Definitions [1]
Definition: Soil Erosion
The loss of soil or disturbance of the soil structure is called soil erosion.
Key Points
Key Points: Introduction to Soil in India
- Soil is a thin layer of weathered rock and humus that supports life.
- Soil forms slowly due to weathering, water, wind, and organic processes.
- Humus increases soil fertility.
- Soil erosion is caused by deforestation and overgrazing.
- Soils are residual or transported (e.g., alluvial soil).
Key Points: Soil Formation and Factors Affecting It
- Soil formation (pedogenesis) occurs due to disintegration and denudation of rocks.
- Parent rock decides the type of soil, e.g. black soil from basalt rock.
- Vegetation adds humus, increases fertility, and reduces soil erosion.
- Climate controls the rate and type of weathering and decomposition.
- Soils are of two types: Residual (zonal) soils formed in situ and Transported (azonal) soils like alluvial soil.
Key Points: Types of Soil > Alluvial Soil
- Alluvial soil is formed by river deposits (alluvium) and is also called riverine soil.
- It covers about 40% of India, mainly in the Northern Plains, coastal plains, and river deltas.
- Alluvial soil is of two types: Bhangar (old, less fertile) and Khadar (new, very fertile).
- It is a mixture of sand, silt, and clay (loam) and is rich in minerals like potash and lime.
- It is suitable for crops like rice, wheat, sugarcane, cotton, jute, and oilseeds.
Key Points: Types of Soil > Black Soil
- Black soil is also called Black Cotton soil or Regur soil and is formed from weathered volcanic (basalt) rocks.
- It is an in-situ (residual) soil mainly found in the Deccan Plateau (Maharashtra, Gujarat, MP, Karnataka, Telangana).
- This soil is fine-grained, clayey, and highly moisture-retentive, making it suitable for dry farming.
- In dry season it develops deep cracks and is called self-ploughing soil, which helps maintain fertility.
- It is rich in iron, lime, and potash but poor in nitrogen and humus, and is ideal for cotton, wheat, jowar, and oilseeds.
Key Points: Types of Soil > Red Soil
- Red soil is formed by the weathering of ancient crystalline and metamorphic rocks and gets its red colour from iron oxide.
- It is the second largest soil group in India, mainly found in the Peninsular Plateau (Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Odisha, Chhattisgarh, and parts of North-East India).
- Red soil is porous, loose, and generally shallow, with low moisture-retention capacity.
- It is poor in nitrogen, phosphorus, humus, and lime, but rich in potash, and responds well to irrigation and fertilizers.
- It is suitable for dry farming and crops like rice, ragi, pulses, groundnut, tobacco, potatoes, and oilseeds.
Key Points: Types of Soil > Laterite Soils
- Laterite soil is formed due to heavy rainfall and high temperature with alternate wet and dry periods, causing leaching (desilication).
- It is a residual soil, red in colour due to iron oxide, and is acidic in nature.
- Laterite soil is poor in nutrients like nitrogen, lime, humus, and magnesium, and has low moisture-retention capacity.
- It is mainly found on the Western and Eastern Ghats and in parts of Kerala, Karnataka, Odisha, Maharashtra, Andhra Pradesh, and Tamil Nadu.
- It is suitable for plantation crops like tea, coffee, rubber, cashewnut, and is also used as building material when hardened.
Key Points: Soil Erosion
- Soil erosion is the removal of the top fertile layer of soil by water, wind, and human activities.
- Soil erosion by water includes sheet erosion, rill erosion, gully erosion, leaching, sea erosion, and stream-bank erosion.
- Wind erosion occurs in dry and semi-arid regions where loose soil is carried away by strong winds, reducing soil fertility.
- Human activities such as deforestation, overgrazing, improper farming, and shifting cultivation greatly increase soil erosion.
- Soil erosion reduces agricultural productivity, leads to land degradation, and creates a cycle of poverty.
Key Points: Causes of Soil Erosion
- High population pressure on land leads to deforestation and overuse of land, which is a major cause of soil erosion in India.
- Nature of rainfall in India—heavy monsoon rains and frequent droughts—causes floods and washing away of fertile topsoil.
- Overgrazing by cattle removes vegetation cover, leaving soil exposed to wind and water erosion, especially in Rajasthan.
- Bad farming practices like lack of terracing, contour ploughing, crop rotation, and improper use of manure increase soil erosion.
- Steep slopes and deforestation in hilly regions such as the Shiwaliks, Himalayas, and parts of South India make these areas highly prone to soil erosion.
