WIND ERROSION

Wind ErrosionHASEEB ZAHID

Mahies2008-ag-1708Semester: 7th

Dept:AGRONOMY

WIND ERROSION

Detachment, transportation, and deposition of loose topsoil or sand

by the action of windIn one, the sediments are carried by the wind and are

usually fairly small. In the other, the sediments are carried by

moving water and the sediment size can be quite divers

Wind erosion is very selective, carrying the finest particles -

particularly organic matter, clay and loam - many kilometers.

Factor effecting wind erosion• Aridity of climate. Wind erosion can also take place in high-rainfall climates

when certain months of the year are particularly dry .It tends to be slight in barani areas however, except where rainfall is less than 600 mm.

• Soil texture. Loamy sand, rich in particles between 10 and 100 microns in size, is the most vulnerable soil (More clayey soil is much stickier, better-structure}.

• Soil structure. The less structure-improving matter a soil has on the surface (organic matter, iron and free aluminum, lime), the more fragile

• State of the soil surface. If the soil surface is stony, forming a the risks of wind erosion are lower -

• Vegetation. Stubble and crop residues in the soil cut wind-speed at ground level.

• Soil moisture increases cohesion of sand and loam, temporarily preventing their erosion by wind.

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•Soil Surface RoughnessSoil surfaces that are not rough or ridged offer

little resistance to the wind.

• Light mineral soils (sandy soils) or soils containing dry aggregates that are under 0.5 mm in diameter are also vulnerable to wind erosion, as are soils with a humid surface layer

• Lack of ridges

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CAUSES OF WIND ERROSION

• Erosion occurs with strong, turbulent winds blowing across a soil surface that is smooth, loose, dry and finely granulated

• Removal of crop residue for feed, by tillage operations, or by burning can lead to serious wind erosion in problem areas. Marginal cropland areas that produce little residue in low rainfall regions contribute to conditions ideal for wind erosion.

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• DROUGHT• POOR FARMING PRACTICES (over tillage)• POOR PLANNING• BURNING• OVER USE OF HERBICIDES• Loss of vegetation

CAUSES OF WIND ERROSION

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TYPES OF WIND ERROSIONSaltation:bouncing of particle : (0.004-0.02 inch)

Surface Creeping: (0.02-0.04 inch)particlesSuspension: (0.004 inch)particles

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IMPACTS OF WIND ERROSION

• Loss of crop production.• Loss of property value.• Loss of nutrients.• loss of aesthetic value of agricultural lands.

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WIND EROSION SUSCEPTIBILITY

• The drier the soil and the higher the concentration of fine sand, the greater its susceptibility to wind erosion. Heavy clay soils may also be affected during very dry conditions if the structure has been damaged by stock, traffic or excessive cultivation.

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Prevention of wind errosion• Emergency tillage - Emergency tillage provides a

roughened, cloddy surface resistant to wind erosion. Surface roughness reduces the wind velocity .

• Ridges should be formed at right angles to prevailing winds.

• Chisels are the most common tool used to roughen the soil and bring clods to the surface. In growing wheat, 2-inch chisels spaced 3 feet apart and operated 4 to 6 inches deep will usually bring sufficient clods to the surface to reduce wind erosion.

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Prevention of wind errosion• Covering soil with manure or straw

Manure is preferred as a soil cover because it also enhances soil fertility and tilth.

• Avoid overgrazing

• Minimum Tillage

• If you do till, choose a tillage implement that buries less residue

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Shelterbelts

Creating shelterbelts along the border of field can provide extra protection against wind erosion no matter what cropping system is used.

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Increasing surface roughness

A rougher surface reduces wind speed at the soil surface so the wind is less able to move soil particles.

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Controlling vegetative cover

Vegetative cover is one of the keys toeffective erosion control. Vegetation include growing of

grass and leguminous crop.

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Contour and Strip Cropping

Contour strip cropping will reduce soil losses even further. Strip cropping, ideally, involves alternating strips of forage and a row crop on the contour.

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Mulching

• Mulching consists of the application of plant residues or other suitable materials to the soil surface. Mulching reduces erosion potential by protecting the exposed soil surface from direct impact by wind

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CROP ROTATION

. CROP ROTAION INCLUDES LEGUMES AND GRASS WHICH OFTEN INCREASE SOIL AGGREGATION MINIMIZE ERROSION.

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