155 Questions
What is the most important layer of the earth's crust for supporting trees, grasses, crops, and lifeforms?
Soil
What are the major factors affecting the formation of soil?
Relief, parent material, climate
Which component is NOT mentioned as part of the soil composition in the text?
Sunlight
How has soil evolved over thousands of years according to the text?
It has formed from weathering and gradation acting on parent rock material
Which agent(s) are responsible for producing a thin layer of soil from the parent rock material?
Weathering and gradation
What is derived from land-based crops that grow in the soil?
Food and clothing
What are the three layers that make up the soil profile?
Horizon A, Horizon B, Horizon C
Which layer of the soil profile contains organic materials necessary for plant growth?
Horizon A
What is the transition zone between Horizon A and Horizon C called?
Horizon B
Which of the following is NOT a type of soil classification as per the text?
Sandy and Silty
Which agency conducted comprehensive studies of soils in selected areas like the Damodar Valley?
Soil Survey of India
Which type of soil covers about 40% of the total area of India?
Alluvial soils
What do alluvial soils deposit away from flood plains represent?
Older alluvium
Which zone in the Upper and Middle Ganga plain is deposited annually by floods?
'Khadar'
Which soil type is generally rich in potash but poor in phosphorus?
'Alluvial soils'
Which type of soil retains moisture for a very long time, helping rain-fed crops sustain during dry seasons?
Black soil
What type of soil is known for developing wide cracks during the dry season due to its characteristics?
Black soil
In which part of India can we find black soils known as 'Regur Soil' or 'Black Cotton Soil'?
Deccan Plateau
Which soil type is more suitable for tree crops like cashewnut in states like Tamil Nadu, Andhra Pradesh, and Kerala?
Laterite soil
What is the main reason why laterite soils are not suitable for cultivation without external intervention?
Poor in organic matter, nitrogen, and phosphate
Which type of soil is sandy in structure, saline in nature, and ranges from red to brown in color due to its characteristics?
Arid soil
What causes the deep black to grey color range of alluvial soils in India?
Texture of materials
What makes red and yellow fine-grained soils fertile compared to coarse-grained soils in dry upland areas?
Presence of humus
Which remedial measure is suggested to eliminate finger gullies?
Terracing
How can the erosive velocity of water in bigger gullies be reduced?
Constructing check dams
What remedial measure is recommended to control the headward extension of gullies?
Terracing
In arid and semi-arid areas, what is suggested to protect cultivable lands from encroachment by sand dunes?
Developing shelter belts of trees
What technique is highlighted as the best for proper soil conservation in the text?
Land classification based on capability
'Regur Soil' is another name for which type of soil?
Black Soil
What is the main reason mentioned for the loss of top soil in India?
Water erosion
'Arable land in irrigated zones turning saline' is attributed to which factor?
Over irrigation
What organization prepared plans for soil conservation in different parts of India?
Central Soil Conservation Board
'Khadar' and 'Bhangar' are terms used to describe the difference in which type of soil?
Alluvial and Laterite soils respectively
What is one of the major causes of soil erosion mentioned in the text?
Deforestation for human activities
Which type of soil erosion is more significant in regions with heavy rainfall and steep slopes?
Gully erosion
What is the impact of sheet erosion on level lands?
Removal of topsoil after heavy shower
How does overirrigation contribute to soil degradation in India?
Causes salinity in arable land
What is the impact of chemical fertilizers without organic manures on soil fertility?
Hardens the soil
What happens to agricultural lands affected by gully erosion?
Fragmentation and unsuitability for cultivation
What is the term used for a region with a large number of deep gullies or ravines?
'Badland' topography
Why are forests important in preventing soil erosion?
To stabilize the soil with roots
What is the primary purpose of soil conservation as mentioned in the text?
To maintain soil fertility and prevent erosion
What is the main reason for the formation of 'Kankar' layers in the lower horizons of the soil?
Increasing calcium content downwards
Which type of soils are found in areas of heavy rainfall and high humidity?
Peaty soils
What is a characteristic feature of arid soils according to the text?
