Emergency Wind Erosion Control on Flood Affected Land

Generally, wind erosion has been a concern in western Kansas.  Wind velocities in central and eastern Kansas are much lower than in western Kansas so the occurrence of wind erosion is less likely.  However, some of the bottomland in central and eastern Kansas has also been susceptible to erosion by wind. Flooding in 1993 deposited large quantities of silt and sand on bottomland along streams in central and eastern Kansas.  Some of these deposits are very erodible.  Working this silt or sand into the topsoil can increase a soils susceptibility to wind erosion.  Even pastureland that is over-grazed or received deposition could be susceptible if no good cover is established.

Wind erosion causes damage by removal of topsoil, deposition in undesired locations (such as road ditches), endangers traffic by limiting visibility, and causes air pollution.  Wind erosion is influenced by several factors; wind speed and direction, surface moisture, size and strength of clods, field length and soil cover.  The best control of wind erosion is achieved with a protective cover of residue and/ or growing crop.  However, flood affected bottomlands could lack a cover due to heavy sand and silt deposits.

Establishing a cover crop or cover strips on this land is the preferred method for wind erosion control.  If weeds are present, use of a herbicide for their control rather than tillage should be considered.  The dead weeds on the undisturbed soil could provide some protection. Freeze-thaw cycles during the winter will break down soil clods, thus reducing a soils ability to withstand wind erosion.  If no cover can be established, wind erosion could be a very serious threat in the winter or spring.

Preventive measures

Wind erosion can also be prevented by the use of wind breaks, snow fences or application of manure, treated sewage sludge or crop residue to the soil.  At least 1.5 to 2 tons of wheat straw or 3 to 4 tons of corn or sorghum residue per acre is needed to be effective.  Crop residue should be anchored at right angles to the prevailing wind direction with a disk set straight.

Once wind erosion has started it is difficult to stop further damage.  Loss of soil in blow spots and deposition of soil will occur.  Immediate action is required to prevent total loss of a field and possible adjacent fields.  Placing manure, or anchoring crop residue on the small blowing spots can prevent the avalanche effects of wind erosion.  Snow fences could be used for larger areas.  Applying water with a sprinkler irrigation system will control wind erosion temporarily.  As a last resort, emergency tillage might be used.

Emergency tillage

Emergency tillage is a short-term solution to wind erosion control; its effects are only temporary.  The purpose of emergency tillage is to create a rough cloddy surface that resists the force of the wind.  Clods of 3/8-inch diameter or larger are needed.  Narrow chisels (2 inches wide) are most often used; they require less power and will do none or little damage to a growing crop such as winter wheat.  The effectiveness of emergency tillage depends on soil moisture content, speed and depth of tillage, and chisels spacing.  Tillage must be performed perpendicular to the wind direction. The best effect is achieved at tillage speeds of 3.5 to 4 miles per hour.  Research shows that lower speeds of 2 to 3 miles per hour result in more and larger clods, while higher speeds of 5 to 7 mph, create the greatest field roughness. Lower speeds are recommended when tilling in anticipation of erosion, while higher speeds should be used where erosion has occurred. Under normal soil conditions, a depth of 3 to 6 inches will bring enough clods to the surface to control erosion.  Usually chisel spacing of 27 to 54 inches and tilling about 50 percent of a field will be sufficient.  Under severe wind erosion conditions, some fields might have to be tilled completely or even twice, splitting the chisel spacing, to control erosion.

On fields with large quantities of sand or silt in the top layers, chisels might not produce enough clods to stop wind erosion.  A moldboard lister (40 to 60 inch spacing) could be used to create enough surface roughness. Tillage should be shallow (4 to 5 inches deep).

If erosion persists, deeper tillage can be performed.  Emergency tillage on fine sandy soils is ineffective after a number of operations.

Wind erosion is a function of field length. Often several adjacent fields will have to be treated with emergency tillage to sufficiently control the erosion.  Erosion protection by treating just one field while erosion occurs on the surrounding land is very short lived.

Summary

Sand and silt deposits might increase the susceptibility of soils to wind erosion.  Wind erosion could occur in central and eastern Kansas.  The best method to control wind erosion is to cover the soil by either crop residue or a growing crop.  If wind erosion occurs, be prepared to perform emergency tillage with a narrow chisel or moldboard lister.  Before tilling agricultural land, contact the SCS to verify requirements for highly erodable land (HEL).

            November 1993