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19 Cards in this Set
- Front
- Back
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Accelerated erosion
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disturbance due to humans, 10 - 1000 times as destructive as geological erision
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3 steps of vater erosion
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Detatchmment - from soil mass
Transportation - downhill Deposition - at lower elevation |
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Sheet erosion
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splash soil removed uniformly, leaving tiny soil colummns
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Rill erosion
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once sheet flow is concentrated into tiny channels. common on bare land. small channels can be smoothed
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Gully erosion
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Rills deepen and coalesce into larger channels called gullies. obstacles for tractors, cannot be removed by tillage.least noticible
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USLE
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A = R*K*LS*C*P
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R
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rainfall erosivity. rainfall amount and intensity.
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K
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erodibility. considers infiltration capacity and structural stability. high K for silt and very fine sand, expansive clay. low K in high OM soil, nonexpansive clays, strong granular structure
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LS
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Topographic factor. influence of length and steepness of slope
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C
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cover and management factor. low ffor undisturbed forests and dense grass. next forage crops, then intermediate for small grains, high val for row crops like corn and soybeans
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P
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support factor. physical structures that guide or slow runoff flow.
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Contour cultivation
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rows follow contours across slope gradient.
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Terraces
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reduce effective length and gradient of slope. collected water flows gently across field.
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Erosion control - cover
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vegetation, mulch, and pavement
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Erosion control - controlling flow
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Terraces, diversions, waterways.
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Erosion control - trapping sediment
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sedimentation and retention ponds.filtering sediment barriers. ponds deposit sediment and clear water is skimmed off
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Wind induced transportation
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Saltation - short bounces close to ground
Soil creep - rolling and sliding along surface of larger particles Suspension - fine particles move parralel to surface and upward. |
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conditions promoting wind erosion
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high windspeed, smooth soil surface, dry soil, sandy soil, no vegetation.
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Conservation Reserve Program (CRP) land
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govt paid farmland planted with grasses or trees by farmers.
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