Contain little humus and organic matter
In which regions are saline soils more widespread according to the text?
Sunderban areas of West Bengal
What is the main reason for the presence of saline soils in arid and semi-arid regions?
Excessive irrigation with dry climatic conditions
What promotes the occurrence of saline soils in areas of seawater intrusions?
Dry climate and poor drainage
What is a characteristic feature of forest soils according to the text?
[Fertile valleys](top layer)
What is the main factor leading to the depleting soil resource base in India according to the text?
[Soil erosion](top layer)
'Soil degradation' can be defined as:
[Decline in soil fertility](top layer)
What are the major factors affecting the formation of soil?
Relief, parent material, climate, vegetation, and time
Which component is NOT mentioned as part of the soil composition in the text?
Gravel
What is the characteristic feature of arid soils according to the text?
Deficient in organic matter
How has soil evolved over thousands of years according to the text?
Under the influence of weathering and gradation from parent rock material
What is a term used to describe a region with a large number of deep gullies or ravines?
Badlands
Which type of soil is more suitable for tree crops like cashew nut in states like Tamil Nadu, Andhra Pradesh, and Kerala?
Alluvial soil
Which layer of the soil profile is composed of the loose parent material and serves as the first stage in the soil formation process?
Horizon C
Which institution made comprehensive studies of soils in selected areas like in the Damodar Valley?
National Bureau of Soil Survey
Which type of soil classification system has been adopted by the Indian Council of Agricultural Research to classify Indian soils?
United States Department of Agriculture (USDA) Soil Taxonomy
What percentage of the total area of India do Alluvial soils cover?
40%
What do Black soils in India exhibit that makes them suitable for certain crops?
High Calcium content
Which type of soil, found in arid regions, can be described as having high clay content leading to wide cracks during dry seasons?
Vertisols
'Khadar' and 'Bhangar' represent the differences between which types of soil in the Upper and Middle Ganga plain?
New alluvium and Older alluvium
What factor contributes to the formation of 'Kankar' layers in the lower horizons of the soil?
Increasing calcium content downwards
Why are Alluvial soils often rich in potash but poor in phosphorus?
Continuous floods wash away nutrients
Why are saline soils infertile and do not support vegetative growth?
Large proportion of sodium, potassium, and magnesium
Which type of soil is characterized by being transported and deposited by rivers and streams?
Alluvial soils
What characteristic feature is common in peaty soils?
Rich humus and organic content
Why do forest soils vary in structure and texture depending on the mountain environment?
Formation in different mountain environments
What makes Entisols different from Inceptisols in terms of soil classification?
Entisols form on flat terrains
What is the impact of soil degradation according to the text?
Decline in soil fertility
How does soil erosion disturb the balance between soil forming and erosional processes?
By altering the rate of removal of fine particles from the surface
What is a common characteristic feature of arid soils mentioned in the text?
Large deposits of salts
In what areas are peaty soils usually found?
Areas with heavy rainfall and high humidity
How are forest soils described in terms of their texture based on their formation location?
Coarse-grained in valley sides, loamy in upper slopes
What contributes to the depletion of the soil resource base in India as stated in the text?
Soil degradation due to erosion and misuse
Which remedial measure can be used to eliminate finger gullies?
Terracing
What is the most effective technique highlighted in the text for proper soil conservation?
Terracing
Why are shelter belts of trees and agro-forestry developed in arid and semi-arid areas?
To protect cultivable lands from sand dune encroachment
What is the main reason for the loss of topsoil in India?
Water erosion
In which zones is arable land turning saline due to over irrigation?
Irrigated zones
What method can reduce the erosive velocity of water in bigger gullies?
Check dams
What is the primary reason for the presence of saline soils in arid and semi-arid regions?
Over irrigation
'Regur Soil' is another name for which type of soil?
'Black Soil'
What characterizes black soils in terms of moisture retention during the dry season?
They are deep and impermeable, retaining moisture for a long time
Which soil type is known for developing wide cracks during the dry season?
