What is called soil erosion?
Soil is the basis of agriculture. It fulfills the basic needs of human beings such as food, fuel and fodder. Despite being so important, a neglectful approach towards soil conservation is adopted. Even if the government has tried to manage it, the expected target has not been achieved. As a result the soil is losing its fertility. Soil erosion is the loss of the top layer of soil. The loss of the top layer means that the soil becomes useless for all practical processes. Soil erosion is mainly caused by water and wind. If the velocity of water and wind is rapid, then the process of erosion is also rapid.
Define soil erosion- Erosion is the natural process in which the fragmentation of rocks and the consequent transfer of loose materials by water, wind, etc. Wind, water and glaciers and ocean waves are prominent in the processes of erosion.
Effects of salinity and alkalinity soil
- The structure of such soil becomes denser, which reduces the permeability of water in it.
- The supply of nutrients is interrupted.
- The toxicity of salts has an adverse effect on plants.
- Saline and alkaline soils can be made normal by the use of adequate irrigation, gypsum, sulphur, sulfuric acid, sorghum etc.
Types of soil erosion-
- General or Geologic Erosion: It is a gradual and prolonged process; In this, where there is a loss of the top layer or cover of the soil, on the other hand new soil is also formed. It is a natural process without any harm.
- Stream bank erosion: Streams and rivers change their course by cutting one bank and depositing the silt load on the other bank. The damage intensifies during severe floods. The Kosi river in Bihar has changed its course of 100 km in the last hundred years. moved to the west.
- Rapid Erosion: In this, soil erosion occurs at a much faster rate than formation. In desert or semi-desert parts where high velocity winds blow and in areas where there is heavy rainfall, this type of soil erosion occurs.
- Tubule Erosion: As the amount of surface water flowing increases, its velocity also increases on the slopes, resulting in the widening of the shallow streams into tubules. Later on, the ducts turn into wide ravines, which are 50 to 100 feet deep. The ravines are spread over an area of 10 million hectares of India.
- Snake Erosion: Snake erosion is born due to landslides. Huge masses of soil and obstacles arise in traffic and communication. The effects of snake erosion are local.
- Asphal Erosion: This type of erosion occurs as a result of raindrops hitting the exposed soil. In this process the soil gets crumpled and starts flowing in the form of mud.
- Layer Erosion: When a thick soil layer is removed uniformly from a surface area, it is called layer erosion. Soil movement as a result of asphal erosion is the primary factor in layer erosion.
- Small Stream Erosion: When flowing water loaded with soil weights flows along slopes, it forms finger-like systems. Stream erosion is considered to be an intermediate stage between layer erosion and tubule erosion.
- Coastal Erosion: This type of erosion is the result of the rapid action of strong waves.
Factors Affecting Erosion Rate
Climate: Excessive and prolonged rainfall causes heavy soil erosion. According to the Food and Agriculture Organization, the amount, intensity, energy and distribution of rainfall and changes in temperature are important determinants. The kinetic energy of rain is closely related to the nature of the soil. Temperature indirectly affects the rate and nature of soil erosion. The changing dry and moist conditions of the soil result in dehydration and hydration of the thin cover of the soil. This causes the soil particles to expand and cracks occur in the soil. Geo-Topographic Factors: These include aspects such as relative relief, slope, slope, etc. The flow velocity and kinetic energy of surface water are converted into deep gradients. Soil erosion is more extensive on slopes of longer length than on slopes of shorter length. The topography of the land determines over which surface the runoff will flow, which in turn determines the immaturity of the runoff. Longer, less steep slopes (especially those without adequate vegetation cover) are susceptible to much higher rates of erosion during heavy rains than shorter, less steep slopes. The steeper terrain is also prone to mudslides, landslides, and other forms of gravitational erosion processes. Natural vegetation cover: It is an effective controlling factor because
- Vegetation blocks the rain and protects the earth's crust from the direct impact of raindrops.
- By controlling the flow of rain water, vegetation allows it to seep into the ground surface.