Key Points: Prevention of Soil Erosion
- Terrace farming and contour ploughing reduce soil erosion on hilly slopes by slowing down running water.
- Afforestation and shelter belts protect soil by holding soil particles, reducing wind speed, and increasing water percolation.
- Strip cropping and crop rotation help prevent erosion by holding soil with crop roots and maintaining soil fertility.
- Dams, embankments, and plugging of gullies control soil erosion caused by rivers and surface runoff.
- Soil conservation is vital because soil forms very slowly, supports food production, biodiversity, and climate balance, and its loss leads to droughts, floods, and reduced fertility.
Key Points: Soil Conservation
- Soil conservation means protecting soil from erosion and maintaining its fertility.
- Soil erosion causes loss of fertile topsoil, leading to reduced agricultural productivity.
- Soil conservation helps maintain soil moisture and raise the groundwater level.
- It prevents silting of rivers, floods, droughts, and landslides, especially in hilly areas.
- Soil conservation is essential because soil forms very slowly but can be destroyed quickly, and it supports plants, animals, and human life.
Key Points: Soil Conservation Schemes Initiated by the Government
- The Government of India has started soil conservation schemes to reduce soil erosion and improve agricultural productivity.
- Ravine reclamation programmes help control and reclaim ravine areas in Madhya Pradesh, Uttar Pradesh, and Rajasthan through bunding and plantation.
- Shifting cultivation is controlled by resettling tribal people, increasing forest cover, and providing employment and food security schemes.
- Rainwater harvesting reduces surface runoff, prevents soil erosion, raises the groundwater table, and supports multiple cropping.
- Biofertilizers and the Integrated Watershed Management Programme (IWMP) improve soil fertility, conserve water and vegetation, and provide sustainable livelihoods.
Key Points: Alluvial Soil VS Black Soil VS Red Soil VS Laterite Soil
| Soil Type | Formation | Main Areas | Key Characteristics | Major Crops |
|---|---|---|---|---|
| Alluvial Soil | River deposits | Northern Plains, coastal & delta regions | Loamy, fertile, rich in potash & lime | Rice, wheat, sugarcane, cotton, jute |
| Black Soil | Weathering of lava rocks | Deccan Plateau | Clayey, moisture-retentive | Cotton, cereals, sugarcane |
| Red Soil | Weathering of crystalline rocks | Peninsular Plateau | Red due to iron, poor in nitrogen | Rice, ragi, groundnut, vegetables |
| Laterite Soil | Leaching due to heavy rainfall | Western & Eastern Ghats | Coarse, porous, acidic | Tea, coffee, rubber, tapioca |
| Soils in India | Vary by origin & climate | Different regions | Differ in fertility & texture | Decide crop patterns |
Important Questions [18]
- Give one difference between the following: Transported soil and residual soil.
- Name the soil: That varies in texture.
- Which is the most widespread soil of India?
- Give one difference between the following: Alluvial soil of Uttarakhand and alluvial soil of West Bengal.
- Why is Black soil found suitable for the production of cotton? (Any two points)
- Mention two characteristics of black soil.
- Name the soil: That is suitable for dry farming.
- With reference to Red Soils in India, answer the following question: Name two states where it is found.
- With reference to Laterite soil, answer the question that follows: How is Laterite Soil formed?
- With reference to Laterite soil, answer the question that follow: Name one region where Laterite soil is found.
- With reference to Laterite soil, answer the question that follow: How can Laterite soil be made productive?
- Name the soil: That is found on the summits of Eastern and Western Ghats.
- How has the rising population of India resulted in the loss of forest cover? (Any one point)
- Mention any two causes of soil erosion in India.
- Give a geographical reason for the following: Terrace farming is an ideal soil conservation method for hilly areas.
- Which of the following helps in soil conservation?
- Mention a soil conservation method suitable for hilly area.
- Name two soil conservation methods that may be practised in arid (dry).
Concepts [12]
- Introduction to Soil in India
- Soil Formation and Factors Affecting It
- Types of Soil > Alluvial Soil
- Types of Soil > Black Soil
- Types of Soil > Red Soil
- Types of Soil > Laterite Soils
- Soil Erosion
- Causes of Soil Erosion
- Prevention of Soil Erosion
- Soil Conservation
- Soil Conservation Schemes Initiated by the Government
- Alluvial Soil VS Black Soil VS Red Soil VS Laterite Soil
