Introduction To Soils

1
Introduction To Soils

• Original Power Point Created by Darrin Holle
• Modified by Georgia Agricultural Education
  Curriculum Office
• June 2002

2
Soil and Its Importance

• Provides basic life needs
• Food and Shelter
• Very limited resource

3
Main Ideas in Land Evaluation

• 1. Texture
• 2. Depth
• 3. Slope
• 4. Erosion

4
1. Texture

• Affects almost all properties of the soil
• The amount of sand, silt and clay in a soil
• Sandlargest, then silt, then clay
• Determine by ribboning the soil

5
1. Texture

• Sand is looser and gritty
• Silt feels floury
• Clay is sticky

6
1. How to determine Texture

• COURSENO BALL
• MODERATLY COURSE 1 and gritty
• MEDIUM 1 and smooth
• MODERATELY FINE 1-2
• FINE 2

7
Depth

• Total thickness of material available for plant
  growth
• Plants obtain water, nutrients and support from
  the root zone
• Total Depth is determined from the point where
  the roots stop

8
Depth

• DEEP40
• MODERATLEY DEEP 20-40
• SHALLOW 10-20
• VERY SHALLOW -10

9
Slope

• Slope refers to the steepness of the land surface
• Affects soil use and management
• As slope increases agriculture suitability
  decreases

10
How to measure Slope

• Measured in percent
• Rise or fall over 100 feet

11
How to measure Slope

• NEARLY LEVEL 0-1
• GENTLY SLOPING 1-3
• MODERATELY SLOPING 3-5
• STRONGLY SLOPING 5-8
• STEEP 8-15
• VERY STEEP 15

12
Erosion

• Causes loss of soil by water and wind
• If one knows history of land can then do
  something to prevent more losses

13
Erosion Calculation

• One will be given original topsoil
• To find current topsoil drag knife through top
  layer until it stops. This is the topsoil

14
Erosion Calculation

• Divide the current topsoil by the original to
  give you what percent is left
• Then subtract that from 100 and that gives you
  amount of erosion.

15
Erosion Levels

• NONE TO SLIGHT 0-25
• MODERATE 25-75
• SEVERE 75 with crossable gullies
• VERY SEVERE 75 with uncrossable gullies