Soil Erosion: Causes, Control & Estimation

AGME 1613 - Fundamentals of Agricultural Systems Technology

Photos courtesy of NRCS of USDA

Objectives

• Describe the two causes of soil erosion

• Describe the types of soil erosion by water

• Estimate the rate (tons/ac) of soil erosion using the RUSLE

• Describe common erosion control practices

Soil Erosion

• The detachment and movement of soil particles by the erosive forces of wind or water.

USDA estimates 70% of Soil Lost by Erosion is from Agricultural Land

Soil Erosion by Wind

Factors Affecting:Soil erodibility

Climate

Soil roughness

Field length

Vegetation

Soil Erosion by Water

Raindrop Sheet Interrill Erosion

Rill Erosion Gully Erosion

Raindrop Erosion

Estimating Soil Erosion

• Revised Universal Soil loss Equation (RUSLE)

A = R x K x L x S x C x P

A = Average annual soil loss (tons/ac/year)R = Rainfall factor (approximately 275 for

Fayetteville)K = Soil erodibility factor (p. 221)L = Slope length factor (p. 222)S = Slope gradient factor (p. 222)C = Cropping management factor (p. 223)P = Erosion control practice factor (p. 223)

Example RUSLE Problem

• Estimate the annual erosion for a field having the following characteristics:– Rainfall factor = 275– Continuous small grain – Silt loam soil

• 1% organic matter• 6% slope with a length of 400-ft.

– Farmed up and down the slope– Moderate residue (worked under)

Example RUSLE Problem

• Rainfall factor = 275• Continuous small grain• Silt loam soil

– 2% organic matter– 6% slope with a length of

400-ft.

• Farmed up and down the slope

• Moderate residue (worked under)

A = R x K x LS x CP

Decreasing Erosion by Changing Cropping Practices

• Assume same situation as before, except:– We plant on the contour

• Assume same situation as before, except:– We plant into residue of previous crop (ROS)

• Assume same situation as before, except:– We plant on the contour, and – We plant into residue of previous crop (ROS)

Water Erosion Prediction Project(WEPP)

Erosion Control Practices

• No-Till Farming

• Minimum Till Farming

• Contour Farming

• Strip Cropping

• Terracing

• Grass Waterways

No-Till and Minimum Till Farming

• Leave plant residue on soil surface.

• Reduce erosion by absorbing energy from falling raindrops, increasing water infiltration, and reducing run-off.– No-Till– Minimum Till

Contour Farming

Minimum Tillage/Contour Farming

Strip Cropping

Contour and Strip-Cropping

Terraces

Terrace after Storm

Drop Inlet Terrace

Grass Waterways