Soil erosion

Erodes clay and organic matter with nutrients Reduces pedon thickness, volume of soil providing water and nutrients to roots Impeded machinery and animal movement Increases pollution

Texture - silt sized particles Structure - aggregation resists detachment and transport, stabilized by organic matter, Fe and Al oxides, clays Slope

Rain drop detachment Transport Then Deposition

Favored by ponding, result of raindrops sealing soil surface, rainfall exceeding infiltration

Sheet - runoff in thin sheets Rill - runoff in many small channels (rills), deeper Gully - runoff in a single wide, deep channel

A = RKLSCP A - long term average annual soil loss for a location R - long term average rainfall runoff erosivity factor K - erodibility index (texture and structure) L - slope length factor S - slope angle factor C - soil cover factor P - erosion control practice factor

Cover - anchors soil and slows water Mechanical - reduce slope length and steepness Tillage - cover to reduce runoff, grass waterways, strip cropping, conservation tillage Problems with weed, disease, insect control Planting into residues

E - potential average annual quantity of erosion I - soil erodibility (particle size dependent) C - local climate factor K - soil roughness L - width of field (unprotected by wind barriers) V - quantity of vegetative cover

NOT SOLID WALL (wind turbulence of downwind side) Trees and shrubs (sheltered distance increases with horizontal length of windbreak)

Cover - holds soil, increases roughness, preserves moisture, holds snow, keeps moist in spring Cultivation - increases surface roughness, cultivate perpendicular to prevailing wind

Landslide - rapid Soil creep - slow, persistent

Assisted by water which 1) decreases friction 2) Increased weight Favored by steep slopes and clay soils or clay layers in soils Prevented by vegetation with deep roots which use water, increasing friction, and promote root binding

Reduce machinery weight, reduce number of trips, keep off wet soil Compaction can be reduced by special deep tillage methods Crusting can reduced by light cultivation, adding gypsum, mulches