The document discusses soil and its properties. It is defined as the thin layer of material on Earth's surface where plants grow roots. Soil is made up of weathered rocks and decayed organic matter. It then describes the different soil horizons from O horizon at the surface to the B horizon below consisting of subsoil and the C horizon of bedrock. The factors that influence soil formation such as parent material, climate, topography, and biology are also mentioned. Different types of soils like sandy, clay, silt, loamy, peat, and chalky soils and their characteristics are defined. Key properties of soil including texture, structure, chemistry, color and classification systems are outlined. The role of soil in ecosystems

2. What is
Thin layer of material on the Earth’s
surface where plants have their
roots.
Made up of weathered rocks and
decayed plant and animal matter.

5. 1. O HORIZON
•The top layer of soil
•Made up of living and
decomposed materials (leaves,
plants, and bugs)
•It is very thin and is usually pretty
dark
•It is called ground level

6. 2. A HORIZON
•The layer that we call “
topsoil”
•It is made up of minerals and
decomposed organic matter
•Very dark in color
• many plants roots grow in

7. HORIZON
•The layer that we called
“subsoil”
•It has clay and mineral
deposits and less organic
materials
•Lighter in color than the

8. HORIZON
•The layer that we call
“bedrock”
•It is made up of slightly
unbroken rock and only a little
bit of organic material is found
•Plant roots are not found in

13. Parent
Material Climate
Time Topography
Biological
Factors

15. SANDY SOIL
•Large particles
•Dry and gritty to touch
•Less water retention
•Warm and airy
•Easily crumbles
through the fingers
•Ideal for crops like:
watermelon, peanuts
and peaches

16. CLAY SOIL
•Fine particles
•Smooth when dry,
sticky when wet
•Retains water
•Rich in nutrients
•Ideal for plants like:
leafy vegetables,
tomatoes, and peas

17. SILTY SOIL
•Tiny particles
•Slippery when wet
•Extremely fertile
•Retains water
•Ideal for crops
like: all vegetables
and fruits

18. LOAMY SOIL
•Retains water and
nutrients
•Easy to work with
•Ideal for crops like:
tomatoes, potatoes,
carrots
•Fertile
•Well-drained

19. PEAT SOIL
•Dark brown in colour
•Soft and spongy to
touch
•Contains acidic water,
not fertile
•Improves soil
buffering, mixed in soil
to improve structure
•Ideal for plants like:
Moss, shrubs and

20. CHALKY SOIL
•Light in colour
•Lime rich soil
•Poor in nutrients
•Free-draining
•Severely dry in
summers
•Ideal for plants like:
honeysuckle, rosa and
germanium

22. 1. Soil Texture
 Soil description of the relative
proportions of sand, silt and clay
 Large grains and pore spaces of
sandy soils mean that they drain
rapidly and holds little nutrients for
plants.
 Clay soils are easily waterlogged,
which prevents the movement of
oxygen in plants.

23. 2. Soil Structure
 Refers to how the soil particles are
arranged relative to each other.
 Soil particles tend to group
themselves into blocks called
“peds.”
 Peds are important for increasing
stability against erosion and in
maintaining porosity, improving
fertility and water movement.

24. 3. Soil Chemistry
 Study of chemical characteristics
of soil
 The terms alkaline and acid refer
to the pH (Potential Hydrogen) of
your soil.
 pH – measure of the relative
amounts of H+ and OH- in a
solution

25. 4. Soil Color
 Is the most obvious and easily
determined soil characteristic.
 Is primarily influenced by soil
mineralogy. Many soils are due to
various iron minerals.

26. Separation of soil into classes or
groups each having similar
characteristics and behavior

27. Genetic classification of soils
according to the US Comprehensive
Soil Classification System

28. The Role of Soil in
Ecosystems
and
The Effects of Soil
Erosion to Man