1. All About
Soil
All About Soil
4.7A

2. Soil can basically be separated into 5 main parts:
Humus
Clay
Silt
Sand
Gravel

3. Humus: A dark, moist soil composed of bits of dead, rotting insects, animals, leaves, roots, sticks, and food.  Humus adds nutrients to the soil which plants need to grow and live.

4. Clay: A soil that holds water. When wet, clay feels slippery and slimy
Clay: A soil that holds water.  When wet, clay feels slippery and slimy.  It is made of particles that are smaller than millimeters.

5. Silt: Soil that looks like fine grains or tiny pieces of rock
Silt: Soil that looks like fine grains or tiny pieces of rock.  Particles classified as silt measure from millimeters to millimeters.

6. Sand: Soil that is coarse and drains quickly
Sand: Soil that is coarse and drains quickly.  Sand particles measure from about millimeters to 2.00 millimeters.

7. Gravel: Visible rock particles, sometimes referred to as pebbles.

8. Soil Profiles A soil profile is a view of a cross section of soil.
Most living material exists in the top section, or topsoil.
Plant roots often extend into the second layer, called the subsoil.
The bottom two layers consist mostly of rock.

9. Characteristics of Soil Horizons
0 Horizon-located on surface, mostly O.M. (organic materials)
A Horizon-Called Topsoil, good amounts of O.M. and minerals.
B Horizon- Known as Subsoil, Less O.M.
C Horizon- Mostly parent material, does little for plant growth.

10. Soil Texture
Soil texture is the relative sizes of the different soil particles.

11. Major Soil Texture Classes
Sand is the largest particle.
Silt is a medium-sized particle.
Clay is the smallest particle in size.

12. Characteristics of a Sandy Soil

13. Characteristics of a Silty Soil

14. Characteristics of a Clay Soil

15. Soil Structure
Sand, silt and clay particles combine with one anther to form cluster called aggregates.
The way in which aggregates or clusters are arranged is referred to as soil structure.

16. Soil Structure Categories

18. Modified from a presentation by Carrie Nagle, Mecklenberg Public Schools.