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Soil and the Soil Ecosystem. Soil Characteristics. Profiles Texture Classes. Soil Profiles. A vertical slice through the different horizons Horizons- horizontal layers in soil. O Horizon. Dead organic matter (detritus) Primary energy source for the soil ecosystem
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Soil Characteristics • Profiles • Texture • Classes
Soil Profiles • A vertical slice through the different horizons • Horizons- horizontal layers in soil
O Horizon • Dead organic matter (detritus) • Primary energy source for the soil ecosystem • Humus- bottom of O, advanced decomposition
A Horizon • Topsoil- mixture of mineral soil and humus • Roots present • Usually dark
E Horizon • Eluviation- leaching minerals downward by water movement • Pale in color
B Horizon • Minerals from A and E deposited here • High in iron, aluminum, calcium, and others • Subsoil • High clay content, reddish/ yellow
C Horizon • Parent mineral material • Weathered rock, glacial deposits, volcanic ash
Soil Texture • Small Stones • Sand • Silt • Clay
Particle Size • Sand- 2.0 - 0.02 mm • Silt- 0.02 – 0.002 mm • Clay- <0.002 mm
Loam • Common proportion • 40% sand • 40% silt • 20% clay • Triangle
Properties • Larger particles have larger spaces separating them • Smaller particles have more surface area relative to volume • Nutrient ions and water molecules cling to surfaces
Soil Classes • Taxonomy of soil • Four major classes • Mollisols • Oxisols • Alfisols • Aridisols
Mollisols • Fertile, dark soil • Temperate grassland biome • Good agriculture • Midwest US, Ukraine, Russia, Mongolia, Argentina • Deep A horizon, rich in topsoil
Oxisols • Tropical rain forest • Iron and aluminum oxides in B horizon • Little O horizon • Limited fertility for agriculture • Minerals leached down by rainfall
Alfisols • Widespread, moderately weathered forest soil • Well-developed O, A, E, B • Moist, temperate forest biome • Suitable for agriculture, need organic matter/fertilizer added
Aridisols • Drylands and deserts • Unstructured vertically • Light colored • Irrigation leads to salinization
Article: Windsor Soils • What are Windsor soils? • Why is this type of soil important to CT? • What specific crops benefit from Windsor soils? • How are Windsor soils formed? • Describe the Windsor soil profile.