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Erosion

  • What is erosion?
  • Erosion, also called erosion (washout, denudation, attrition, dilapidation), is the phenomenon that the soil above the earth’s crust is eroded and displaced from its place, transported from one place to another, and accumulated, with various external factors, mainly rivers.

 

  • 70% of the land used in agriculture has lost its characteristics and caused about 30% desertification on total land worldwide. There are 110 countries in the world where there is a danger of desertification due to erosion. In this context, the United Nations Environment Program estimates that 42 billion dollars a year have to be spent to prevent desertification and erosion in the world.

 

  • The fertile lands lost in natural conditions can be compensated by natural cycles … Erosion can reach dimensions that can not be compensated by unconsciousness and human influence. The fertile lands lost due to the effect of erosion cause the decrease of the agricultural production capacity. The formation of erosion takes place with natural factors, but the fact that erosion causes irreparable damage occurs when people accelerate these factors.

 

  • Water erosion, one of the erosion types, is the most effective erosion. Besides erosion of rain drips in this erosion, there is a significant effect on surface waters. Wind erosion, another type of erosion, is the erosion and transport phenomena caused by the wind.

 

  • The erosion leads to the loss of fertile lands and leads to the formation of fairy chimneys, causing a natural beauty to come to fruition, creating tourism zones and creating a contradiction. Protected column erosion, which is a type of special erosion at the end of many years, causes these occurrences.

 

  • Causes of erosion
  • The causes of erosion formation are some natural factors. With another discourse erosion is a natural phenomenon that has taken place since the establishment of nature. This natural erosion can be counterbalanced by soil formation by nature. However, the erosion that occurs naturally can increase in the way that nature can not meet with the influence of people. This type of erosion is called “accelerated erosion“.

 

  • As can be understood from the definition of erosion, the most important cause of erosion is to increase the effect of the factors that can affect the erosion of the soil. The transport of weak land in terms of vegetation is quite easy.

 

  • The wind, surface runoff and irrigation waters are closely related to the existence of vegetation that gravity can combine with the slope to transport the land. The plant cover may prevent transport by forming a set in front of the soil parts, despite the tendency to soil. Reducing the effects of wind and rain drops can slow down wear and tear.
  • erosion1
  • Plants have an important place in preventing erosion

 

  • One of the most important reasons of erosion is ignorance. Especially in agricultural land, the erosion increases without consciousness. The incineration of stubble in agricultural land causes short-term crop growth. As a result, the farmer who does not have sufficient information may cause erosion indirectly by damaging the soil structure and living creatures by burning the stunts and may cause the soil to be transported by gravity, water or wind by driving the field in the direction of the slope. In forest fires, natural vegetation and the disappearance of living organisms cause erosion to increase.

 

  • Particularly, the burning of forests in mountainous areas has more effect on erosion.

 

  • Erosion can also occur with streams, streams or lakes outside of precipitation. For example, rivers can carry soil to another place by eroding the soil due to the abrasive power of the water. The soil can be transported with floods after heavy rainfall.

 

  • Water abrasion power is quite high. For example, a large part of the seaside rocks are rounded. This is not because the stones are not hard enough, but because the water has a high erosion power. Soil erosion can be the main cause of the earth. Sandy soils that we can easily see on the beach can cause erosion due to erosion resistance.

 

  • Soil formation and erosion effects
  • Soil properties have also a significant impact on erosion. Factors affecting soil formation also affect soil properties, increasing the probability of erosion. Soil formation has five different effects on erosion.

 

  • Time is one of the factors that are effective in soil formation. The same amount of time is not needed to form each soil. While some land takes longer, shorter time is sufficient for some. For example, soil forms in a shorter time than the soft base material. The rate of formation increases as the depth of soil decreases in soils that are subjected to erosion. The increase in soil depth from such soils depends on the balance between the rate of erosion and the rate of its formation. According to this;

Formation speed > If the rate of ablation is Depth increases
Formation speed < Velocity of abrasion, Depth is reduced
Formation speed = Ablation speed, Depth does not change

 

  • The second most important factor in soil formation is the climate factor. Climate events can affect the rate of soil formation as well as the extent of abrasion and soil type. For example, in the formation of soil by the effect of rainfall, a part of the water falling into the soil penetrates into the soil, and a part of the water passes into the surface stream. Water leaking into the soil is affected by soil formation and erosion as a result of washing along the profile. In areas with hot and low rainfall water abrasion is low. Wind erosion occurs in places that are hot and arid or cold and arid.

