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Soil and the Ecosystem. Why is soil important?. Soil determines which plants can grow in an area. Plants are the foundation of the food chain and determines what other animals can live in an area. What is soil?.
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Why is soil important? • Soil determines which plants can grow in an area. • Plants are the foundation of the food chain and determines what other animals can live in an area
What is soil? • Soil is a mixture of rock, minerals, clay, sand, silt, and decayed organic material (decomposed plant and animal)
How is soil formed? • Soil is formed from the weathering or breaking down of rock
What is a soil profile? • Soil forms in layers called horizons • These layers make up the soil profile • A good soil profile includes three layers –topsoil, subsoil, and parent material above a layer of bedrock
What are the horizons of soil? • Go to the website: http://school.discoveryeducation.com/schooladventures/Soil Describe the following layers – topsoil, subsoil, parent material, and bedrock
Soil Composition • Made up of rock, air, water, minerals, sand, silt, clay and humus • Humus is the decayed organic material (plant/animal) • Different areas have different amounts of sand, silt, clay, and humus. These combinations makes different types of soil
Composting • The process of piling up organic material for decomposition that can be used as a soil amendment or as a medium to grow plants. • Compost is another name for humus.
Soil Types • Loam – equal amounts of sand, silt, and clay • Sandy Clay Loam – more sand and clay than silt • Silt Loam – more silt than sand or clay • Clay – more clay than sand or silt
Sand, Silt, or Clay • Go to the website: http://school.discoveryeducation.com/schooladventures/soil/name_soil.html • Describe sand, silt, and clay
Soil Texture • Depends on the size of the individual particle of soil • The size of the soil affects the amount of water that can be absorbed for use by plants and animals • Any particle larger than 2mm is considered gravel
Permeability • Ability of water to move through the soil • Water moves through sand quicker than silt of clay • Bigger soil particles, the faster the water will move because the spaces between the particles are bigger
pH of soil • Most soils have a pH of 4-10 • Depends on the amount of decayed plants and animals • Plants grow best when the pH is between 5 and 7