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Soil. “More than just dirt”. W hat can bring this air and water in the soil?. Soil Profile. “O” Horizon. Organic layer Made up of decayed plants and animals (humus) “untouched” soil. “A” Horizon. “topsoil” Organic matter accumulates
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Soil “More than just dirt”
“O” Horizon • Organic layer • Made up of decayed plants and animals (humus) • “untouched” soil
“A” Horizon • “topsoil” • Organic matter accumulates • Provides the best environment for growth of plant roots and other life • Generally thick layer • Seeds germinate
“B” Horizon • “subsoil” • “zone of accumulation” • Lower organic matter than topsoil • Section of the soil profile where most plant roots grow • Fine particles • Contains clay and mineral deposits
“C” Horizon • Also known as “regolith” • Consists of slightly broken up bedrock • Soil layer not touched • Parent material • Un-weathered • Little to no sign of soil formation
“R” Horizon • Also known as “bedrock” • Foundation of the soil profile
Grain size Soil Texture • Sand • Silt • Clay
Sand • Only one visible with the “naked eye” • Gritty (texture) http://www.youtube.com/watch?v=knrmCbctGEA&feature=related
Silt • Smaller than sand • Powdery texture • Doesn’t hold together well when wet
Clay • Smallest soil particle • Holds water well • Fine texture (feels smooth and wet) • Sticky