Meaning of Soil Erosion: All land use activities, particularly those which are poorly managed, involve destruction soil erosion essay disturbance, to a greater or lesser extent, of natural and semi-natural ecosystems. o Rill erosion: Rill erosion is the most common form of erosion. The soil is also broken up by weathering processes, both mechanical, soil erosion essay, by alternate wetting and drying, freezing and thawing and frost action and biochemical. If the soil erosion essay of animals is within the carrying capacity, the grass is able to grow again, but if there are too many animals it may not have sufficient time to recover and may be killed. Soil deterioration and low quality of water due to erosion and run off has often become a severe problem around the world. Impact of Soil Erosion: The rapid erosion of soil by wind and water has been a problem ever since land was first cultivated. Soil erosion is a natural process that is often healthy for the ecosystem, but it has been increased by human activities that make it occur much faster than under natural conditions, contributing to soil degradation.
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Soil erosion is a gradual process that occurs when the actions of water, wind, and other factors eat away and wear down the land, causing the soil to deteriorate or disappear completely. Soil deterioration and low quality of water due to erosion and run off has often become a severe problem around the world. Many times the problems become so severe that the land can no longer be cultivated and is abandoned. The key to minimizing soil erosion and saving the farm lands is the farmer himself, soil erosion essay. Ultimately, he is the one who must reduce the level at which erosion sediments are dislodged from his cropland.
This program will discuss the erosion process, its effects on crops and the environment, and the Best Management Practices that can be implemented to limit or contain soil movement from the land. Soil erosion can be divided into two very general categories: · Geological erosion: Geological erosion occurs where soil is in its natural environment surrounded by its natural vegetation. This has been taking place naturally for millions of years and has helped create balance in uncultivated soil that enables plant growth. A classical example of the results of geological erosion is the Grand Canyon. Accelerated erosion is the type that will be covered in most depth.
It includes such problems as The action of wind on exposed sediments and friable rock formations causes erosion abrasion and entrainment of sediment and soil. Eolian action also forms and shapes sand dunes, yardangs streamlined bedrock hills and other landforms. Subsurface deposits and roots are commonly exposed by wind erosion. Wind can also reduce vegetation cover in wadis and depressions, scattering soil erosion essay remains of vegetation in interfluves. Stone pavements may result from the deflation r Continue reading this essay Continue reading. Toggle navigation MegaEssays, soil erosion essay. Saved Essays. Topics in Paper, soil erosion essay.
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Accelerated erosion is the type that will be covered in most depth. Eolian action also forms and shapes sand dunes, yardangs streamlined bedrock hills and other landforms. Subsurface deposits and roots are commonly exposed by wind erosion. Wind can also reduce vegetation cover in wadis and depressions, scattering the remains of vegetation in interfluves. Stone pavements may result from the deflation removal of fine material from the surface leaving a residue of coarse particles. Blowouts erosional troughs and depressions in coastal dune complexes are important indicators of changes in wind erosion.
The potential for deflation is generally increased by shoreline erosion or washovers, vegetation die-back due to soil nutrient deficiency or to animal activity, and by human actions such as recreation and construction. Wind erosion also affects large areas of croplands in arid and semi-arid regions, removing topsoil, seeds and nutrients. HUMAN OR NATURAL CAUSE: Eolian erosion is a natural phenomenon, but the surfaces it acts upon may be made susceptible to active wind shaping and transport by human actions, especially those, such as cultivation and over-grazing, that result in the reduction of cover vegetation. Changes in vegetation cover can be monitored using historical records, sequential maps, air photos, satellite images, and by ground survey techniques.
Differential erosion by wind in the past may be detected through study of buried soil horizons developed on ancient erosional surfaces, which formed during dry wind erosion to wet soil formation climatic cycles. With an impact of up to 30 mph, rain washes out seed and splashes soil into the air. If the fields are on a slope the soil is splashed downhill which causes deterioration of soil structure. Soil that has been detached by raindrops is more easily moved than soil that has not been detached. Sheet erosion is caused by raindrops. Other types of erosion caused by rainfall include rill erosion and gullies. caused by rain and poor drainage.
Three types of erosion are: o Sheet erosion: Sheet erosion is defined as the uniform removal of soil in thin layers from sloping land. More specifically, it focuses on rill and inter-rill erosion and is not easily applied to areas where gully and stream bank erosion are widespread. Its universal nature has also been questioned particularly in terms of its application to tropical soils. Furthermore, it should be emphasised that this model does not consider the wide range of socio-economic and political factors which play a crucial role in terms of their influence on the degree of soil erosion which will be examined later. Alternative models include SLEMSA Soil Loss Estimator for Southern Africa and CREAMS Chemicals Run-off and Erosion Arising From Agricultural Management Systems.
