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Published byBeatrix Paul Modified over 9 years ago
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Different types of soil Soil is made of four parts: 1) Sand 2) Silt 3)Clay 4)Humus
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Sand, Silt and Clay are inorganic. Sand is the largest particle in the soil. When you rub it, it feels rough. This is because it has sharp edges.
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Sand doesn’t hold many nutrients. Sand is good for drainage.
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Silt is a soil particle whose size is between sand and clay. Silt feels smooth and powdery. When wet it feels smooth but not sticky.
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Clay is the smallest of the particles. Clay is smooth when dry and stick when wet. Soils high in clay content are called heavy soils.
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Here is some red clay when its wet.
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Here is some clay we use to make pots.
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Clay can also hold lots of nutrients, but doesn’t let air and water through it well. Nutrients are food for living things.
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What is this? Clay
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What is this? Silt
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What is this? Sand
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If a particle of sand was the size of a basketball Sand
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Then silt would be the size of a baseball. Silt
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And clay would be the size of a golf ball. Clay
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Which is the biggest?
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So which is the biggest?
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Humus is organic matter. Organic means natural and made from living things. It is made of decayed or dead plants and animals. Humus contains the most nutrients.
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Soil is classified by the amount of sand, silt, clay, and humus it contains. This is sandy soil.
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Sandy soil has the largest pieces. It also has a lot of air spaces between the pieces.
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Sandy soils have good drainages but they do not hold water and nutrients well.
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This is clay soil.
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Clay soil is heavy. It has few spaces between the pieces so drainage is not good. It holds nutrients well but doesn’t allow water and air to pass through.
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This is Loam soil.
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Loam soil has a lot of organic matter. It has a good mixture of sand, silt, clay and humus. It has good drainage and plenty of nutrients.
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So which soil is the best for growing plants? A. Sandy Soil B. Clay Soil C. Loam Soil
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Plants need air, water, and nutrients from soil. Loam has all of these things so it is the best for growing plants.
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Some plants use humus for nutrients. Small animals eat the plants and bigger animals eat the small animals. Humus is an important part of the food chain.
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Homework: complete the handout with a partner. Fill in the blanks using page 27, 28 and 29
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