Causes and Effects of Soil Erosion - Term Paper Example

SOIL EROSION By (Name) Institution Instructor Class/Course City Introduction The term soil erosion means the destruction of soil by the action of wind and water. Some authors have modified this definition to include damage that is caused as a result of human actions (Zacharp, 2011, p.22). Soil erosion causes much damage. Apart from environmental damage involved, the financial losses associated with soil erosion are immense. For instance, America loses between $30 billion and $44 billion to soil erosion annually (Pimental et al, 1993), whereas the United Kingdom also loses about £90 million (Environment Agency, 1989).The purpose of this study is to examine the causes of soil erosion, its effects on the environment and the solutions available to control it, for the purpose of academic study. The Causes of Soil Erosion Soil erosion is mostly caused by climatic factors. They include rainfall and wind as the major factors. Other factors that contribute to soil erosion are mostly caused by human activities. Such activities include mining, urbanization and vegetative clearing. The topography of the land also contributes to soil erosion. Rainfall intensity contributes greatly to soil erosion. It is, usually, the main agent of erosion. The amount of intensity influences the magnitude of the erosion. It is the most critical factor. As argued by Blanco (2008 p.29), the greater the intensity of the rainstorm, the greater the runoff and consequently, soil erosion. Vegetative clearing is another factor that contributes to soil erosion. It is estimated that about 1 million hectares were cleared from the year 2000 to 2010 (SOE 2011 Report). Vegetation has a great role in preventing soil erosion. It reduces the destructive energy of rain by increasing the soil roughness. This is effective in slowing the runoff velocity. The vegetation also filters the soil particles in the runoff thus preventing further erosion. With less vegetation, the detachment of soil particles increases thus making the soil prone to erosion. Although vegetation is crucial in providing cover and averting erosion, not all vegetation plays this role effectively. Dense and short growing form of vegetation, for instance, grass, is preferable to sparse and tall vegetation. Dense canopies also limit splash erosion, therefore, reducing soil erosion (Blanco, 2008). Population pressure greatly contributes to soil erosion. In China, for example, an exponential rise in erosion with a rise in the total population was recorded since 220 BC (Wen, 1993). When the population is large, land becomes scarce, forcing people to farm on marginal land. The farming practices carried out on these lands are, usually, unwise and therefore lead to soil erosion (R. P. C. Morgan). For example, people often farm in mountainous regions such as The Himalayas in China thus exposing the soils to soil erosion. Rural to urban migration also contributes to soil erosion. People move to urban areas in search of jobs thus leaving arable land untended. This leads to soil erosion as well. The methods used in management of land also contribute to soil erosion. In Australia, for example, 46% of the land is used for grazing, and a further 9% is used as modified pasture. An obvious consequence of grazing is the fact that it leads to the loss of vegetative cover which in turn leads to soil erosion. Mining is another way of utilizing land. About 3 million hectares of land in Australia is used for mining (SOE 2011Report). The Western Australia Goldfields (Gold and Nickel), The Pilbara (Iron ore), Hunter Valley (Coal), and Bowen Basin (Coal and gas) are examples of where mining takes place. These are huge tracts of land compared to other countries. Excavating land in the process of mining leaves soil particles loose and exposed to destructive elements of the weather such as wind and rain thus making the land prone to soil erosion. Other agricultural practices such as overhead irrigation also contribute in enhancing soil erosion. Excessive cultivation is also another practice that has contributed to soil erosion. Excessive cultivation often leads to the rough particles in soils to break down to form smaller particles. These small particles are, usually, less erodible due to the ease they can be displaced from the soil. Some agricultural practices also lead to the destruction of vegetative cover, for instance, the clearance of vegetation to provide arable land. Effects of Soil Erosion There are many adverse effects of soil erosion. They have an adverse effect on the fertility of the soil. Soil erosion leads to the loss of the top layer of soil. This erosion of the top soil has dire consequences to agriculture. For instance, the loss of top-soil leads to a reduced ability to store water and nutrients. It also leads to an increased rate of runoff, therefore, washing away nutrients and the loss of newly planted crops. It also leads to the exposure of sub-soils which, usually, have poor physical and chemical characteristics. Such situation leads to the loss of arable land. This may result in food insecurity in the future. Soil erosion leads to the reduction of quality of aquatic life. The sediments deposited in water, usually, discolor the water. This makes it difficult for light to penetrate the water. This lack of light poses a problem for aquatic plants since they need sunlight in order to carry out photosynthesis. Another challenge is eutrophication. The sediments are, usually, fertile and contain nutrients such as Nitrogen and Phosphorus, which result in the growth of algae. These algae use up Oxygen, therefore, depriving other organisms of oxygen and therefore leading to the death of aquatic organisms. The quality of air also reduces. Soil particles are sometimes carried by wind. In these circumstances, they may cause respiratory problems to both animals and human beings. In the case of concentrated particles, they may lead to decreased visibility. The State Of Soil Erosion The total land area is managed by 136 000 businesses which account to 52% of the total land area. State forests, national parks and public land accounts for 25% managed by the Australian and state governments. Indigenous people control and manage 23% of the land in which they are legally entitled to. The rest small portion of the land is managed by mining companies and residents