- Plant roots reduce the rate of separation and transport of soil particles.
- Due to the effect of roots, there is an increase in granulation, soil capacity and porosity.
- Soil is protected from the harmful effects of high and low temperatures due to vegetation, due to which cracks do not develop in it.
- Vegetation reduces soil erosion by slowing wind speed.
Soil Nature: The erosion of soil is related to its physical and chemical properties, such as particle size, distribution, humus content, structure, permeability, root content, capacity, etc. Crop and land management also affect soil erosion. According to FAO, non-attachment, transport and molecular attraction of soil particles and moisture holding capacity and depth of soil are important factors influencing soil erosion. Development: Human land development, in forms including agriculture and urban development, is thought to be an important factor in erosion and sediment transport. In Taiwan, an increase in sediment load in the northern, central and southern regions of the island can be observed along the development timeline for each region in the 20th century. Wind Velocity: Strong and strong winds have great potential for erosion. Thus wind velocity has a direct relational relationship with the intensity of erosion.
Due to soil erosion-
- Deforestation: Deforestation increases the rate of erosion by removing mineral and soil layers from the soil surface, removal of vegetation cover that binds soils together, and mineral erosion due to heavy soil compaction from logging equipment. Is. Once trees are removed by fire or logging, infiltration rates become high and erosion occurs to lower levels of the forest floor. The loss of vegetation cover has given rise to extensive erosion in the Western Ghats, Uttar Pradesh and Himachal Pradesh.
- Wrong farming practices: Potato and ginger crops are grown in the Nilgiris region without taking anti-erosion measures (building steps on slopes, etc.). The forests on the slopes have also been cleared in order to grow plant crops. Due to this type of faulty farming practices, soil erosion accelerates. Landslides become a common symptom in these areas.
- Jhum Agriculture: Shift farming is an ecologically destructive and uneconomical farming method. Jhum agriculture is used especially by the tribes in the hilly regions of North-East Chotanagpur, Odisha, Madhya Pradesh and Andhra Pradesh. Due to shifting or shifting agriculture, a large area in the north-eastern mountainous areas has become a victim of soil erosion.
- Transformation of natural drainage systems for the construction of railways and roads: Rail tracks and roads should be laid in such a way that they are at a higher level than the surrounding land, but sometimes railway tracks and roads are in the path of natural drainage systems. become an obstacle. This creates the problem of water revolution on one hand and water scarcity on the other. All these factors contribute to soil erosion in one or more ways.
- Lack of proper surface drainage: In the absence of proper drainage, waterlogging occurs in low lying areas, which loosens the top soil layer and makes it prone to erosion.
- Forest fires: Sometimes forest fires occur due to natural reasons, but human-caused fires are relatively more destructive. As a result, the forest cover disappears forever and the soil suffers from the problem of erosion.
Effects of soil erosion-
- Flash floods.
- Change of water current due to accumulation of sand in the course of rivers and many types of losses due to it.
- Destruction of fertile agricultural land.
- The loss of the fertile top layer of the land due to cover erosion.
- Decline in water for drinking and irrigation due to fall in ground water level.
- Expansion of dry desert has adverse effect on local climate and indirectly on agriculture.
- The problem of timber and firewood due to destruction of vegetation cover and adverse effects on wildlife.
- Destruction of roads by landslides, etc.
