Control Wind Erosion

 The basic principles in the control of wind erosion are breaking of wind velocity at the soil-atmosphere interface and the reduction in soil erodibility. A suitable surface soil texture is the best key to wind erosion protection. Properly managed crop residues carefully timed soil tillage, and accurately placed crop strips and crop barriers can all effectively reduce wind erosion. Proper land use and adaptation of adequate moisture conservation practices are the main tools that help in wind erosion control. Three basic methods can be used to control wind erosion:

1. Maintain Vegetative Cover (Vegetative Measures)

2. Roughen the Soil Surface by Tillage Practices (Tillage Practices or may be called Tillage Measures)

3. Mechanical or Structural Measures (Mechanical Measures)

1. Vegetative Measures

 Vegetative measures can be used to roughen the whole surface and prevent any soil movement. The aim is to keep the soil rough and ridged to either prevent any movement initially or to quickly trap bouncing soil particles in the depressions of the rough surface.

 From the basic concept, the velocity of wind decreases near the ground surface because of the resistance offered by the vegetation. The variation in wind velocity with respect to a height above the land surface increases exponentially.

2. Tillage Practices

 The tillage practices, such as ploughing are importantly adopted for controlling wind erosion. These practices should be carried out before the start of wind erosion. Ploughing before the rainfall helps in moisture conservation. Ploughing, especially with a disc plough is also helpful in the development of rough soil surface which in turn reduces the impact of erosive wind velocity. Both the above effects are helpful in controlling wind erosion.

 Surface roughening should only be considered when there is insufficient (less than 50%) vegetation cover to protect the soil surface or when the soil type will produce sufficient clods to protect the surface

3. Mechanical Measures

 This method consists of some mechanical obstacles, constructed across the prevailing wind, to reduce the impact of blowing wind on the soil surface. Generally, in practice two types of mechanical measures are adopted to control wind erosion; i) windbreaks and ii) shelterbelts.

i) Wind Breaks

 The term windbreak is defined as any type of barrier either mechanical or vegetative used for protecting the areas like building apartments, orchards or farmsteads, etc. from blowing winds. The windbreak acts as a fencing wall around the affected areas, normally constructed by one row or maximum up to two rows across the prevailing wind direction.

 A further use for "windbreaks" or "wind fences" is for reducing wind speeds over erodible areas such as open fields, industrial stockpiles, and dusty industrial operations. As erosion is proportional to the cube of wind speed, a reduction in wind speed by 1/2 (for example) will reduce erosion by over 80%. The largest one of these windbreaks is located in Oman (28 m high by 3.5 km long) and was created by Mike Robinson from Weather Solve Structures.

ii) Shelter Belts

 Shelterbelts are strictly living windbreaks. It is a longer barrier than the windbreak, is installed by using more than two rows, usually at a right angle to the direction of prevailing winds. The rows of belts can be developed by using shrubs and trees. It is mainly used for the conservation of soil moisture and for the protection of field crops, against severe wind erosion.

 A shelterbelt is more effective for reducing the impact of wind movement than a windbreak. Apart from controlling wind erosion, it provides fuel, reduces evaporation, and protects the orchard from hot and cold winds.