11

Soil ErosionSoil Erosion

22

Bird City, Kansas

33

44

St. Francis, Kansas

55

66

77

88

99

San Luis Valley, Colorado

1010

1111

1212

1313

1414

Al Asad, Iraq

1515

1616

1717

1818

1919

The DustbowlThe Dustbowl

2020

How much soil is lost?How much soil is lost?

5 Billion Tons, Billion with a 5 Billion Tons, Billion with a “B” lost each year“B” lost each year

3.5 Billion tons due to Water3.5 Billion tons due to Water

1.5 Billion tons due to Wind1.5 Billion tons due to Wind

2121

What is average loss?What is average loss?

Scientists expect to lose 5 tons per acre per Scientists expect to lose 5 tons per acre per yearyear This much can be re-captured through soil This much can be re-captured through soil

formationformation Water makes up 4.8 tons lostWater makes up 4.8 tons lost Wind makes up 3.3 tons lostWind makes up 3.3 tons lost 8.1 tons is average8.1 tons is average THIS IS TOO MUCH!THIS IS TOO MUCH!

2222

Lasting effects of erosionLasting effects of erosion Loss of topsoil-loss of Loss of topsoil-loss of

productive organismsproductive organisms Organic matter gone along with Organic matter gone along with

N-P-KN-P-K Reduced Root Zone-less water Reduced Root Zone-less water

holding capacityholding capacity Gullies make farming difficultGullies make farming difficult Pollutes lakes, streams causing Pollutes lakes, streams causing

harm to wildlifeharm to wildlife Sediment fills up lakes, streams, Sediment fills up lakes, streams,

and waterwaysand waterways Loss of $$$$ due to un-Loss of $$$$ due to un-

productive soilproductive soil

Sediment fills and pollutes a lake

2323

What affects erosionWhat affects erosion

#1#1 Texture and StructureTexture and Structure

The coarser the texture, the higher infiltration rate, The coarser the texture, the higher infiltration rate, the lower amounts of run-offthe lower amounts of run-off

Fine particles detach easier than large particlesFine particles detach easier than large particles Silt erodes faster than sandSilt erodes faster than sand

Good structures resist rain splash and wind liftGood structures resist rain splash and wind lift

2424

What affects erosionWhat affects erosion

#2 Slope#2 Slope

Length and steepness or grade both need consideredLength and steepness or grade both need considered

Length accounts for volume of erosionLength accounts for volume of erosion

Grade creates water velocityGrade creates water velocity

Long fields have snowball effect with windLong fields have snowball effect with wind Little loss at the head end, piles of soil at the bottom endLittle loss at the head end, piles of soil at the bottom end

2525

What affects erosionWhat affects erosion

#3 Surface Roughness#3 Surface Roughness

Rough soil slows waterRough soil slows water

and reduces downhill flowand reduces downhill flow

Tillage ridges are helpfulTillage ridges are helpful

Tillage across slope prevents erosion, tillage with the slope Tillage across slope prevents erosion, tillage with the slope promotes erosionpromotes erosion

2626

What affects erosionWhat affects erosion #4 Surface Cover#4 Surface Cover

Surface cover reduces Surface cover reduces impact from falling water impact from falling water and slows down movement and slows down movement of waterof water

Surface crops’ roots hold Surface crops’ roots hold soil closelysoil closely

Row crops need a foliage Row crops need a foliage canopy to help protect soilcanopy to help protect soil

2727

What affects erosionWhat affects erosion #5 Climate#5 Climate

Dry soils and dry climates Dry soils and dry climates promote wind erosionpromote wind erosion

The drier the soil particles The drier the soil particles the greater risk of being the greater risk of being picked up and moved picked up and moved elsewhereelsewhere

Dry weather promotes wind Dry weather promotes wind lossloss

2828

Types of erosionTypes of erosion

#1 Splash Erosion#1 Splash Erosion

Water hits the soil and Water hits the soil and can move particles as can move particles as much as 5 feet!much as 5 feet!

2929

Types of erosionTypes of erosion #2 Sheet erosion#2 Sheet erosion

A thin layer of soil is A thin layer of soil is removed as a sheet.removed as a sheet.

Sheet erosion hides until Sheet erosion hides until topsoil is lost and subsoil topsoil is lost and subsoil is exposed.is exposed.

Sheet erosion exposes sub-soil in the circles

3030

Types of erosionTypes of erosion

#3 Rill erosion#3 Rill erosion

Many small channels on Many small channels on slopesslopes

Running water carves Running water carves out rillsout rills

Still can be filled in by Still can be filled in by tillagetillage

3131

Types of erosionTypes of erosion

#4 Ephemeral (e fem er al) #4 Ephemeral (e fem er al)

Large rillsLarge rills

Tillage won’t completely fill Tillage won’t completely fill them inthem in

The next rain will create The next rain will create gullies if not fixed gullies if not fixed

3232

Types of erosionTypes of erosion

#5 Gully erosion#5 Gully erosion

So large equipment So large equipment cannot crosscannot cross

Begin on steep slopes Begin on steep slopes where water creates where water creates enough energy to cut enough energy to cut large channels in the large channels in the earthearth