing the strip.
- underground mining
- for resources located deep underground you dig a tunnel or a shaft. The minerals are carried up through the shafts.
- development
- the construction of buildings, roads, bridges, dams, and other structures.
- Why isn't all land suitable for farming?
- It is too dry, too weet, too salty, or too mountainous.
- Fertile soil is made up of several layers of what?
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1. litter
2. topsoil
3. subsoil
4. bedrock - litter
- the very top layer of dead leaves and grass
- topsoil
- a mixture of rock fragments, nutrients, water, air, and decaying animal and plant matter
- subsoil
- contains rock fragments, water, and air, but less animal and plant matter than topsoil.
- bedrock
- all soil begins this way. this is the rock that makes up the Earth's crust.
- What breaks apart bedrock?
- freezing and thawing. Plant roots, acids in rainwater and chemicals released by lichens. Animals such as earthworms and moles.
- What is the first step in the process of soil creation?
- breakdown of the wastes and remains of living things.
- In which layer are most plant roots located?
- topsoil
- What do roots absorb in the topsoil area?
- water and nutrients