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What Is Soil?. Soil is the layer of rock and mineral fragments along with organic matter, water and air that supports the growth of plants. The four components of soil: Decomposed rock Humus Air Water. What is Dirt?. Dirt is what gets on your clothes and into your house.
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What Is Soil? Soil is the layer of rock and mineral fragments along with organic matter, water and air that supports the growth of plants. The four components of soil: Decomposed rock Humus Air Water
What is Dirt? Dirt is what gets on your clothes and into your house
Controls on Soil Formation • Parent material – Bedrock vs. Unconsolidated • Time – longer time, more soil • Climate – temperature and precipitation • More plants and animals = more organic matter • Poorly developed soils on steep slopes
Soil Texture and Structure Point A: 10% silt 40% clay 50% sand Clay loam has no single particle size percentage that dominates!
Controls of Soil Formation If the parent material is bedrock, then we get residual soils On unconsolidated sediments, we get transported soils
Soil composition -Soil forms in layers -Larger materials are found on the bottom How quickly is soil formed? -It may take several hundred years for 1cm to form
Soil profile A vertical column showing the sequence of layers of particles in the soil
Soil Horizons -A distinct layer or zone within a profile -There are four major zones (O, A, B, C) O zone -Leaf litter, high decomposition A Zone -High organic matter -Generally the darkest in color -High humus content B Zone -Less developed -Lighter in color -Zone of accumulation (highly soluble mineral build-up) -Red or brown in color -Clay accumulated (Hard pan formation) C Zone -Contains weather parent material
Soil Horizons O zone -Leaf litter, high decomposition A Zone -High organic matter -Generally the darkest in color -High humus content B Zone -Less developed -Lighter in color -Zone of accumulation (highly soluble mineral build-up) -Red or brown in color -Clay accumulated (Hard pan formation) C Zone -Contains weather parent material
Eroded channels ranging in size from rivulets to small gullies caused mainly by runoff waters rather than raindrop dislocation.
Gully erosion in Tanzania. What is the main factor for it’s cause?