SOILS ONE OF THE MOST IMPORTANT SUBSTANCES IN THE WORLD!

SOILS AGRONOMIST’S DEFINITION The loose cover of earth made of minerals (sand, silt and clay), water, air and organic matter; is capable of supporting plant growth.

How is soil formed? Try to picture the rocks that originally formed the outer surface of the earth’s crust. This the raw material of soil and is called parent material. Try to picture the rocks that originally formed the outer surface of the earth’s crust. This the raw material of soil and is called parent material.

What are the five factors of soil formation? Parent material Parent material Topography Topography Climate Climate Life – biological, animal & (human) Life – biological, animal & (human) Time - absolute Time - absolute - relative - relative

Parent material

Topography

Climate - weathering Mechanical weathering from wind Mechanical weathering from wind

Life

Time

How rapidly rocks break down depends on: Physical, chemical and biological forces Physical, chemical and biological forces The kinds of minerals the rock contains The kinds of minerals the rock contains

Rocks defined Rocks consists of any mineral or aggregate (clusters) of minerals that forms as a part of the earth. Rocks consists of any mineral or aggregate (clusters) of minerals that forms as a part of the earth.

Three categories of rocks: Igneous Igneous Sedimentary Sedimentary Metamorphic Metamorphic

Igneous Brought up from below in a molten condition Brought up from below in a molten condition Has no evidence of banding Has no evidence of banding All surfaces look the same All surfaces look the same

Igneous rock

Examples of igneous rocks Granite Granite

Another example of igneous rock Basalt Basalt

Another example of igneous rock Obsidian Obsidian

Sedimentary Rock Sedimentary rock is a result from weathered particles of rocks that have been deposited from suspension transported by wind, water or ice and is cementing together under pressure. Sedimentary rock is a result from weathered particles of rocks that have been deposited from suspension transported by wind, water or ice and is cementing together under pressure. Often forms in layers Often forms in layers

Sedimentary Rock

Examples of sedimentary Rock Limestone – CaCO3 Limestone – CaCO3

Another example of sedimentary rock Sandstone Sandstone

Another sedimentary rock conglomerate conglomerate

Another sedimentary rock Shale Shale

Metamorphic Rock Metamorphic rock is a secondary rock that may form from Igneous rock or sedimentary rock as a result of heat, pressure or chemical action. Metamorphic rock is a secondary rock that may form from Igneous rock or sedimentary rock as a result of heat, pressure or chemical action.

Metamorphic rock

Examples of metamorphic Rock quartzite quartzite

Another example of metamorphic rock marble marble

Another example of metamorphic rock slate slate

Another example of metamorphic rock schist schist

Another example of metamorphic rock gneiss gneiss

What types of rocks do you find in Connecticut? Eastern CT- mostly metamorphic rocks such as gneiss, schist and quartzite with some igneous rock such as granite. Eastern CT- mostly metamorphic rocks such as gneiss, schist and quartzite with some igneous rock such as granite. Central CT – is low land consisting of red sandstone. The hiss in this low area consists of igneous rock, such as basalt, which is also called trap rock. Central CT – is low land consisting of red sandstone. The hiss in this low area consists of igneous rock, such as basalt, which is also called trap rock. Northwestern CT – Sedimentary rocks such as limestone Northwestern CT – Sedimentary rocks such as limestone Western CT – Metamorphic rocks such as schist and quartzite. Western CT – Metamorphic rocks such as schist and quartzite.

How are complex rock surfaces broken down? Sudden changes in temperature causes rocks to expand or contract which causes rocks to crumble and flake. Sudden changes in temperature causes rocks to expand or contract which causes rocks to crumble and flake. Water finds its way into cracks and crevices. Water finds its way into cracks and crevices. Water in the cracks can change to ice and expand, causing the rock to break into smaller fragments. Water in the cracks can change to ice and expand, causing the rock to break into smaller fragments. As the rocks are reduced, minerals combine with water forming new compounds. As the rocks are reduced, minerals combine with water forming new compounds. Some minerals disolve and are washed away, while some like quartz and clay, become an important part of the soil. Some minerals disolve and are washed away, while some like quartz and clay, become an important part of the soil.

How can parent material be moved from one place to another? Glaciers Glaciers Gravity Gravity Water Water Wind Wind Each time particles are moved, they may be further broken down and sorted to size. Each time particles are moved, they may be further broken down and sorted to size.

Geological Classifications of soils are based on how the soil was deposited CT Geological Soil classifications Glacial till – A mix of gravel, sand, silt and clay that was deposited by ice with little or no water transportation. Glacial till – A mix of gravel, sand, silt and clay that was deposited by ice with little or no water transportation.

Stratified drift Rock materials sorted by waters from glaciers and left in layers as partially sorted. The finer particles, silt and clay, were generally carried off. Rock materials sorted by waters from glaciers and left in layers as partially sorted. The finer particles, silt and clay, were generally carried off.

Alluvium Materials moved by waters and later deposited along stream beds. This is rich soil, great for farming! Materials moved by waters and later deposited along stream beds. This is rich soil, great for farming!

Loess Mostly transported by wind during dry weather periods right after the melting of the glacial ice. Mostly transported by wind during dry weather periods right after the melting of the glacial ice.

Glaciolacustrine Very fine sand, silt and clay picked up by glacial action to glacial lakes. (layered with varied thickness) Very fine sand, silt and clay picked up by glacial action to glacial lakes. (layered with varied thickness)

Organic Soils Plant material accumulated in shallow waters. As generations of plants died they filled in saucer like depressions called peat (if identifiable) or muck (if impossible to identify. Plant material accumulated in shallow waters. As generations of plants died they filled in saucer like depressions called peat (if identifiable) or muck (if impossible to identify.