Soil Erosion: Causes, Control & Estimation AGME 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 RaindropSheetInterrill Erosion Rill ErosionGully 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) (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