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Soil Erosion PS U6 L9.

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Presentation on theme: "Soil Erosion PS U6 L9."— Presentation transcript:

1 Soil Erosion PS U6 L9

2 Bird City, Kansas


4 St. Francis, Kansas





9 San Luis Valley, Colorado





14 Al Asad, Iraq





19 The Dustbowl

20 How much soil is lost? 5 Billion Tons, Billion with a “B” lost each year 3.5 Billion tons due to Water 1.5 Billion tons due to Wind

21 What is average loss? Scientists expect to lose 5 tons per acre per year This much can be re-captured through soil formation Water makes up 4.8 tons lost Wind makes up 3.3 tons lost 8.1 tons is average THIS IS TOO MUCH!

22 Lasting effects of erosion
Loss of topsoil-loss of productive organisms Organic matter gone along with N-P-K Reduced Root Zone-less water holding capacity Gullies make farming difficult Pollutes lakes, streams causing harm to wildlife Sediment fills up lakes, streams, and waterways Loss of $$$$ due to un-productive soil Sediment fills and pollutes a lake

23 What affects erosion #1 Texture and Structure
The coarser the texture, the higher infiltration rate, the lower amounts of run-off Fine particles detach easier than large particles Silt erodes faster than sand Good structures resist rain splash and wind lift

24 What affects erosion #2 Slope
Length and steepness or grade both need considered Length accounts for volume of erosion Grade creates water velocity Long fields have snowball effect with wind Little loss at the head end, piles of soil at the bottom end

25 What affects erosion #3 Surface Roughness Rough soil slows water
and reduces downhill flow Tillage ridges are helpful Tillage across slope prevents erosion, tillage with the slope promotes erosion

26 What affects erosion #4 Surface Cover
Surface cover reduces impact from falling water and slows down movement of water Surface crops’ roots hold soil closely Row crops need a foliage canopy to help protect soil

27 What affects erosion #5 Climate
Dry soils and dry climates promote wind erosion The drier the soil particles the greater risk of being picked up and moved elsewhere Dry weather promotes wind loss

28 Types of erosion #1 Splash Erosion
Water hits the soil and can move particles as much as 5 feet!

29 Types of erosion #2 Sheet erosion
A thin layer of soil is removed as a sheet. Sheet erosion hides until topsoil is lost and subsoil is exposed. Sheet erosion exposes sub-soil in the circles

30 Types of erosion #3 Rill erosion Many small channels on slopes
Running water carves out rills Still can be filled in by tillage

31 Types of erosion #4 Ephemeral (e fem er al) Large rills
Tillage won’t completely fill them in The next rain will create gullies if not fixed

32 Types of erosion #5 Gully erosion So large equipment cannot cross
Begin on steep slopes where water creates enough energy to cut large channels in the earth

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