Land use is perhaps the most significant factor influencing soil erosion, for two main reasons. First, many land use practices leave the soil devoid of a protective vegetation cover, or with only a partial cover, for significant periods of time and second, they involve mechanical disturbance of the soil. Specific aspects of land use often associated with accelerated soil erosion include expansion and intensification of arable cultivation, overgrazing, deforestation, certain forestry practices, site clearance in preparation for urban and industrial construction and a number of recreational activities such as walking and skiing.
Arable cultivation has expanded and intensified dramatically in recent decades. Relatively steep slopes, formerly covered by grass or tress, have been converted to arable cropping, while an increased use of heavy agricultural machinery has resulted in compaction of the soil. This, in turn, has led to reduced infiltration capacity, particularly along wheel tracks, thus resulting in increased surface run-off and erosion. Similarly, increased reliance on tillage activities, throughout the cropping cycle, has rendered soils more susceptible to erosion. This problem has been compounded by the decline in levels of soil organic matter and hence structural stability, largely in response to increased use of inorganic fertilizers.
In addition, the tendency to increase field sizes on arable land has meant that there are fewer physical breaks and barriers in the landscape, such as tree lines, hedgerows and walls, to restrict erosion. Susceptibility to erosion is further increased if land is cultivated with the slope rather than parallel to the contours. Overgrazing is particularly common in drought-affected parts of the developing world, such as the Sahel region of sub-Saharan Africa and the rangelands and communal lands of eastern and southern Africa. In a study of the impact of grazing on soils of the Savanna region of Nigeria, for example, Aweto and Adejumbobi attribute enhanced surface run-off and erosion to compaction of the soil and destruction of the protective vegetation cover by grazing animals and to the adoption of inappropriate burning strategies.
Deforestation, largely for logging and wood fuel purposes, is also common in many parts of the developing world. Trees are well-known for their ability to protect soils from erosion, particularly on steeply sloping terrain. Their root systems and the organic material which they supply help to stabilise the soil, while water uptake and canopy interception serve to reduce the frequency and intensity of surface run-off. In addition to deforestation, many forestry practices are associated with accelerated soil erosion, including the needle leaf forestry programmes which have become widespread in many areas of upland Britain. Here, erosion is most serious during the pre-planting stages of land preparation and drainage and after harvesting. In relation to urban and industrial land use, construction and associated disturbance of land may lead to increased soil erosion.
Even certain recreational activities have been implicated in this problem, including walking and skiing. A number of socio-economic and political factors have been associated with accelerated soil erosion, particularly in the developing world. These include population pressure, skewed land resource distribution; poverty and marginalization, increasing demand for wood fuel, inappropriate land tenure and farm policies, small size of land-holdings and poor infrastructure. In many developing countries, population growth is rapid and the demand for agricultural land and wood fuel is ever increasing Table Furthermore, agricultural systems are characterised by a skewed land resource distribution where a minority of affluent and powerful landowners control a majority of the land area.
The poorest farmers are thus forced onto marginal land, which is particularly susceptible to erosion, and often end up in a vicious spiral of debt. Rural-urban migration, abandonment of land and increased soil erosion are often responsible to this poverty trap situation Fig. In many parts of the developing world, large areas of land are utilised for mono-cultivation of cash crops, which are not necessarily best-suited to soil conditions, rather than for indigenous mixed food cropping. Such commercial pressure on agricultural systems, as well as contributing to the problem of marginalization discussed above, has a detrimental effect on soil quality and is unlikely to be sustainable in the long term.
There is also little political support in terms of education, training and incentive schemes to encourage farmers to adopt more sustainable land use practices. The establishment of appropriate and comprehensive soil conservation and land husbandry programmes is further hindered by the small size of land-holdings and the large number of farmers involved Table The on and off-site effects of soil erosion are considerable. At the global scale, it is estimated that unless soil conservation measures are introduced on all cultivated land, million ha of potentially productive rain-fed crop land will be lost and agricultural production expected to decrease by almost 20 per cent, by the year Undoubtedly, these effects will be felt most severely in those developing countries which are least able to cope with the problem.
It should be noted that the deterioration in soil productivity is disproportionate to the amount of soil eroded, as it is the nutrient rich and structure- supporting constituents in the topsoil which are lost most readily. Overcropping causes the soil to deteriorate when too many crops are grown on the same land without the farmer replacing lost mineral and organic material. In natural conditions, as plants grow, they extract the valuable mineral and organic plant nutrients from the soil; when they die, they decay and release their nutrients, returning them to the soil which is thus enriched for other plants that come after them.
But when men cultivate crops, they harvest them and carry the crops elsewhere to be sold or consumed. There is no replacement at all. If the farmer year after year, grows cotton which is very exhaustive of nitrates, and does not add any manure or fertilizers, the soil is bound to become poorer until the farm has to be abandoned. This is the growing of a single type of crop, year after year, such as cotton or wheat. The crop is constantly using up particular types of minerals from the soil which it needs. As a result some minerals in the soil may be completely exhausted and fertility may decline if fallow periods, fertilizers or crop rotations are not used to balance soil properties.
