T18-1 Soil Science and Management, 4E

Chapter 18Soil 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