Soils form slowly. When different forces act on them, their characteristics change.
This is a soil profile. Describe what you see. Are there changes in the soil profile?
If so, what are they? Those changes, or layers, are called Horizons.
What is the gray, powder-like substance at Horizon 3C3? What do you think it might be?
The fine-gray powder was deposited in this stream bed approximately 150-250 years ago over a period of 100 years. What do you think it is?
It’s ash from forest fires. How did these forest fires last almost a hundred years?
Slash and Burn Agriculture. The results of some of that practice of burning down forests to make room for farms was deposited in this stream bed.
Now let’s look lower: What are the nodules at Horizon 4C4? What is this horizon’s story?
The nodules below that horizon were deposited in this stream bed about 250-350 years ago. They are clam and oyster shells? How did they get there?
The people indigenous to this geographic regions caught clams, oysters, and fish in this region. These shells were what they left behind.
The soil in this stream bed is formed and changed by these factors.
The parent material of this soil is partially formed of the ash from the forest fires.
The biota or living organisms affected this soil’s formation by depositing the ash and also the shells from other living organisms into the soil.
The topography of the soil’s location, a stream bed, affected how the materials were deposited and how they remain as part of this soil profile. This is just one of the super cool lessons we discuss during the workshop.