controlling erosion on the farm soils ag i. objectives* explain how land capability classes relate...
TRANSCRIPT
Objectives*
Explain how land capability classes relate to wise soil use
Describe the main vegetation methods farmers use to control water-caused erosion
Describe the main mechanical methods farmers use to control water-caused erosion
Describe the control measures farmers use to control wind-caused erosion
Explain why soil erosion control should be important to every farmer
Review of Land Capability Classes
I-IV suitable for cultivation V-VIII considered not usable for
cultivation
Vegetative Control
Cover crops Close growing Improve organic matter content, structure
and tilth of the soil Green-manure crops
Cover crops that have been tilled under Close growing grasses and clovers work
best for both cover and green-manure crops
Crop Rotation
Orderly and repeated sequence of different crops grown on the same field 3 year rotation- Corn, soybeans, wheat 4 year rotation corn, cotton, oats, hay or
pasture Sequence is repeated every 3-4 years Many possible rotations to use with
success
Advantages of Crop Rotation
Soil tilth is better maintained Soil water absorption is improved Erosion danger is lessened Organic matter content is increased If a legume is included, nitrogen fixation
helps supply that costly plant nutrient Soil tillability is improved Moisture storing capacity of the soil is
improved
Strip Cropping
The production of alternating bands of different crops
Used to control both wind and water erosion Sloping lands
Strips are laid out either on the contour or across the prevailing slope
Typical strip cropping scheme alternates row crop, hay, row crop Example- 3 year rotation of corn-soybeans-hay the
strips of hay would make up 1/3 of the field while the corn or soybeans would make up the other 2/3. Strips would be alternated annually
Permanent Strip Cropping
Variation is permanent strips of cover crop, pasture, or hay alternated with a row crop with or without a crop rotation system
Effect is to provide bands of heavier vegetation alternated with row-cropped bands. Heavier vegetation
Increases the rate of water absorption Holds the soil in place better Cuts down on gullying Improves soil tilth in the band Also serves the slow down run-off to lessen its cutting
power
Grassed Waterways
Widely used throughout the world Best used in a fields natural draws and
drainageways In terraced or contour fields used as a
release for the water from the row or terrace
Construction of Grassed Waterways
3 shapes Trapezoidal Triangular Saucer
Most common is saucer shaped
Best Grasses for Grassed Waterways
Fescue Bermuda Bluegrass When planting the grasses the seedbed
should be seeded at 2 to 3 times the normal rate
Conservation Tillage
Any tillage system that is economically practical for crop production and aids in soil and water conservation
Techniques differ across the country Common techniques
Minimum tillage No till Zero till Stubble plant Chisel plowing Lot planting Strip tilling
Advantages
Less energy and time are required as the amount of tillage is decreased
Soil moisture levels increase with the increased soil organic-matter level
Soil erosion is better controlled
Disadvantages
Increase in weed, insects and disease problems
Heavier fertilization may be required due to crop residues tying up soil nitrogen
Increased herbicide use is needed to kill weeds
Exsisting equipment may not be well suited to conservation tillage
Contour Farming
Plowing “around” the field Rows act like small damns to slow run-off Rows should not be laid out straight
across the slope, they should run downhill slightly to allow runoff to be conducted in the desired direction
Also works to control wind erosion if rows are plowed across the prevailing winds, then each row of crop acts as a mini shelterbelt
Terraces
Larger surface channels constructed on the contour with a controlled rate of fall
Designed to accept runoff and conduct it across the slope to some protected area
Needed on slopes that exceed 2% and where the slope is over a few hundred feet long
Windbreaks
Trees or shrubs planted across the prevailing winds
Reduce the cost of heating and cooling the home
Help keep soil moisture from evaporating as rapidly
Shelterbelts
Planted to provide protection to crops and livestock
Consists of trees and shrubs Height and density determine
effectiveness Reduce the effects of high wind up to 20
times the windbreak height
Conservation Tillage
Conserves soil moisture Reduces surface wind speed Holds loose soil particles in place One exception-
In areas of low wind erosion danger farmers will sometimes cultivate the surface of the soil into a loose, sandy layer to conserve soil moisture
Summary*
Best erosion control is to use the land according to it capability
Vegetative controls for water erosion include-cover crops, crop rotation, strip cropping, grassed waterways
Mechanical controls for water erosion include conservation tillage, contour farming and terraces
Wind-caused erosion controls include windbreaks, shelterbelts, conservation tillage and contour farming