Soil and the Soil Ecosystem Soil Characteristics l

Soil Characteristics l Profiles l Texture l Classes

Soil Profiles l. A vertical slice through the different horizons l Horizons- horizontal layers

O Horizon l Dead organic matter (detritus) l Primary energy source for the soil

A Horizon l Topsoil- mixture of mineral soil and humus l Roots present l

E Horizon l Eluviation- leaching minerals downward by water movement l Pale in color

B Horizon l Minerals from A and E deposited here l High in iron,

C Horizon l Parent mineral material l Weathered rock, glacial deposits, volcanic ash

Soil Texture l Small l Sand l Silt l Clay Stones

Particle Size l Sand- 2. 0 - 0. 02 mm l Silt- 0. 02

Loam l Common proportion l 40% sand l 40% silt l 20% clay l

Properties l Larger particles have larger spaces separating them l Smaller particles have more

Soil Classes l Taxonomy of soil l Four major classes l. Mollisols l. Oxisols

Mollisols l Fertile, dark soil l Temperate grassland biome l Good agriculture l Midwest

Oxisols l Tropical rain forest l Iron and aluminum oxides in B horizon l

Alfisols l Widespread, moderately weathered forest soil l Well-developed O, A, E, B l

Aridisols l Drylands and deserts l Unstructured vertically l Light colored l Irrigation leads

Article: Windsor Soils l What are Windsor soils? l Why is this type of

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Soil and the Soil Ecosystem

Soil Characteristics l Profiles l Texture l Classes

Soil Profiles l. A vertical slice through the different horizons l Horizons- horizontal layers in soil

O Horizon l Dead organic matter (detritus) l Primary energy source for the soil ecosystem l Humus- bottom of O, advanced decomposition

A Horizon l Topsoil- mixture of mineral soil and humus l Roots present l Usually dark

E Horizon l Eluviation- leaching minerals downward by water movement l Pale in color

B Horizon l Minerals from A and E deposited here l High in iron, aluminum, calcium, and others l Subsoil l High clay content, reddish/ yellow

C Horizon l Parent mineral material l Weathered rock, glacial deposits, volcanic ash

Soil Texture l Small l Sand l Silt l Clay Stones

Particle Size l Sand- 2. 0 - 0. 02 mm l Silt- 0. 02 – 0. 002 mm l Clay- <0. 002 mm

Loam l Common proportion l 40% sand l 40% silt l 20% clay l Triangle

Properties l Larger particles have larger spaces separating them l Smaller particles have more surface area relative to volume l Nutrient ions and water molecules cling to surfaces

Soil Classes l Taxonomy of soil l Four major classes l. Mollisols l. Oxisols l. Alfisols l. Aridisols

Mollisols l Fertile, dark soil l Temperate grassland biome l Good agriculture l Midwest US, Ukraine, Russia, Mongolia, Argentina l Deep A horizon, rich in topsoil

Oxisols l Tropical rain forest l Iron and aluminum oxides in B horizon l Little O horizon l Limited fertility for agriculture l Minerals leached down by rainfall

Alfisols l Widespread, moderately weathered forest soil l Well-developed O, A, E, B l Moist, temperate forest biome l Suitable for agriculture, need organic matter/fertilizer added

Aridisols l Drylands and deserts l Unstructured vertically l Light colored l Irrigation leads to salinization

Article: Windsor Soils l What are Windsor soils? l Why is this type of soil important to CT? l What specific crops benefit from Windsor soils? l How are Windsor soils formed? l Describe the Windsor soil profile.