Soil Erosion: Causes, Control & Estimation AGME 1613 - Fundamentals of Agricultural Systems Technology Photos courtesy of NRCS of USDA
Dec 23, 2015
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