T18-1 Soil Science and Management, 4E
Chapter 18
Soil Conservation
T18-2 Soil Science and Management, 4E
Objectives
• List the effects of soil erosion• Describe how soil erosion occurs• List the types of water and wind
erosion• Calculate soil loss from water
erosion on a field• Describe ways to prevent erosion
T18-3 Soil Science and Management, 4E
Terms to Know• Cross-wing ridges• Cross–wind trap
strips• Ephemeral gullies• Filter strips• Gully erosion• Revised Universal
Soil Loss Equation (RUSLE)
• Rill erosion
• Saltation• Sheet erosion• Splash erosion• Surface creep• Suspension• Universal Soil Loss
Equation (USLE)• Wind Erosion
Equation (WEQ)
T18-4 Soil Science and Management, 4E
Erosion
• Cost of erosion
Figure 18-1
T18-5 Soil Science and Management, 4E
Erosion
Figure 18-2
T18-6 Soil Science and Management, 4E
How Water Erosion Occurs
• Texture and structure
• Slope
Figure 18-6
T18-7 Soil Science and Management, 4E
• Surface roughness
• Soil cover
• Types of water erosion
How Water Erosion Occurs
T18-8 Soil Science and Management, 4E
Predicting Soil Loss: The Universal Soil Loss Equation
• Tolerable soil loss
T18-9 Soil Science and Management, 4E
Figure 18-12
The Universal Soil Loss Equation
T18-10 Soil Science and Management, 4E
The Universal Soil Loss Equation
Figure 18-13
T18-11 Soil Science and Management, 4E
The Universal Soil Loss Equation
Figure 18-14
T18-12 Soil Science and Management, 4E
The Universal Soil Loss Equation
Figure 18-15
Figure 18-16
T18-13 Soil Science and Management, 4E
The Universal Soil Loss Equation
• Sample solution
• Applications of the USLE
• The Revised Universal Soil Loss Equation
T18-14 Soil Science and Management, 4E
Controlling Water Erosion
• Conservation tillage
Figure 18-17
T18-15 Soil Science and Management, 4E
Controlling Water Erosion
• Soil cover
Figure 18-18
T18-16 Soil Science and Management, 4E
Controlling Water Erosion
• Crop rotation
Figure 18-19
T18-17 Soil Science and Management, 4E
Controlling Water Erosion
• Grassed waterway• Contour tillage (See Figure 18-21)
Figure 18-21
T18-18 Soil Science and Management, 4E
Controlling Water Erosion
• Strip-cropping
• Improving organic matter
T18-19 Soil Science and Management, 4E
Controlling Water Erosion
• Terraces (See Figure 18-24)
• Filter strips
• Diversions
Figure 18-24
T18-20 Soil Science and Management, 4E
Wind Erosion
Figure 18-25
T18-21 Soil Science and Management, 4E
Wind Erosion
• Cause of wind erosion
Figure 18-26
T18-22 Soil Science and Management, 4E
Wind Erosion
• Effects of wind erosion
• Factors in wind erosion
• Preventing wind erosion
• Critical periods
T18-23 Soil Science and Management, 4E
Summary• Three fifths of soil lost to erosion washes away in
running water• Water/wind erosion:
– Strips topsoil– Reduces yields– Deposits sediments
• Two thirds of soil erosion from wind• Ways to control erosion:
– Grow vigorous crops– Maintain organic matter– Avoiding overtillage and compaction– Crop rotation– Contour tillage, strip cropping, and terraces
