1. Ag I Soils

2.  Differentiate between natural soil erosion and soil erosion caused by humans  List the main causes of accelerated erosion  List and define the major types of soil erosion

3.  Natural process that occurs all the time  Part of the soil formation process  Much slower than soil formation

4.  A speed up of the normal rate of erosion  Begins when land’s natural plant cover is removed  Caused by two basic forces-moving water and wind

6.  Occurs when raindrops strike the earth Raindrops hit at about 20 MPH  If raindrops strike plants their force is broken and they become harmless  If raindrops strike bare soil the force is absorbed by soil particles and they are torn apart  When this happens the soil particles are either suspended and carried away or filter into soil pore spaces making the soil less permeable.

7.  Most destructive action of water on soil  The faster the water flows the more destructive it becomes  Three-fold damage Existing soil structure is damaged Soil surface is reshaped making it less workable Soil is carried away and may eventually be redeposited elsewhere  Silt deposits can sometimes be good  Nile Valley, Mississippi Delta  Most are harmful causing clogged waterways, fish kills, filled lakes, muddy streams and mud flats

10.  2 basic actions-drying and dislodging, movement  A serious problem in dry areas where the land is relatively flat with few trees

11.  Dries the soil surface  Moves soil particles leaving behind larger sand particles making soil surfaces become very sandy or covered by a layer of clay

13.  Gradual and fairly uniform removal of the surface soil  Occurs slowly so producer may not even be aware it is taking place  Caused by splash erosion coupled with a slow runoff of soil-laden water

14.  Gradual reduction of the topsoil thickness This leads to a decrease in soil productivity and eventually totally unproductive soil  Also notice color changes in the soil in plowed fields because as they are plowed subsoil is brought to the top Discoloration is a indication that sheet erosion is well advanced and damage has already been done

16.  More rapid and visible  Rills are small streams cut into the soil surface by running water  Damage has occurred when rills appear May be very small or large and noticeable  When rills become too large they become a gully

18.  Obvious  Severe problem  More obvious than rill or sheet erosion

20.  2 forms of damage Soil removal Sand deposits or drifts

21.  Much like sheet erosion  Wind simply picks up the soil particles and blows them away  As soil blows away The field becomes less productive It retains less rainwater It produces less vegetation  Damage may be severe before it becomes obvious

23.  More obvious  Result when the wind is forced to change directions abruptly Fencerows, windbreaks, sides of buildings When the wind changes direction it redeposit's the soil particles  Larger and more flat bare fields are the more likely they will be affected by wind erosion

25.  Watch Modern Marvels: Black Blizzard and complete questions