SOIL FERTILITY

1
SOIL FERTILITY
2
Which soil profile is likely to be more fertile?
A
B
3
Soil Profiles

• Soil Profile (B) MORE FERTILE
• Black in color.
• Rich in organic matter in the form of humus.
• Less leaching and mineral rich soil.
• Found in grasslands which are semi-arid.
• Soil Profile (A) LESS FERTILE
• Gray in color, ashy appearance.
• Severely leached and highly acidic.
• South of the tundra regions of the Northern
  hemisphere.
• Typically found in the Boreal forest.

4
(No Transcript)
5
Soil Fertility and Precipitation

1. Heavily leached soils
2. Black prairie soil
3. Brown prairie soil
4. Lightly leached soil

2
4
3
1
6
Why are Tundra soils infertile?
Pg 92
7
Tundra soils are infertile because

• The subsoil is permanently frozen (permafrost).
• Plant roots cannot get water or grow downward.
• In the summer surface soil thaws, the soil
  beneath stays frozen, hence water cannot move
  downward.
• Surface soil is now
• Water logged
• Cold
• Free of air
• Therefore, material cannot decay and form humus,
  so there is no organic nutrients for vegetation.

8
Soil Erosion

• Soil erosion The process by which soil is worn
  away by wind, water, heat, cold, glaciers, loss
  of plants, etc.

9
Forests and Soil Erosion

• Forests prevent soil erosion through the use of
  their roots (roots hold the soil together).
• If the forest was removed, the soil would not
  have protection from wind, rain, or warm temps.

• Wind would blow the soil
• away.
• Rain would flood the soil.
• Warm temps. would heat
• up and dry out the soil.

• Forests also add decaying material to the soil,
  so if the forests were removed, the soil would
  have no nutrients.

10
Watersheds

• Watershed the area of land where all of the
  water drains to the same place.

11
Watersheds
12
Forests and Watersheds

• Forests maintain watersheds by
• Protecting and enhancing water supply.
• Help filtrate the water.
• Preventing the soil from drying out.
• Reduce flooding.
• Add nutrients.

13
Ecosystems
14
Latitude and Altitude
15
Depletion of the Ozone Layer