Soil and Its Formation

Soil and Its Formation

What is usually the maximum depth (thickness) of soil?______
Why is the quality and amount of soil so crucial?______
______
What is one theory for the disappearance of civilization on Easter Island?______
______
Components of Soil

How can layers in the soil be identified?______
______
What type of matter is there less of, the deeper the soil? ______
a)The upper layer is known as the ______and it acts like a blanket, limiting ______and reducing ______by ______.

b)The next layer down is called the ______which is composed of small particles of ______and decaying ______and ______matter. This is called ______. This layer is usually rich in ______and ______. Its colour is often ______. Also in the topsoil are ____ and ______in the spaces between rock particles.

Why are these spaces important?______
______

If there is very little oxygen, dead plant material ______slowly and can build up into a material called ______.

c)Below the topsoil is the ______, which contains more ______mixed with only small amounts of ______. This layer is ______in colour because of ______
______

d)Beneath the soil lies a layer of ______which marks the ______

Formation of Soil
Soil begins as ______. Through a process called ______, soil is broken down into smaller particles. Small plants will begin to grow and add organic materials to enrich the ______
How long can it take for soil to form? ______
In Eastern Canada (including Ontario), what was most soil formed from? ______
______
Soil Horizons Soil layers are often called “horizons” and given the labels O, A, B, C.
Label the diagram below with its name and a brief description of its composition.

Layer Name Description

Water Beneath the Soil

Water flowing above ground is called ______(e.g. lakes, ponds, rivers etc.) Once in the soil or rock it is called ______. Gravity pulling waterdownward through the soil is called ______. The rate of percolation will increase with the ______of ______between soil particles. The water percolating downward eventually reaches a layer that is ______with water called the ______. Underneath this is a layer that water cannot flow through – usually ______or dense ______which the water cannot ______through. As water seeps downward, it ______organic matter and ______from the soil and carries them deeper. This is called ______.

Why can leaching be a serious problem? ______
7. Soil pH
Soils can be ______, ______or ______.
What natural processes determine the pH of soil? ______
______
What human activities can affect the acidity of soils? ______
______
What types of plants grow best in acidic (low pH) soils?______
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What types of plants grow best in alkaline (high pH) soils? ______
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