Black Soil
Why are black soils not suitable for cultivation without external intervention?
They lack phosphorus, nitrogen, and organic matter
What is the primary reason for the reddish color of red soil?
Leaching of iron in rocks
In which areas are laterite soils commonly found according to the text?
Areas with high temperature and high rainfall
What characteristic feature makes red and yellow fine-grained soils fertile?
Presence of humus and phosphorus
Why are arid soils generally sandy and saline in nature?
Resulting from dry climate, high temperature, and evaporation
What is the main reason why laterite soils lack organic matter, nitrogen, phosphate, and calcium?
Intense leaching by tropical rains
What makes black soils develop wide cracks during the dry season?
Swelling and shrinking characteristics
Why are red and yellow coarse-grained soils generally poor in fertility compared to fine-grained ones?
Lack of nitrogen and phosphorus in coarse-grained soils
What type of erosion is more significant in arid and semi-arid regions?
Wind erosion
In which type of soil erosion is the soil removal not easily noticeable but harmful since it removes the finer and more fertile topsoil?
Sheet erosion
What is the term used for a region with a large number of deep gullies or ravines?
Badland topography
What is the primary cause of arable land in irrigated zones becoming saline?
Chemical fertilizers
Which factor contributes to overirrigated zones in India becoming saline and losing their fertility?
Lack of humus in the soil
How does deforestation contribute to soil erosion?
By loosening the soil structure
In which type of soil profile layer are organic materials necessary for plant growth found?
Horizon A
'Regur Soil' is another name for which type of soil found in India?
'Black Cotton Soil'
'Bhangar' and 'Khadar' are terms used to describe the difference in which type of soil?
'Alluvial Soil'
What role do human activities play in influencing the formation of soil?
They significantly influence soil formation
In the context of soil composition, what is humus primarily composed of?
Organic materials
Which factor has the least significant impact on the formation of soil as mentioned in the text?
Relief
What does the term 'Khadar' refer to in the context of soil types?
Alluvial soils
Which layer of the soil profile serves as the first stage in the soil formation process?
Parent material layer
What does the term 'Bhangar' refer to in relation to soil classification?
Red and yellow soils
What is the main reason for the formation of 'Kankar' layers in the lower horizons of the soil?
Increasing calcium content downwards
In which regions are 'Saline Soils' more likely to be found based on the text?
Western Gujarat and Sunderban areas of West Bengal
Which component is most likely to be lacking in Peaty Soils according to the text?
Calcium
What is the main cause for the development of forest soils with low humus content in snow-bound areas of the Himalayas?
Denudation
How do forest soils vary in texture based on their location within mountain environments?
Coarse-grained in valley sides
Why are arid soils in Western Rajasthan characterized as infertile?
Lack of nitrogen and calcium
Which soil type is more likely to be alkaline in nature based on the text?
'Peaty Soils'
What promotes the occurrence of saline soils in the deltas according to the text?
Seawater intrusions
How do 'Saline Soils' differ from 'Arid Soils' based on their composition?
'Saline Soils' have more salts due to dry climate and poor drainage.
'Peaty Soils' are found in regions with heavy rainfall. How does this heavy rainfall contribute to soil formation?
By accumulating large quantities of dead organic matter
What contributes to the reddish color of red soil in the eastern and southern part of the Deccan Plateau?
Presence of iron oxide in rocks
Why are black soils in India also known as 'Regur Soil'?
For their self-ploughing characteristics
Which element is found in excess in laterite soils but is insufficient in arid soils?
Potash
What characteristic feature of black soils allows them to sustain rain-fed crops during dry seasons?
High moisture retention
Why are red and yellow coarse-grained soils generally poor in fertility compared to fine-grained soils?
Low nitrogen content
What contributes to the high salt content in some arid soils where common salt is obtained by evaporating saline water?
Accelerated evaporation
Which soil type is not suitable for cultivation without external intervention due to its poor organic matter and nutrient content?
'Laterite' soil
What is the primary reason for black soils developing wide cracks during the dry season?