This is the constant use of the land for several crops every year. If there is not a constant supply of fertilizer this quickly exhausts the soil and yields rapidly decline. This type of cultivation of forest clearings can be very harmful. The destruction of the trees by fire means that the soil is no longer protected from the full force of heavy tropical rain, nor is it consolidated and held together by plant roots. It is therefore quickly washed away. After the ladangs are abandoned the forest is allowed to grow again, and, if the plot is not cleared again for a long time about 20 years , the rest or fallow period is long enough for the soil to regain its humus and mineral content. If, however, as usually happens, the plots are re-cleared after only a few years or one plot is occupied for too many years, the soil cannot recuperate and it becomes permanently infertile.
It may be eroded into deep gullies or invaded by lalang grass and is thus made useless either for farming or for forest. Animal grazing is dependent upon either natural or man-sown grasses and herbs, which are eaten by the cattle, sheep, goats or horses. The number of animals that can be grazed depends on the carrying capacity of the pasturage, that is the number of animals which can graze on the pasture without completely killing the grasses or other plants. If the number of animals is within the carrying capacity, the grass is able to grow again, but if there are too many animals it may not have sufficient time to recover and may be killed. If this happens the vegetative cover becomes too thin to protect the soil and rain and wind are able to erode the soil.
This in turn reduces the amount of grass that can grow in the area. In parts of Mediterranean Europe, West and East Africa and India, overgrazing by cattle, or worse still by sheep or goats which nibble down every bit of grass, has caused acute soil erosion. When men remove the natural forest cover of an area either for agriculture or for timber this usually exposes the area to soil erosion because the soil is no longer protected by the leafy canopy of the forest from heavy rain or strong winds. The bad effects of deforestation are worst when all the trees, even the smallest, are removed and when new seedlings are not planted to replace the felled timber.
Soil erosion is always enhanced when the cleared area of land is on a steep slope, because this allows gully erosion to take place. The soil on slopes, too, is easily moved by gravity when it is loosened. The effects of shifting cultivation, overgrazing and deforestation are all worse on steeply sloping land. Where cultivation takes place on steep slopes erosion is greatly aggravated if plants are arranged slope-wise, i. in rows up and down the hill slope. This practice of slope-wise cultivation produces ready-made channels down which rain-water can flow carrying away the topsoil. In semi-arid areas the cultivation of marginal agricultural lands may lead to erosion because the removal of the natural vegetation and the ploughing of the land loosens the soil and this enables the wind to blow it away.
This Soil Erosion Essay example is published for educational and informational purposes only. If you need a custom essay or research paper on this topic, please use our writing services. com offers reliable custom essay writing services that can help you to receive high grades and impress your professors with the quality of each essay or research paper you hand in. Soil is e s sental for life. It is the top cover of the earth and home to numerous plants and animals. In addition, it is a very important food and mineral resource for humans. The soil covering the surface of the earth has taken millions of years to form. Soil appears to last forever, but every day soil particles are loosened by a process called erosion.
Erosion is the displacement of solid particles from land, rocks, and minerals by the agents of water, ice, wind, and or gravity causing the soil to deteriorate. This process must be distinguished from weathering, which is the process of disintegration of soil and rock through direct or indirect contact with the atmosphere. One of the most important types of soil erosion is water erosion-the removal of particles from the land by water. There are four steps in the water erosion process. The first step is splash erosion, which is the movement of small soil particles caused by the impact of raindrops on soil.
The second step is sheet erosion, which is the result of heavy rain on bare soil where water flows as a sheet down any gradient, carrying soil particles; where precipitation rates exceed soil infiltration rates, runoff occurs and transports particles dislodged by the impact of raindrops. The third step is rill erosion, which results when surface runoff concentrates form small channels called rills. The fourth step in water erosion is gully erosion, which occurs when concentrated flows of water, formed by the coalescence of many rills, scour along a linear depression to create a trench or gully. Another important type of soil erosion is wind erosion-the removal of soil particles from the surface by the force of wind. Fine material can be transported and deposited over long distances.
This process of wind erosion, also known as eolian erosion, includes three stages that frequently occur at the same time. The first stage is suspension, which happens when fine soil particles are carried into the air and become atmospheric dust. The second stage is saltation, where dislodgement and movement of medium-sized particles is caused by their bouncing over the surface initiated by wind uplift and turbulence at the soil surface. The third and final stage is surface creep, where the largest or heaviest soil particles are rolled across the surface by wind force and by impacts from saltating processes. Soil erosion is a natural process that is often healthy for the ecosystem, but it has been increased by human activities that make it occur much faster than under natural conditions, contributing to soil degradation.
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