🌍 Soil Horizons and Layers
Explore the structure and composition of soil profiles in Ontario's environment. Soil is made up of distinct layers called horizons, each with different characteristics and roles. Understanding soil horizons helps us recognize how plants get nutrients, how water moves through soil, and why topsoil is precious for agriculture and ecosystems. **What you'll learn:** - Identify the four main soil horizons and their characteristics - Understand what materials and organisms are found in each layer - Explain why the A horizon is critical for plant growth - Recognize how soil forms and develops over time
Questions in this quiz
Answers hidden — play to find out.
- Question 1
Which soil horizon is known as the O horizon and what does it primarily contain?
- Question 2
Why is the A horizon sometimes called the 'topsoil' and considered the most important layer for farming?
- Question 3
The B horizon is the layer directly below the A horizon and is called the subsoil.
- Question 4
What is the main characteristic that helps you identify the C horizon in a soil profile?
- Question 5
In order from top to bottom, what is the correct sequence of soil horizons?
- Question 6
The B horizon contains more nutrients and organic matter than the A horizon.
- Question 7
Which of the following organisms and materials would you most likely find in the O horizon?
- Question 8
Why do plant roots grow most actively in the A horizon rather than deeper layers?
- Question 9
The O horizon is always present in every soil profile in Ontario.
- Question 10
Which horizon would you expect to be lighter in color (more tan or yellow) compared to the darker A horizon?
- Question 11
What role do decomposers (like bacteria and fungi) primarily play in the O and A horizons?
- Question 12
Water moves more slowly through the B horizon than through the A horizon because the B horizon contains more clay.
- Question 13
How long does it typically take for a significant layer of new topsoil (A horizon) to form in nature?
- Question 14
Which of the following best describes how the horizons of a soil profile develop?
- Question 15
Erosion of the A horizon is not a concern because new topsoil will quickly replace it from the B horizon below.