'Self-ploughing' characteristic
What contributes to the reddish color of red soil found along the piedmont zone of the Western Ghats?
Presence of iron diffusion in rocks
Which remedial measure is specifically recommended to control the headward extension of gullies?
Terracing
What is the main corrective action proposed to eliminate finger gullies?
Terracing
In arid and semi-arid regions, how can cultivable lands be safeguarded from encroachment by sand dunes?
Developing shelter belts of trees
Which institution conducted experiments to stabilize sand dunes in western Rajasthan?
Central Arid Zone Research Institute
What type of soil conservation technique is highlighted in the text as fragmental in nature?
Integrated land use planning
Which category of soil is found to be most saline in nature and is turning arable lands saline in irrigated zones according to the text?
Black Soil
What is the primary cause of arable land in irrigated zones turning saline as mentioned in the text?
Over irrigation
What type of erosion is more significant in arid and semi-arid regions?
Wind erosion
Which activity is NOT mentioned as a human cause of soil erosion in the text?
Terracing for farming
What is the term used for a region with a large number of deep gullies or ravines?
Badland topography
What is the main cause of soil degradation in the command areas of river valley projects?
Chemical fertilizers
What is the primary factor contributing to saline soils in arid and semi-arid regions?
Overirrigation
Why are chemical fertilizers, without organic manures, harmful to the soil in the long run?
They harden the soil and reduce its fertility
What is the negative impact of overirrigation on arable land in India?
Turns arable land saline
What is the primary purpose of soil conservation according to the text?
Maintain soil fertility, prevent erosion and exhaustion, improve degraded soils
In which regions are ravines most widespread according to the text?
Tamil Nadu and West Bengal
Which factor contributes significantly to the degradation of arable land in irrigated zones?
Improper use of chemical fertilizers
What is the primary reason for the different soil types found in India?
Variation in relief features, climatic realms, and vegetation types
Which agricultural practice has contributed to the depletion of the soil resource base in India?
Intensive irrigation methods
Why are 'Inceptisols' and 'Entisols' significant in soil classification according to the United States Department of Agriculture (USDA) taxonomy?
As they represent early stages of soil development
What distinguishes 'Ultisols' from 'Mollisols' in the classification of Indian soils?
Acidic nature and leaching of nutrients
What is a common feature of 'Aridisols' that sets them apart from other soil types?
Presence of wide cracks during dry seasons
How do 'Khadar' and 'Bhangar' differ in terms of alluvial soil composition?
'Khadar' represents new alluvium, and 'Bhangar' is older alluvium away from flood plains
What factor contributes to the formation of 'Laterite soils' known for their characteristic shortcomings?
'Kankar' layers developing in lower horizons of soil
What distinguishes 'Alluvial soils' regarding fertility levels compared to other soil types?
'Alluvial soils' are rich in potash but poor in phosphorus
What impact does industrial pollution have on forest soils as described in the text?
'Forest soils' lose their structure and texture due to pollution
Study Notes
Importance of Soil
- Soil is the most important layer of the earth's crust and a valuable resource.
- The bulk of our food and much of our clothing is derived from land-based crops that grow in the soil.
Soil Formation
- Soil is the mixture of rock debris and organic materials which develop on the earth's surface.
- The major factors affecting the formation of soil are relief, parent material, climate, vegetation, and other life-forms and time.
- Human activities also influence soil formation to a large extent.
Components of Soil
- Mineral particles, humus, water, and air are the components of soil.
- The actual amount of each of these components depends upon the type of soil.
Soil Profile
- A soil profile consists of three layers: Horizon A, Horizon B, and Horizon C.
- Horizon A is the topmost zone where organic materials have got incorporated with the mineral matter, nutrients, and water.
- Horizon B is a transition zone between Horizon A and Horizon C, and contains matter derived from below as well as from above.
- Horizon C is composed of the loose parent material.
Classification of Soil
- Soil classification is an effort to understand the importance of soil.
- Indian soils have been classified into: Inceptisols, Entisols, Alfisols, Vertisols, Aridisols, Ultisols, Mollisols, and Others.