 

  • Topography and drainage, Besides climate effect, topography and drainage are also important influences. Slope, elevation, etc. in the ground. All factors, both precipitation and gravity, are factors that influence the transport of the soil of that zone. This transport will directly affect the erosion and depth of the soil as well as the erosion of the lower layers of the soil and the formation of the soil. All these factors show the effect of topography and drainage on erosion.

 

  • Living creatures are one of the important factors that affect the formation, abrasion and erosion of soil in the country. Micro- and macro-organisms accelerate soil formation with their secretions or movements in soil formation. The acceleration of soil formation increases soil depth. The presence of living things that have indirect effects on soil formation and erosion in this framework has an important place in combating erosion. For example, incineration of stubble in agriculture causes soil microorganisms to die and prevents soil formation. At the same time, the reduction of the numbers of these creatures does not make it possible to transform the plant nutrients in the soil into useful forms for plants. As a result, plants die by not utilizing nutrients. The soil opens up in front of erosion.

 

  • The main material in the region where the soil is formed, is another important factor affecting the kind of soil and erosion resistance. In other words, the parent material very significantly affects the properties of the soil to be formed. For example, the soft limestones form rendzina soils and the hard limestones form terra rosa soils. Rendzina soils are more susceptible to erosion and terra-rosa soils are more resistant.

 

  • Types of Erosion
  • Water erosion
  • The most intense erosion type. When water soil is worn and viewed from the point of view of transportation;
  • Drip erosion
  • Surface flow erosion
  • Groove erosion
  • Storm erosion
  • Erosion caused by river beds

 

  • Grand_Canyon_Horse_Shoe_Bend
  • Horseshoe Bend, a fold formed by water erosion in Arizona.

 

  • Drip erosion, erosion that occurs when the drops fall during the precipitation, soil erosion and the current energy and the earth spatter. These splashes can be up to 60-100 cm up to 60 cm. This type of erosion is the most severe erosion and transport erosion. The fact that soils are covered with vegetation is one of the most important factors in preventing this erosion. The factors affecting drop erosion are as follows.
  • Shape angle
  • Splash angle
  • Crater width
  • Drop height

 

  • If there is a layer of accumulated water on the surface, the splash angle shrinks and an angle of about 85-90 degrees occurs. This erosion type is more effective than flowing water, although there is an erosion that is effective at the beginning of the rain. The diameter of the drop is also directly proportional to the damage it gives. By way of example, a rainfall of 2 mm in diameter can blow a land weighing approximately 40 g by 1 cm when hit at a limit speed.

 

  • This erosion causes the formation of an impermeable layer on the surface by compressing the soil with the effect of rainfall.

 

  • Surface flow erosion is the type of erosion that is created by mixing non-infiltrating water with particles and ground aggregates passing through the surface stream. Surface flow erosion is not always observable, especially when the soil color is dark, making it difficult to observe.

 

  • Groove erosion, Continuation of surface flow increases erosion and gouges after a certain stage. Through the grooves formed, the erosion continues by accelerating. This type of erosion is called “Groove erosion“.

 

  • Grain erosion (Gully) After the progression of the gutter erosion, the gutters begin to become wider and deeper. Compared to the gutters, there are bigger contractions and this erosion is called erosion of the erosion. The erosion of the erosion is examined in three ways according to its shape.
  • U-shaped contest
  • V-shaped arguments
  • Step-wise contest

 

 

 

 

 

  • The erosion created by river beds, River deposits erodes the beds deeply and expansively. This erosion is called “Erosion of Stream Beds.” The erosion depends on the flow of the stream. The transport of material in this type of erosion occurs in three ways.

