Introduction
Wind erosion is an effective agent for causing degradation of the soil. The consequence of this problem is devastating on both man and the climate. It usually occurs in regions with poor vegetation. This paper outlines the types, causes, effects, and prevention methods of wind erosion in order to spur the concern about this problem, hence avert any further damage to the environment.
Body of review
The Dust Watch Australia (2009) website, describes that wind erosion takes place when wind exercises energy that is enough to suspend the soil particles and/or soil aggregates. The suspended soil material travels and settles down in a different location. The length traveled by the entrained particles is dependent on the size of the particles and the power of wind.
The plant and Soil Sciences website (2006), details that wind erosion takes the following forms: “suspension, saltation, and soil creep.” Suspension involves projection and transport of very fine particles of soil in the air to different locations. Saltation is whereby intermediary sized grains moves in a sequence of leaps and bounds. The particles rise and fall successively after short air travels (Yerima & Ranst, 2006, p.380-2). Soil creep is the least means of movement as it involve mass wasting processes that bombards soil grains along the soil surface by saltating particles and under little influence of the strength of the wind. Since they are large and cannot be lifted up by the wind motion, they tend to roll, slide and creep along the surface (Alsharhan, 2003, p. 353).
Wind erosion is caused by several factors. Gaddis and Fenster (n.d) have written that uncovered soil is liable to effects of wind erosion. Bare soils are subject to soil erosion, especially in smooth, loose and dry finely granulated surfaces. Lal (2004, p.109) states that: “anthropogenic activities such as overgrazing, biomass burning, and improper tillage operations”, lead to removal of the protective vegetative coat, hence makes the surface susceptible to agents of wind erosion.
The lighter soil aggregates travels faster than the heavier aggregates. The Ministry of Agriculture Food & Rural Affairs website (2009) demonstrates that the physical characteristics of the soil influence the rate of soil degradation by wind erosion. Soils with higher intensity of organic material and developed soil structure have a greater resistance to effects of erosion. Nutrient deficient sub soils contribute to lower yields of vegetative cover, hence less protection from erosion.
A study by Donk et al. (2002) found out that military training activities affect the vegetative cover, disturb crusts, and disrupt the soil particles, hence makes the ground susceptible to wind erosion.
Drought conditions increase wind erosion as the vegetative cover reduces and the ground becomes pulverized. Felling down of trees causes extensive erosion; the trees anchor the soil with their roots. Absence of trees makes the ground to be susceptible to wind erosion (Butler, 2004).
The effects of wind erosion are devastating. The McGraw-Hill’s Access Science website (2009), reports that wind erosion affects 1,066 million acres worldwide. Wind erosion occurs mostly in flat barren areas where it takes away soil and natural vegetation, which results in dryness and degradation of the soil structure. Ararat (2003) reports that the Australian soil is vulnerable to wind erosion. For example, in February 1983, after the previous year’s drought, a large cloud of dust, which was estimated to carry 250,000 tonnes of dust, passed over Melbourne. In the recent past, other large wind erosion activities have been witnessed throughout Australia.
Motlock (2005) explains that erosion results in a decrease in the quality of the soil, which comes from the loss of the nutrient-rich upper layers of the soil, and the decrease in water-holding capacity of the eroded. This makes the ground to be barren, which results in low crop yields that cannot support the healthy population, hence increases the poverty level, and may even cause death.
Muir (2009) notes that the effects of erosion are felt both in the place where the soil is lost and where it settles upon. This sentiment gets the support of Noel (2001) who emphasizes that erosion has both on-site and off-site effects. For example, eroded soil settles on the leaves of plants, impairs their photosynthetic activity, and hence reduces their normal mechanisms of growth.
The Department of Environment, Climate Change and water website (2009), details that the visual characteristic of wind erosion is dust that consequently has serious health effects. The CSIRO Land and water report by Williams and Young (1999), estimates that the expenses incurred due to health problems from dust to the people of South Australia totals to $50m. The transfer of pathogens, nutrients and contaminants, (Owens et al, cited in Collins & Owens, 2006, p. 4), from one point to another, is facilitated by wind erosion.
Wind erosion causes loss of visibility to the air, this imperils human and animal life as the probability of occurrence of accidents under these conditions are high. Leathers study (cited in Schjonning et al.2004, p.207) indicates that the soil dust is able to cause skin diseases.
The soil material that deposited due to wind erosion often conceals vegetation, overtop fences, and deposit salt (The Department of Environment, Climate Change and Water, 2009).
Erosion destroys the infrastructure (Butler, 2004; Ekhtesasi & Sepehr, 2008). When the surface run-offs transport the eroded soil, they end up into creeks and rivers, and transported downstream, significant siltation problems occur. The riverbeds are raised, which impairs navigation activities, stoppage of hydroelectric projects and irrigation infrastructures occurs, fishing activities are adversely impaired, hence causes tremendous economic losses. The desertification caused by this form of environmental degradation can lead to “environmental refugees”; people who are displaced due to degradation of the environment.
The effects of wind erosion are worrying. To show the concern, effective control methods need to take place to thwart the widespread impacts of this catastrophe. Protective plant cover on the ground effectively reduces wind erosion. Bare fields are at greater risk of wind erosion. The vegetative cover reduces the speed of wind on the ground surface (Dunn, 2001; Morgan & Rickson, 1995, p.133; Bruland n.d.)
Roose (1996) comments that the soil resistance to wind can be done by increasing the cohesion of the soil. Organic matter applied on the ground surface enhances the structure of the soil. Application of oil on the ground surface binds the soil particles hence limits their removal by wind. Supplementary irrigation is practicable in reducing erosion effects.
The Department of Environment and Resource Management (2009) website details that efficient management practices can control wind erosion. This involves the use of equipments that can handle stubble, without burning it, controlling weeds by use of herbicides, and practice of minimum and zero tillage farming methods.
Surface roughening controls erosion by enveloping the ground with soil clods that are big enough to be transported by the wind, and by constructing tillage ridges and furrows that roughens the surface to trap any loose-fitting soil that may be in moving (Leys, 2003).
The California Stormwater BMP Handbook (2003) mentions the following dust control practices for heavily traveled and disturbed areas: “watering, chemical dust suppression, gravel asphalt surfacing, and minimizing surface areas to be disturbed.” The risk of wind erosion is reduced by having small fields that are covered by wind-breakers (AHRF, 2005; Phipps & Milam, 2001).
To reduce the impact of accelerated wind erosion in Australia, Shelterbelts are successfully used (Ararat, 2003). They reduce the wind speed within the premises of the sheltered zone to a level that cannot allow the movement of soil.
The tradition of keeping many animals in a small piece of land should be controlled to avoid the surface becoming bare from overgrazing activities.
Conclusion
The need to save from harm our environment in order to meet the demands of the present and the future generations is awesome. If the continued degradation of the Australian soil due to wind erosion remains unchecked, our children will probably be at loggerheads due to endless conflicts as they try to find means of sustaining themselves.
This nation’s economy is dependent on healthy soil that is able to meet the demands of its citizens. Poor land management practices have detrimental effects both on and off the site of occurrence. The effects of soil erosion can be severe, especially when the rate of the depleted soil occurrence far exceeds the rate of formation of soil. Let us rise up to the occasion to prevent further damage to our beautiful environment.
References
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