who live in suburbs near urban centers (SOE 2011 Report). The Millennium drought that affected Southern Australia from 2001 to 2010 adversely affected industries. This caused reappraisal risks in irrigation regions prompting a shift to high-value crops on small areas which resulted in the efficient using of water in irrigation. In Murray Darling Basin, the production per unit of water used increased. Sophistication of agricultural methods has reduced the intensity of agricultural chemical use. This has led to the flexible approaches to grazing management that has reduced erosion while increasing productivity. The area covered by public native forest has declined by approximately 20%. Plantation forests have increased in contrast, after a huge investment. However, they are expected to shrink with the expansion expected to shrink by 50% in the next decade. Coal mining has expanded, especially in prime agricultural land has led to a competition for land, water and other resources. This has raised concerns about water contamination. The expansion of infrastructure to handle the exports has put a strain on the natural resources. Urban areas and coastal settlements in Australia have continued to grow. However, the government has tried to manage and control these settlements in a bid to protect the biodiversity of the agricultural lands and areas prone to flooding. In Peninsular, Burkedin and Fitzroy province, land management in the grazing and cropping lands is improving. However, localized erosion has continued at an unsustainable rate. In New England-Moretown and Macquarie Upland provinces, management of surface cover has improved in most areas although erosion is still significant in the less fertile land. In the Tasmanian Uplands province, intensive agriculture has led to the rates of soil erosion being unsustainable. There is also widespread hillside erosion in the West and South West due to wildfires that have destroyed the vegetation. In Kosciuszkan Uplands Province, the diverse lands experience severe gully and sheet erosion as a consequence of wildfires. In the Carpenteria Lowlands province, the main cause of erosion is clearing and grazing. In Central Lowlands Province, wind erosion is widespread in the central and western areas. Hills Slope erosion is caused by the grazing of stock and feral animals. However, the rate of erosion has increased. In Murray Lowland Province, there is extensive wind erosion that is attributed to the dune fields. The increased surface cover however has helped reduce it. In North Australian Plateau province, sheet and gully erosion is in areas that have been cleared for livestock. These areas are also vulnerable to rainfall intensity. Although sheet erosion and gully in Kimberley have been reduced, the areas with less vegetative cover still have unsustainable rates of erosion. In Central Australian Ranges Province, there is extensive wind, gully and sheet erosion as subject to the grazing. In Carpentaria Province, erosion rates have slowed down especially in the South Eastern part. In Sadland, Pilbara and Western Coastland provinces, gully erosion is in areas subjected to grazing by both feral and stock animals. The Province of Yilgram Plateau, there is wind erosion especially in the North while, in Nullabor Province, erosion rates are relatively stable apart from the parts where grazing takes place. Finally, Eyre Peninsula and Gulf Ranges provinces have a long history of unsustainable rates of wind and water erosion. However, land practices and management practices have reduced the rate of erosion. Solutions to Soil Erosion As argued by Humberto (2008), soil functions are becoming more complex and diverse and therefore there is a need to improve soil conservation and management practices. Effectively managing the emerging issues, requires the invention of new technologies, formulation of new policies and the improvement of current practices of soil and water conservation methods. Lessons from the past should form the guiding principles. Better land practices have been implemented while others are in the process. For instance, mulch is being applied. Cover crops are also being planted. This helps in preventing the loss of soil particles through the eroding agents such as wind and rainfall. Farmers have also been encouraged to adopt better farming practices. The government, for instance, has given the indigenous Australian people a responsibility to take care of forests and land thus preserving the land. Good grazing patterns have also been encouraged and especially at critical times so as to conserve the vegetative cover. Land management practices are being monitored. This is being done during a long period to identify the trends in soil erosion patterns. Technology, in the form of remote sensing, has made it possible to monitor the bare soil and its surface cover. This helps in giving a reliable estimate for the purpose of management. The collected data has been made available to The Australian Bureau of Statistics for the purpose of evaluation. Other practices such as which put pressure on the land are being discouraged and regulated. For instance, mining has been regulated to avoid its adverse effects. Engineering of infrastructure that degrade the soil have been encouraged to adopt solutions which are harmonious to the environment to preserve the soil. References Blanco, H. & Lal, R. 2008. Principles of Soil Conservation and Management. Springer Environment Agency, 2002. Agriculture and natural resources: benefits, costs and potential solutions. Environment Agency, Bristol. Food and Agriculture Organization Of The United Nations. 2008. Soil erosion by water: some measures for its control on cultivated lands. Rome, Food and Agriculture Organization of the United Nations. Hatton, D. 2011. State of Environment State and Trends of Land Management. Hudson, N. W. 2003. Field measurement of soil erosion and runoff. Morgan, R. P. 2005. Soil Erosion and Conservation. Blackwell Science Ltd Pimental, et al. 2005. Environmental and economic costs of soil erosion and conservation benefits. Summer, W. 2008. Modelling soil erosion, sediment transport and closely related hydrological processes: proceedings of an international symposium held at Vienna from 13 to 17 July 1998. Wallingford, IAHS Press. Zachar, D. 2011. Soil Erosion, Developments in Soil Science vol. 10. Elsevier Read More