 

  • Wind erosion
  • The consequence of wind erosion is the loss of fertile soils, accelerated evaporation, the reduction of soil moisture, the slowing of plant growth, the lack of transportation and the drop in efficiency. Transported sand and inefficient soil cover productive agricultural land, making agriculture impossible. Wind erosion is the most severe; It is seen in Central and Eastern Anatolia that the vegetation cover is poor and the climate is dry. Wind erosion is very effective in places where vegetation cover is not excessive. Wind erosion occurs in three different ways. These,
  • Flying with airflow
  • Surface drift
  • Splash
  • Flying with air currents The soil particles whose diameter is less than 0.1 mm by the influence of the air current rise from the surface and act by the influence of the wind. In this way, the soil particles rising from the surface will fly to different zones than the places where they are, causing soil to be transported. In this way, the pieces of soil that are carried can be transported for hundreds of kilometers. The most important factor in preventing this kind of transport is vegetation cover. As the vegetation will reduce the effect of the wind, it prevents the parts of the soil from slipping away.

 

  • Drift on the surface, moving due to the effect of the wind, but due to their size can not rise more than the surface of the soil particles are drifted on the surface. The diameter of the soil carried in this way is between 0.5 mm and 1 mm. Spattering of lands carried by jumping causes the speed of these soil particles to increase. At the same time, the collision parts are reduced in diameter and their transport is facilitated.
  • Splash, Some parts of the earth rise with the effect of the wind and start to rise in the direction of the wind. If these pieces of land are not as small as the pieces flying by the air current, they fall downwards after a certain height, when the winds lose their effect. In this way, if the soil is transported by continuous splashes, it is referred to as jumping transportation. The soil diameters exposed to this type of wind erosion are between 0,1 mm and 0,5 mm.

 

  • Special types of erosion
  • In addition to the effects of water, wind and other corrosive factors, they are erosions that occur under special conditions. It is expected that more than one condition exists for these erosions to take place.
  • Tunnel erosion, When there is a soil layer stuck in the upper part, under the top soil layer wrapped by dense plant roots, if there is a saturated layer with water, there is a wear under the soil.
  • After this erosion, a tunnel-like gap is formed under the soil to protect the state of the stuck soil at the top. The erosions formed in this way are called tunnel erosion.
  • Sharp hill erosion = The eruptions on the volcanic hills are the resultant sharp hills.-
  • In this type of erosion, the effect of wind is important. With the wind effect, erosion occurs on the tops. As a result of this eruption, the sharpened peaks come to the fore. The main reason why the hills have a sharp appearance is the rock that forms the hill.

 

  • Protected column erosion = very severe abrasions in volcanic fields. As the flood waters descend from the slopes, they erode the rocks there. Some of the hard rocks in the upper section do not erode and allow undeveloped areas along the column to be formed. Parts that do not have hard rock on it start to wear out. Hard rocks on the erosion columns formed in this way can be observed easily. Fairy chests are the best example of this erosion.

 

  • Mass movements = movements that occur with the participation of the gravitas in the water. The movement of some pieces of soil from mountains or sloping areas by moving in the direction of gravity.

 

  • Factors affecting erosion
  • We can collect factors affecting erosion under 5 groups. These are Climate, Topography, Soil Properties, Plant Cover and Human Factor. Four other factors outside the human factor are defined as natural erosion factors.

 

  • Climate
  • It acts as rain, wind and temperature. The kinetic energy of precipitation is the most important factor in abrasion. Rainfall-like rainfall, snow and full impact differently. The most important effect is the rain. The effect of climate on erosion can be examined 4. These;
  • The density of precipitation,
  • The duration and distribution of precipitation,
  • The effect of the wind,
  • The temperature.

 

  • Precipitation density, density in precipitation erosion is considerably effective. In this context, rainfall intensity is the amount of rainfall per unit time. As the precipitation density increases, the amount of water falling to the soil increases and the infiltration rate of the soil decreases more quickly. The infiltration values ​​of soils vary depending on whether the soil has been treated or not. Since the natural vegetation has been destroyed in the treated soil, the infiltration power of the soil is exceeded more quickly. Infiltration takes a long time if the soil surface is protected. Understanding the effect of rainfall intensity can be explained in another town. For example, if a sponge is slowly drained out of the sponge, the sponge will be easily absorbed. This way the water will not leak out.

