Water-Caused Soil Erosion

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					Water-Caused Soil Erosion

 This presentation is from Virginia
Tech and has not been edited by the
    Georgia Curriculum Office
 Explain how land capability classes relate to
  wise soil use
 Describe main vegetative methods used to
  control water caused soil erosion
 Describe main mechanical methods used to
  control erosion
 Design proper control strategies
Land Capability Classes
   Range from Class I to Class VIII
   Classes I–IV are suitable for row crop production
     Class I is the best. Nearly flat with little
     Class IV has moderate slopes and is prone to
      high levels of erosion
     Should be covered with vegetation
Class I
Class III
Classes V & VI
 Class V is very nearly level but it may be
  too wet or rocky for crop production
 Class VI is very rocky and steep with very
  shallow topsoil
 Good for permanent grazing and forests
 Overgrazing should be avoided
Class VI
Classes VII & VIII
 Almost impassible
 Limited grazing and forest production
 Class VIII is not suitable for any farming
Class VIII
Class exercise
   classify the land in the following pictures


Control Measures
   Vegetative

   Mechanical
Vegetative Control
 Cover crops
 Crop rotation
 Strip cropping
 Grassed waterways
Cover Crops
 Close growing crop grown on the field
  when the cash crop isn’t growing
 Winter wheat, rye, vetch, etc
 Reduce erosion, improve soils organic
  matter, and improve soil tilth (workability)
Crop Rotation
   Orderly and repeated sequence of different crops
    grown on the same field
   Example: 3–year rotation using corn, soybeans,
   Advantages
      Soil tilth is better

      Improves water absorption

      Reduces erosion

      Increases organic matter

      Improves moisture storing capacity
Strip Cropping
  Alternating bands of different crops
 Laid out on the contour or across a
  prevailing slope
 Hay strip, corn strip, hay strip
 Hay strips increase water absorption, holds
  the soil in place, reduces gullying, & slows
  down running water
Grassed Waterways
   Natural drainageway permanently covered by
   Used widely to prevent gullying in natural draws
   Types
      Trapezoidal

      V–bottomed

      Saucer–most common

   Perrenial grasses such as fescue or bluegrass are
    typically used
   Quickly establish sod (overseed, fertilize, mulch)
Mechanical Control
 Conservation Tillage
 Contour Farming
 Terraces
 Fencing
Conservation Tillage
   Tillage system that is economically practical for
    crop production and aids in soil and water
   Crop residue from previous crop helps protect soil
   Common methods include minimum till, no till
    stubble plant and strip tilling
   Advantages
      Less energy and time are require

      Soil moisture levels increase w/ increase in soil
       organic-matter levels
      Reduces soil erosion
   Disadvantages
     Increase in weed, insect, and disease

     Crop residue ties up nitrogen thus

      requiring more fertilization
Contour Farming
 Plowing around the hill instead of up
  and down it
 Prevents runoff from moving straight
  down the hill
 Larger surface channels constructed on
  a contour with a controlled rate of fall
 Terraces are needed if slope exceeds
  about 2%
 Should be designed by Soil
  Conservation Service
 Example: waterbreaks in old logging
 Fencing cattle away from creeks and
 Greatly reduce creek bank erosion
 Reduces cattle waste from directly
  entering the water source
Developing Control Strategies
A logging crew is moving to this area. The crew plans to clearcut
the forest. What suggestions can you provide the crew to minimize
soil erosion.

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