Soil Erosion: An Introduction
We all are aware that soil is one of the most important factors in the production of food for both animals and humans. Plants also depend on soil for their nutrition and survival. Soil is a mixture of organic matter, minerals and weathered rocks found on the earth. The major factors of soil formation are the nature of the parent rock, climatic factors, topography, the role of organic material and time taken for the composition of soil formation which differ from place to place.
Different Layers of Soil
Besides these, human activities also influence the quality of soil to a large extent. Processes such as deforestation, overgrazing, overuse of chemical fertilisers or pesticides, rain wash, landslides and floods decrease the quality of the soil. This degradation of soil, due to several factors is known as soil erosion.
In this article, we are going to learn about soil erosion, its causes, its impact on our day-to-day life and the prevention of soil erosion.
What is Soil Erosion?
The removal or destruction of soil cover due to subsequent washing by water, wind or ice is known as soil erosion.
Soil Erosion of a Piece of Land
The process of soil formation and soil erosion occurs at a simultaneous rate and there is a balance between them. But sometimes, this balance is disturbed due to factors which include human activities like deforestation, overgrazing, construction and mining etc., and natural forces like wind, glaciers and water. These disturbances make the land unfit for cultivation and consider it bad land.
Types of Soil Erosion
There are different types of soil erosion depending on the natural process that causes it. They are explained as follows:
Sheet Erosion – In sheet erosion, a large wave of water flows as a sheet over large areas down a slope. It usually takes place on level lands after a heavy shower where the soil removal is not easily noticeable. Sheet erosion is more harmful since it removes the finer and more fertile topsoil.
Wind Erosion – In wind erosion, the wind blows loose soil off flat or sloping land.
Raindrop Erosion – In raindrop or splash erosion, the erosion is due to the impact of falling raindrops on the soil surface which causes the destruction of the crumb structure.
Gully Erosion – In gully erosion, gullies which deepen due to rainfall cut the land into small fragments and make it unfit for cultivation. It is usually common on steep slopes.
Causes of Soil Erosion
There are several causes of soil erosion and some of them are given below:
Loss of Vegetation – The roots of plants are firmly bound to the soil. But due to the absence of vegetation on the soil, it can be moved by wind and flowing water. Thus, soil erosion is more severe in areas with little or no surface vegetation, such as deserts or bare lands.
Defective Methods of Farming – Improper methods of farming such as ploughing in the wrong way i.e. up and down the slope form channels for the quick flow of water leading to soil erosion.
Wind – Wind is a powerful natural process which causes soil erosion because of its ability to remove soil and transport it. Erosion due to the wind is significant in arid and semi-arid regions.
Water – Erosion due to running water is significant in regions with heavy rainfall and steep slopes. Water erosion is more serious and occurs extensively in different parts of India, taking place mainly in the form of sheet and gully erosion.
Increasing population – Due to the increasing human population the demand for land also increases. Forest and other natural vegetation are removed for human settlement, cultivation, grazing animals and for various other needs. Thus, this is also a significant cause of soil erosion.
Effects of Soil Pollution
The most common effects of soil pollution are given below:
Soil pollution causes a decline in the number of useful bacteria and fungi in the soil which leads to plant damage.
Crops grown on polluted soil will result in the production of unhealthy food and thus affect human health.
Soil pollution also degrades the soil quality and eventually, the soil loses its fertility.
Impact of Soil Erosion
Soil erosion has a serious impact on Indian agriculture and its negative effects are seen in other spheres also. There are large areas of arable land in the irrigated zones of India that are becoming saline because of over-irrigation. The salt lodged in the lower profiles of the soil comes up to the surface and destroys its fertility. Chemical fertilisers in the absence of organic manures are also harmful to the soil as unless the soil gets enough humus, chemicals harden it and reduce its fertility. This problem is very common in all the areas of the river valley projects, which were the first beneficiaries of the Green Revolution. According to estimates, about half of the total land of India is under some degree of degradation. Every year, India loses millions of amounts of soil and its nutrients to the agents of its degradation, which adversely affects our national productivity.
Prevention of Soil Erosion
In order to prevent soil erosion, there are some methods that can be used are explained below:
Mulching – In the mulching method, bare ground between plants is covered with a layer of organic matter like straw which helps to retain soil moisture.
