1. Soil Profile

2. Soil Profile
Because the particles that make up soil are deposited at different times and from different places, the soil forms in layers, which we call HORIZONS

3. O Horizon
- Organic material that gathers on top of the soil layers

4. Composed of HUMUS (decayed organic matter)
O Horizon
A Horizon
Also called TOPSOIL
Composed of HUMUS (decayed organic matter)
Fine texture
Ideally should be at least 18 cm deep

5. B Horizon Also called SUBSOIL
O Horizon
A Horizon
B Horizon
Also called SUBSOIL
Made up of an accumulation of finely weathered material that have washed down from the A Horizon
Nutrients that accumulate here can be “called back” to the A Horizon when needed (drought, etc.), so the B horizon acts as a storehouse of nutrients for the A horizon.

6. Coarse, less weathered material
O Horizon
A Horizon
B Horizon
C Horizon
Also called REGOLITH
Coarse, less weathered material
Under very dry conditions this horizon may provide minerals to the soil layers above
This horizon is too deep to be reached by most root systems , so it really has no effect on soil fertility

7. The solid foundation on which all the other layers sit
O Horizon
A Horizon
B Horizon
C Horizon
D Horizon
Also called BEDROCK
The solid foundation on which all the other layers sit
Has nothing to do with soil fertility

8. SALINIZATION (CALCIFICATION)
Leaching
- The process by which mineral salts in the upper horizons are moved downward
SALINIZATION (CALCIFICATION)
- The accumulation of soil salts in the topsoil as heat evaporates the moisture out of the soil
O Horizon
A Horizon
B Horizon
C Horizon
D Horizon
CAPILLARY ACTION
Occurs in dry areas
As surface water evaporates it is replaced by water from further down in the soil profile.
In this manner water and nutrients can move upward.