Soil erosion is the detachment of soil particles from one place to another place due to some natural and human causes. In soil erosion, the topmost layer washes away to faraway lands, rivers and valleys. The degraded soil loses its quality and structure so it can be eroded more easily. Soil erosion occurs mainly on steep slopes with heavy rainfall in states like Assam, Manipur and Western Ghats. It also occurs in Maharashtra, Andhra Pradesh and Tamil Nadu. Soil compaction, loss of soil structure, low organic matter, poor internal drainage and soil acidity are some other problems lead to soil erosion.
Heavy Rainfall: India faces different climatic conditions all over year. In some places, where very heavy rainfall occurs, it carries away the soil nutrients and quality which leads to soil erosion especially on hilly areas or sloping terrains.
Wind: Soil erosion occurs mainly in less vegetative places, particularly in desert and semi-desert regions where strong breezes are very common. The small and dry particles of soil carried away by the wind and deposits somewhere else. This wind washing the topsoil is known as wind erosion which is a natural cause of soil erosion.
Soil Erodibility: Some soils are more prone to erosion than other and factors like organic matter content, structure, texture and permeability affects soil erodibility more.
Local Climate and Vegetation Loss: Local climate is one of the reasons to cause soil erosion due to sudden weather changes meaning some climates create perfect condition for soil erosion. Also, a good vegetative area acts as a shield between soil and drops of rain and breaks down the wind before it can reach the soil. So, the loss of vegetation is also a reason for soil erosion.
Mining: Mining is one of the major human causes of soil erosion. It removes the top layer of soil and can cause the loss of soil structure, and the compacted soil is more prone to erosion. It also leaves heavy metals and sediments near water bodies, reducing the water quality.
Deforestation: Deforestation is the leading cause of soil erosion as the cutting of trees leads to the detachment of the roots which causes the loss of soil structure. Trees shield the soil from heavy rainfall and maintain soil temperature, which reduces evaporation. Deforestation leads to excessive soil erosion, which increases runoff.
Shifting Agriculture: Another significant human cause of soil erosion is shifting agriculture. This practice involves temporary cultivation of land, followed by abandonment to allow it to revert to its natural state. However, this process leads to the loss of soil structure and nutrients, ultimately degrading the soil quality.
Soil erosion has a massive impact on agriculture as the most fertile soil loses its richness, thus decreasing soil productivity. Here are some significant impacts of soil erosion on agriculture:
Land Degradation: The two types of natural soil erosion, water and wind erosion are the major causes of land degradation. Around 75 billion tons soil is eroded yearly which is approximately 13-40 times as fast as the natural rate of erosion. Around 40% soil is degraded in the world.
Water Pollution: Water pollution is the serious effect of soil erosion. The eroded soil has pesticides, heavy metals, and fertilizers which mix with water ways which cause water pollution and destroy marine and freshwater habitats. It is also a threat to aquatic life forms.
Dust Pollution: Dust particles during wind erosion mix with toxic chemicals such as pesticides or petroleum fuels causes breathing problem when inhaled which is a serious problem.
Infrastructural Destruction: Soil erosion also affects dams, drainages, and embankments. It reduces their operational lifetime and efficiency.
Reduced Soil Fertility: Topsoil, the most fertile layer of soil, is crucial for agriculture. It's rich in organic matter, nutrients, and microorganisms that are essential for plant growth. However, soil erosion can strip away this vital layer, leading to a reduction in soil fertility, changes in soil structure, and pH imbalance, all of which can hinder crop growth.
Increased Pest Problem: During soil erosion, the reduced nutrient content weakens the soil, making it more vulnerable to pest infestations.
There are two types of preventive measures to control soil erosion. Let’s discuss each in detail.
Strip Cropping: Strip cropping involves the planting of erosion-permitting crops (jowar, bajra, maize) with erosion checking close- growing crops (grasses, pulses), which conserve soil moisture and reduce soil erosion by protecting the natural structure and organic matter in the unploughed areas.
Crop Rotation: Crop rotation helps to control soil erosion by making the soil undisturbed by alternating crops. It plays a crucial role in improving soil structure and allowing organic matter to build up for the upcoming crops.
Organic Manures: Using organic manure like cow dung and green manure in agricultural fields improves the overall moisture of the soil. It also increases the infiltration and permeability in the soil.
Stubble Mulching: Keep the stubble or mulch on the soil to control the wind access to the soil.
Contour Tillage: Tillage should be done at the right angle to the slopes. Through this, each furrow cuts off the flowing water, allowing it to soak into the soil.
Terracing: Terracing is practiced all over India to control soil erosion. By cultivating sloping lands into flat surfaces, it reduces the amount of water flowing across the soil surface, thus preventing soil erosion.
Water Harvesting: Water harvesting is another important measure to control soil erosion by collecting and storing rainwater through which the surface runoff is reduced.
National Mission for Sustainable Agriculture (NMSA): NMSA was launched by the Department of Agriculture and Farmer’s Welfare in 2014-15. The scheme aims at agricultural productivity, especially in rainfed areas, focusing on integrated farming, water use efficiency, soil health management and synergizing resource conservation.
Soil Health Card Scheme: The Soil Health Card was launched in 2015 with the initiative of improving farmers' soil quality and profitability and generating employment for rural youth. This card monitors the health of the soil and enables farmers to decide which crop to cultivate in their agricultural fields. This scheme has been merged with the Rashtriya Krishi Vikas Yojana (RKVY) cafeteria scheme as its one component under the name ‘Soil Health & Fertility’ from 2022-23.
Paramparagat Krishi Vikas Yojana (PKVY): As an extended component of the Soil Health Management (SHM) under the National Mission on Sustainable Agriculture (NMSA), the PKVY plays a crucial role in promoting and supporting organic farming. Its primary objective is to enhance soil health through the adoption of organic farming practices.
Soil erosion is the detachment of soil particles from one place to another place due to some natural and human causes.
Heavy rainfall, soil erodibility and deforestation are some causes of soil erosion in India.
We can reduce soil erosion by adopting some remedial strategies such as strip cropping, crop rotation, terracing and stubble mulching.
Wind erosion and water erosion are the two major types of natural soil erosion in India.
Deforestation and mining are the major human activities that leads to soil erosion.