 

  • However, if the water is poured on the sponge at the same amount, the water will not be absorbed by the sponge and will flow into the sponge. If the ability to penetrate the soil into the water is considered to be genius slower than the bayonet, the effect of the rainfall intensity on erosion will be clearer.
  • The duration and distribution of precipitation, as well as the density of precipitation, is an important influence on erosion. The longer duration of two precipitation rains at the same density causes more erosion. It is important for the distribution of precipitation in terms of erosion. The precipitation distribution can be in a precipitation or seasonally and in the form of annual dispersions. There may be a four-part rainfall distribution in a precipitation. These include: continuous precipitation (uniform rainfall distribution) throughout the whole precipitation, heavy rainfall (heavy rainfall distribution), low rainfall intensity increasing rainfall (rainfall distribution), low rainfall intensity (medium rainfall distribution) Precipitation (Delayed precipitation distribution). The most effective of these is the distribution of advanced precipitation. The distribution of precipitation within a year,
  • Uniform rainfall: Rainfall falls every month in a year.
  • Uni-model precipitation: Months of precipitation fall in one half of the year.
  • Bi-model precipitation: Monthly precipitation in the second half of the year.
  • The effect of the wind, the rate of falling rain drops and the angle of impact on the soil surface. There is also an effect on the surface flows that occur in windy weather. For example, the wind blowing in the opposite direction to the exit of the basin allows the surface flow to leave later. All of this affects erosion by increasing abrasion and transport. There is an erosion effect on the wind as much as the effect of water erosion.

 

  • Temperature affects the events of decomposition and disintegration of vegetation cover. Where the temperature is high, the organic matter breaks down rapidly. As a result, aggregation is reduced. Plant cover is diluted. These are factors that increase erosion. In areas where the temperature is not rainfall, it causes the drought and hence the effects of wind erosion to increase. So the temperature is a sign that interacts with other factors.

 

  • Topography
  • Topography is one of the factors that influence erosion. Topography affects water erosion 6. These;
  • Tilt stitch
  • Slope length
  • Micro-relief
  • Sloping

 

  • Pitch stiffening increases the speed of surface runoff water and increases wear. Increasing the amount of surface runoff increases the amount of worn-out soil.

 

  • The slope length increases, in general, as the slope length increases, the wear and the amount of soil carried. But in some cases there may be differences depending on rainfall intensity and soil permeability. Increasing the slope length in low-density rainfall and high-permeability soils may lead to a decrease in erosion.
  • Micro-relief (ruggedness), roughness of the soil surface, water storage reduces erosion effect

 

  • There are four different types of slopes in the shape of slopes, on the earth, these are flat, convex, concave and wavy slopes. Outer convex shapes are the most effective of erosion from these surface shapes.

 

  • The larger the basin size and shape, the larger of the two similar two-storey basins, the more erosion occurs. Beside the size of the basin, the basin is important in terms of shape erosion. The surface waters may be more easily abandoned in one of the two basins whose sizes are the same but their shape is different from basin exit locations, while others may not be able to leave. The effect of erosion from later abandonment is less.

 

  • Direction, the direction of the land indirectly affects the temperature. In the northern half-sided north-facing slopes, vegetation is more dense, organic matter accumulates more. Soil is high in moisture. On the southern slopes, the sun’s rays are more steep, so the opposite situation occurs.

 

  • Soil properties
  • Soil properties are divided into physical properties and chemical properties.
  • Effect of physical properties
  • Percent skeleton: (?) The percentage of parts over 2mm nin forms the percentage of the skeleton. Increase in the percentage of soil skeleton increases resistance to erosion.
  • Especially the dust on the surface protects the underlying soil materials.
  • Soil area: The composition of soil, sand, shaft, clay constitutes the soil. The excess of sand from the parts making up the soil increases the effect of erosion. The excess of the kiline reduces the effect of erosion as it increases aggregation. Some ratios are used to determine the resistance of the soil to erosion. These percentages are obtained by multiplying the percentage of clay by percentage of the sum of the percentages of shafts and sand. The smaller the ratio, the higher the erosion resistance. In general, if the shaft ratio of the soil is less than 2.5%, it is expressed as durability and above it as durability.
  • Water holding capacity at different pressures: Hygroscopic water in soil, water suspended around soil collars. The higher the hygroscopic water, the higher the amount of kalloid in the soil. The higher soil kalloids indicate that the soil is resistant to erosion.
  • Effect of aggregation: Aggregation improves some physical properties of soil and increases efficiency and resistance to erosion.
  • Influence of air and water permeability: Increasing water permeability in particular causes increased water penetration into the soil and reduced water flow to surface flow. Air and water permeability are related to the gaps in the soil. Therefore, the presence of voids in the soil increases the resistance to erosion.

