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Soils

Overview

When you look at soil, you may think it is all just “dirt.” If you look more closely, however, you will see that different soils have different key attributes. In the Piedmont region of Georgia, soil is predominantly made of clay and granite minerals. The “red clay” that gives this region's dirt a reddish color is filled with iron that has been broken down over time. The clay in the soil holds important nutrients that get lost in the wind and rain when exposed without vegetative coverage. There are other types of soil, composed of different amounts of sand, stone, clay, and organic matter. All soil however is made up of water, air, and organic matter, such as broken down leaves, in which microscopic organisms and earthworms live.

Main Concept

Soil is a natural substance made of minerals, water, air, gasses, and decaying plants and animals. It is the surface of the land upon which we live, farm, and build. Soil performs many vital functions to sustain life, such as growing food and providing a habitat for animals, insects, and microorganisms, like bacteria and fungi. Soils are also major recyclers in our ecosystems, breaking down organic matter and reusing its nutrients. Based on the location of a soil, it will differ in texture, minerals, and density, and how water is able to pass through it. Soils purify and hold much of the water in our ecosystems. Not only do they naturally filter water before it returns to lakes, rivers, and streams, but soils are vital for flood control and plant growth.


Definitions


Engineered Soil: Soils made from specific ratios of sand, silt, clay, and organic components such as compost or leaves. They are installed to help improve infiltration in a specific location.

Erosion: Gradual destruction of something by wind, water, or other natural agents.

Permeability: Degree to which water or another liquid is able to flow through a material.


Porosity: Number of gaps in material relative to its size.
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Runoff: Water on land that eventually reaches water bodies, often carrying dissolved materials such as sediment.
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Sediment: Loose sand, clay, or soil material deposited by wind, water, or glaciers.
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Key Questions

  1. How does soil function?
  2. What are the soil layers?
  3. What are the different properties of soil?
  4. How does water penetrate these layers differently?
  5. What is engineered soil?
  6. What are the benefits to the environment?
Launch Soil Activities