Ways to reduce soil erosion-
Improvement of existing surface cover: This type of improvement is possible only by preserving the soil cover by growing cover crops like Barsi (a fodder crop) or grasses like Doob, Kuju, Dinanath etc. Striped Farming: Under this, crops supporting erosion (sorghum, millet, maize etc.) are grown under alternate belts with anti-erosion crops (grasses, pulses etc.). Anti-erosion crop belts stop the flow of water and soil. Crop rotation: Under this, two or more crops are grown sequentially in the same field so that the fertility of the soil can be maintained. Soil erosion intensifies when clearly attracted crops (tobacco etc.) are grown continuously. A good crop rotation should include heavily planted small cereal crops and leguminous plants (which can control soil erosion). Stubby mulch: It refers to the leaving of crop and vegetable stubble on the ground to protect the soil layer from soil erosion. Plumped mulching reduces evaporation and increases seepage capacity, resulting in conservation of soil moisture. Use of organic fertilizers: The use of green manure, cow dung, agricultural waste, etc. improves the soil structure. The friable and friable soil structure increases the permeability and permeability of the soil and helps in the conservation of moisture. Other measures may include control over overgrazing, reduction of pet surplus, ban on shifting cultivation and prevention measures against forest fires.
Physical or Mechanical Measures:
- Stepping: A series of steps and flat platforms should be made on steep slopes, so that water can be collected at each step or platform and used for crop growth.
- Construction of proper drainage channels and filling of ducts.
- Contour Traction: All types of traction actions on sloping land should be done at proper angles to the slopes, this allows a sufficient amount of flowing water to be collected in each groove, which is absorbed by the soil.
- Contour bandha: Under this, the slope of the land is divided into smaller and more horizontal cells. To do this, contours as well as suitable sized physical structures are created. Thus, each bandh stores rainwater in different chambers.
- Basin listing: Under this, small basins or troughs are created at regular intervals on the slopes, which help in controlling the watershed and conserving the water.
- Water Harvesting: In this, efforts are made to store or flow water in low-lying areas, which helps in controlling the flow as well as preventing floods.
- Scientific slope management: The cropping activities on the slopes should be in accordance with the nature of the slope. If the slope ratio is between 1:4 to 1:7, then proper cultivation can be done on it. If the above ratio is more, then pastures should be developed on such sloping land. The forestry activities should be spread on the land with even higher slope ratio. For any type of cropping activity on slopes of very high proportion, the construction of steps or altars becomes necessary.
Areas of Soil Erosion in India
At present, the problem of soil erosion has become a major problem of Indian agriculture. Every year 5 billion tonnes of soil is eroded in the country. On the basis of the main causes of soil erosion, India is divided into the following regions. North-Eastern Region (Assam, West Bengal, etc.): The main causes of soil erosion are heavy rainfall, floods and widespread erosion of river banks. Shivalik ranges of Himalayas: The first reason is the destruction of vegetation. Flooding of rivers due to siltation is another important reason. River banks (Yamuna, Chambal, Mahi, Sabarmati, etc.): The conversion of a large part of the agricultural land of Uttar Pradesh, Rajasthan, Gujarat and Madhya Pradesh into ravines is the result of soil erosion. Mountains of Southern India (Nilgiris): In the southern mountainous region, intense soil erosion can be caused by steep slopes, heavy rainfall and improper farming practices. Arid region of Rajasthan and southern Punjab: In some parts of Punjab and Rajasthan, such as Kota, Bikaner, Bharatpur, Jaipur and Jodhpur, soil erosion is caused by wind.
The rapid pace of soil erosion in India can be reduced by the following measures and at some places it can also be completely controlled-
- Planting trees and not destroying the trees completely.
- Build dams and make huge reservoirs to control floods.
- Build a terraced field on the mountains and plow across the slope.
- Controlling cattle feed.
- Leaving agricultural land fallow to a minimum.
- Growing crops by swapping them.
- Line up forests to control deserts.
- Proper use of manure and fertilizers to maintain the same fertilizer capacity of the land.
- Developing a permanent agricultural area, because in shifting agriculture, forests are cleared.
Some amount is allocated in various five year plans to implement the program of soil conservation in India. In the first five year plan, 10 regional research and training centers were opened across the country for the work of conservation of land. In 1952, Desert Plantation and Research Center (Kajri) was established in Jodhpur district of Rajasthan. This center plants suitable saplings in the desert and from here the saplings and seeds are distributed for growing. Since the first plan till now, several crore rupees have been spent for this program and several lakh hectares of land has been protected, but there is still a need for improvement.
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