 

  • Effect of chemical properties
  • Calcium carbonate (Lime) Effect: Calcium is an essential element for both plant breeding and clustering. Thus providing a preliminary stage of aggregation. Where wind erosion is effective, it gives the calcareous soils a dusty structure, which makes it easier to move the soil with wind and reduce erosion resistance.
  • Impact of Cation Exchange Capacity (CEC) and Exchangeable Cations: It is a characteristic of organic and inorganic carboids in the soil. The elevation of the CEC shows that the amount of these kalloids is high. In these cations the erosion is affected in different ways. For example, in Ca and Mg exchange capacity, the resistance to water erosion increases. On the other hand, Na and H are low and aggregation is low.
  • Organic Effect: The decomposed or partially decomposed organic matter on the soil surface protects the soil surface against rain drops. The grown plant species has an effect on the organic matter content of the soil. The O and N losses from the square are affected. The least loss of organic matter occurs in the planting system at different times.

 

  • Flora
  • As in the organic matter, the rain on the soil surface reduces the impact of rain drops. It prevents the formation of the slippery layer on the soil surface. More water infiltrates into soil. The type of plant cover on the surface also affects the soil erosion. From the vegetation cover that protects the soil to the least, the protection can be ordered as follows;

 

  • Continuous vegetation (protected forests, continuous meral and meadow cover)
  • pulse
  • Small seeded legumes
  • Cereals (Wheat, Barley, Oat etc.)
  • Anchovy plants (Tobacco, Potato, Maize, Soya etc.)
  • In this order, the anchor plants seem to have protected the land at least. For this reason, care must be paid to soil and water conservation precautions when an anchorage plant is being cultivated in sloping land.

 

  • Human factor on erosion
  • The human factor is the most important factor affecting erosion. Because the human factor does not only cause erosion but also causes other factors to change, which can lead to the erosion of the balance. The human factor,
  • To destroy the natural vegetation cover,
  • To break up forests to open land or to obtain fuel,
  • The use of metamorphosis on capacity,
  • To use the place outside purpose,
  • Attention to soil and water conservation measures,
  • Make the wrong version.
  • Erosion for a variety of reasons such as.
  • Erosion retarding measures
  • It is possible to reduce the amount of erosion and attract it to acceptable limits depending on the precautions to be taken. For this, precautions should be taken according to the type of erosion.

 

  • Slowing measures of water erosion
  • Reducing the impact of rainfall on the soil surface,
  • To create a deciduous plant cover that can last for a long time.
  • Prevention of decomposition and dispersion of soil aggregates,
  • Reduce the use of tools and machinery that break down the soil.
  • Increasing the rate of infiltration,
  • Reduction of surface flow rate
  • Increase of infiltration and reduction of surface flow by breakage of hard soil layers in agricultural land.

 

  • Slowing measures of wind erosion
  • Reducing wind speed,
  • Equipping the area with trees that will break the wind speed.
  • To make movement difficult by the effect of gravity on the veil,
  • To make a steep version of soil processing operations.
  • To reduce the effect of the wind on the soil particles,
  • Do not leave the surface of the soil naked.
  • Use the land by bringing it up the stairs.

 

  • Terraining in sloping land
  • Peru-terrain

 

  • Construction of terraces in sloping terrain is also an important precaution in the context of slowing erosion. Roof terraces, back terraces and terrace terraces, which are separated by coins, prevent the waters from congregating soil pieces together. Channel terraces can be successfully applied in areas with 4% ‘eccentric inclination, while back terraces have succeeded when applied in areas around 2%. The most important difference between the back terraces and the canal terraces is that the back terraces can also provide water conservation as well as soil conservation in areas where there are few water springs. Seki terraces are used as slopes in more than 12% slope soils. This type of terrace is not suitable for the use of mechanization in agricultural activities.

 

  • Heavy rains should be prevented from seeing the end damage so that the terraces can function. For this reason, germinating these areas after terracing is important for the terraces to protect the structure. If an agricultural activity is carried out in the terraced area, the versions shall be either planed or the version parallel to the terrace backs should be preferred in the flat version.
Erosion
Author: wik Date: 11:10 pm
Geography


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