Contour Barriers – A contour barrier means building a barrier with stones, grass, and soil along contours. Trenches are made in front of the barriers to collect water.
Rock Dam – In the rock dam method, rocks are piled up to slow down the flow of water which prevents gullies and further soil loss.
Terrace Farming – Terrace farming is a farming method in which steep slopes are made so that flat surfaces are available to grow crops. This reduces surface run-off and soil erosion.
Intercropping – In intercropping, different crops are grown in alternate rows and are sown at different times to protect the soil from rain wash.
Contour Ploughing – Contour ploughing is done by ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down the slope.
Shelter Belts – In the coastal and dry regions, rows of trees are planted to check the wind movement to protect soil cover.
Interesting Facts
The damage caused by soil erosion in a year costs around 400 billion dollars.
Soil erosion causes the plant productivity to fall by 10% every year.
Important Questions
1. What is soil erosion? Explain its causes.
Ans: The process of removal of soil cover is known as soil erosion. The causes of soil erosion include the defective methods of farming and loss of vegetation.
2. What are the effects of soil erosion?
Ans: The effects of soil erosion include - land degradation, low crop quality and number of microbes.
3. How can we prevent soil erosion?
Ans: Soil erosion can be prevented by mulching, contour barriers, shelter belts etc.
Key Features
Soil erosion is defined as the removal or destruction of soil cover due to subsequent washing by water, wind or ice.
It is of different types which include sheet erosion, wind erosion, gully erosion and raindrop erosion.
There are several causes of soil erosion which include loss of vegetation, wind, water, increasing population etc.
Soil erosion has a serious impact on agricultural practices. It reduces the fertility and nutrition quality of the land making it degraded and unfit for use.
Every year we lose a large amount of soil due to soil erosion. There are some preventive measures for reducing soil erosion including mulching, terrace farming, intercropping, contour ploughing, shelter belts etc.
FAQs on Soil Erosion
1. What is soil erosion? Name its different types and methods to prevent soil erosion.
Soil erosion is a process of removal of soil cover due to subsequent washing by water, wind or ice. It includes four types which are Sheet erosion, wind erosion, raindrop erosion and gully erosion. In sheet and raindrop erosion, water causes the removal of soil cover and in gully erosion, water and wind both cause the removal of soil erosion. There are some preventive measures for reducing soil erosion including mulching, terrace farming, intercropping, contour ploughing, shelterbelts, contour barriers etc.
2. How does the process of soil erosion work?
The process of soil formation and soil erosion occurs at a simultaneous rate and there is a balance between them. But sometimes, this balance is disturbed due to factors which include human activities like deforestation, overgrazing, construction and mining etc., and natural forces like wind, glaciers and water. These disturbances make the land unfit for cultivation and consider it bad land. Soil erosion causes a serious impact on agricultural practices and as a result, crops and vegetables get destroyed leading to big destruction of food.
3. Why is it important to prevent soil erosion?
It is very important to prevent soil erosion because of
Soil fertility - Due to soil erosion, soil loses its fertility which leads to less production of crops and thus less food.
Essential nutrients - The major effect of soil erosion is that the soil loses essential nutrients which require years to regain.
Important microbes - Soil erosion reduces the number of microbes such as fungi and bacteria in the soil which help in plant growth, good quality crop production and maintaining the pH of the soil.
4. What is grazing?
The grazing animals prey on the grasses and take away the vegetation from the land. Their hooves disgust the soil. They also pull out plants by their roots. This loosens the soil and makes it more vulnerable to erosion. Grazing is basically a method to raise domestic animals. These animals are left on farms to roam and consume the natural vegetation. Due to this, the top layer of the soil gets more prone to erode with the grass they eat.
5. How to prevent soil erosion?
Some of the ways to prevent Soil Erosion are -
Plant trees on unfruitful lands to limit erosion of soil.
Add mulch and rocks to prevent the plants and grass underneath to prevent erosion .
Mulch matting usually won’t reduce erosion on the slopes.
A wall at the rock bottom of the slope can help in preventing the soil from eroding.
Every household should have an accurate waste management system in order that water flows down into proper water collecting systems.
