CONTROLLING EROSION ON THE FARM Soils Ag I

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

Land Capability and Land Use

Review of Land Capability Classes  I-IV suitable for cultivation  V-VIII considered not usable for cultivation

Control Measures for Water Caused Erosion

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

Grassed Waterway Shapes

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

Mechanical Erosion Control

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

Terraces

Controlling Wind Erosion

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