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7th Grade Chapter 1 Lesson 3

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M
MRS.KDUNCAN

Soil is formed through the weathering of rocks and minerals, with its composition depending on the sizes of particles present. These particles include sand, silt, and clay, with soils being named based on their predominant constituent - sandy, silty, or clayey. Loam is an ideal soil mixture, containing balanced amounts of sand, silt, and clay along with humus, making it fertile for plant growth.

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7 th Grade Chapter 1 Lesson 3 Pgs. 16-20 For Student Use Only
Characteristics of Soil Soil is formed when different minerals and rocks are weathered. The composition of the soil depends on the sizes of mineral particles in the soil. Particles: Sand- gritty, course, large particles, allows air and water into the soil Silt- small, fine particles Clay- smallest particles
Characteristics of Soil Scientists name soils by what combination of sand, silt, and clay are found in the soil. Silty soils- contain a high weight percentage of silt Sandy soils- contain a high weight percentage of sand Clayey soils- contain a high weight percentage of clay
Characteristics of Soil Loam: Loam is a mixture of sand, silt, and clay. Healthy plants need a balance of all these soil types. Loam contains 3%-7% of humus Farmers want fertile loam to grow plants Sand helps water to drain, and clay and humus keep nutrients in soil for plants.
Characteristics of Soil Colors of soil: Soil can have different colors from yellow to red to dark brown. The color helps tell what nutrients and organic material is on the soil. Dark brown- more organic matter Reddish- have iron and clay
Characteristics of Soil pH of soil: Soil has pH and uses the pH scale. Soil can range from acidic, basic (alkaline), or neutral Acidic- lower pH 0-6 Basic- (alkaline)- higher pH 8-14 Neutral- middle pH 7 Soil can range from 3.5-11.0
Characteristics of Soil Plants and pH Some plants can grow in acidic or basic soil Most plants grow in soil around 7 pH (neutral)

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7th Grade Chapter 1 Lesson 3

  • 1. 7 th Grade Chapter 1 Lesson 3 Pgs. 16-20 For Student Use Only
  • 2. Characteristics of Soil Soil is formed when different minerals and rocks are weathered. The composition of the soil depends on the sizes of mineral particles in the soil. Particles: Sand- gritty, course, large particles, allows air and water into the soil Silt- small, fine particles Clay- smallest particles
  • 3. Characteristics of Soil Scientists name soils by what combination of sand, silt, and clay are found in the soil. Silty soils- contain a high weight percentage of silt Sandy soils- contain a high weight percentage of sand Clayey soils- contain a high weight percentage of clay
  • 4. Characteristics of Soil Loam: Loam is a mixture of sand, silt, and clay. Healthy plants need a balance of all these soil types. Loam contains 3%-7% of humus Farmers want fertile loam to grow plants Sand helps water to drain, and clay and humus keep nutrients in soil for plants.
  • 5. Characteristics of Soil Colors of soil: Soil can have different colors from yellow to red to dark brown. The color helps tell what nutrients and organic material is on the soil. Dark brown- more organic matter Reddish- have iron and clay
  • 6. Characteristics of Soil pH of soil: Soil has pH and uses the pH scale. Soil can range from acidic, basic (alkaline), or neutral Acidic- lower pH 0-6 Basic- (alkaline)- higher pH 8-14 Neutral- middle pH 7 Soil can range from 3.5-11.0
  • 7. Characteristics of Soil Plants and pH Some plants can grow in acidic or basic soil Most plants grow in soil around 7 pH (neutral)