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Soil Chapter 5 Lesson 2 Pg What do you notice?…

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Presentation on theme: "Soil Chapter 5 Lesson 2 Pg What do you notice?…"— Presentation transcript:

1 Soil Chapter 5 Lesson 2 Pg. 240-246

2 What do you notice?…

3 What is soil? Soil is a mixture of bits or rock and once-living parts of plants and animals Soil covers most of the Earth ’ s landmasses Without soil, plants and animals would not be able to live on land Soil covers the ground in rain forests, grasslands, and deserts The soil in these places look different

4 Where would you find this soil? Desert Grassland Forest

5 Soil Horizons Each layer of the soil is called a soil horizon The A horizon (topsoil) contains the most nutrients. Humus is the part of the soil that is made of decayed organic materials This also holds water more easily The B horizon (subsoil) contains less humus and lots of fine particles of rock, such as the particles that make clay The C horizon is made mostly of larger pieces of weathered rock The soil horizons rest on solid, unweathered bedrock. You cannot grow plants on rocks!

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7 How is soil used? Each type of soil supports different plant and animal life Most of the US is covered by 3 types of soil: forest, desert, and grassland and prairie soil The soil in a forest has a thin layer of topsoil with little humus. Desert soil is sandy and does not hold much humus. The soil is rich in minerals and because it does not rain those minerals don ’ t get washed away The grasslands and prairies have soil that is rich in humus, which provides nutrients for crops Crops, such as corn, wheat, and rye are grown in Texas and North Dakota

8 How is soil used? Soil is a resource that can be used up, wasted, or spoiled It can be eroded by flowing water and wind Plant roots hold soil in place, so if plants are removed, more soil may erode The nutrients in soil are naturally removed by plants Plants use these nutrients to grow The nutrients are replaced when a plant dies and decays. If there are no more plants in an area, the soil cannot be replenished with nutrients Pollution can add harmful materials to the soil and it will be difficult to grow crops.  Pesticides, trash, and other chemicals add pollution to the soil

9 How is soil conserved? Fertilization: fertilizers containing one or more nutrients can be added to replace nutrients used by previous crops Crop Rotation: farmer can alternate the type of crops they plant from one year to the next. They choose crops that add nutrients that were removed the year before Strip Farming: Plant roots help prevent soil from being washed or blown away. Farmers plant grasses between rows of crops Individual Efforts: avoid polluting soil with trash and help clean the land Contour plowing: Farmers can slow the speed of water flowing down the hill. Farmers plow furrows across the slope Terracing: Flat shelves that are cut into a hillside. Crops are planted along each terrace Wind Breaks: farmers plant tall trees along the edges of farmland to slow the speed of wind across the ground Laws: Governments pass laws to stop the pollution of soil Education: you can help inform the value of soil and how to conserve it


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