Types of Soil
- Alluvial soils: widespread in the northern plains and the river valleys, rich in potash but poor in phosphorous.
- Black soils: found in the Deccan Plateau, clayey, deep, and impermeable, retain moisture for a long time.
- Red and Yellow soils: develop on crystalline igneous rocks, poor in nitrogen, phosphorous, and humus.
- Laterite soils: develop in areas with high temperature and high rainfall, poor in organic matter, nitrogen, phosphate, and calcium.
- Arid soils: sandy in structure, saline in nature, lack moisture and humus.
- Saline soils: infertile, contain a larger proportion of sodium, potassium, and magnesium, and do not support vegetative growth.
- Peaty soils: found in areas of heavy rainfall and high humidity, rich in humus and organic matter.
- Forest soils: formed in the forest areas, vary in structure and texture, and are fertile in the lower valleys.
Soil Degradation
- Soil degradation is the decline in soil fertility, occurs due to erosion and misuse.
- The degree of soil degradation varies from place to place according to the topography, wind velocity, and amount of rainfall.
Soil Erosion
- Soil erosion is the destruction of the soil cover, occurs due to wind and water erosion.
- Water erosion is more serious and occurs extensively in different parts of India, mainly in the form of sheet and gully erosion.
- Deforestation is one of the major causes of soil erosion.
- Over-irrigation, chemical fertilisers, and lack of humus are also harmful to the soil.
Soil Conservation
- Soil conservation is a methodology to maintain soil fertility, prevent soil erosion and exhaustion, and improve the degraded condition of the soil.
- Soil erosion can be prevented by humans, and it is essential to initiate immediate steps to reclaim and conserve soils.
- Soil conservation measures include regulating and controlling over-grazing and shifting cultivation, and educating villagers about the consequences of soil erosion.### Soil Conservation and Classification
- Soil erosion can be reduced through measures such as contour bunding, contour terracing, regulated forestry, controlled grazing, cover cropping, mixed farming, and crop rotation.
- Efforts should be made to prevent gully erosion and control their formation, such as by constructing check dams and planting cover vegetation.
Soil Formation and Components
- Soil is a mixture of rock debris and organic materials that develop on the earth's surface.
- The major factors affecting soil formation are relief, parent material, climate, vegetation, and time, as well as human activities.
- Soil components include mineral particles, humus, water, and air, with varying amounts depending on the type of soil.
Soil Profile and Horizons
- A soil profile consists of three layers: Horizon A (topmost zone), Horizon B (transition zone), and Horizon C (loose parent material).
- Each horizon has distinct characteristics, with Horizon A containing organic materials and nutrients, Horizon B being a transition zone, and Horizon C being the parent material.
Soil Classification in India
- Indian soils have been classified into eight categories: Inceptisols, Entisols, Alfisols, Vertisols, Aridisols, Ultisols, Mollisols, and others.
- Soils have also been classified based on their genesis, color, composition, and location, including Alluvial soils, Black soils, Red and Yellow soils, Laterite soils, Arid soils, Saline soils, Peaty soils, and Forest soils.
Types of Soils in India
- Alluvial soils: widespread in northern plains and river valleys, rich in potash but poor in phosphorus.
- Black soils (Regur soils): found in Deccan Plateau, clayey, deep, and impermeable, with high iron oxide and alumina content.
- Red and Yellow soils: found in eastern and southern parts of Deccan Plateau, developed on crystalline igneous rocks, poor in nitrogen and phosphorus.
- Laterite soils: developed in areas with high temperature and rainfall, poor in organic matter and nutrients, but rich in iron oxide and potash.
- Arid soils: found in western Rajasthan, sandy in structure, saline in nature, with low humus and organic matter content.
Soil Degradation and Erosion
-
Soil degradation: decline in soil fertility, resulting in reduced nutritional status and depth of soil due to erosion and misuse.
-
Soil erosion: destruction of soil cover, caused by an imbalance between soil formation and erosional processes, leading to removal of fine particles from the surface.### Soil Erosion
-
Human activities, such as deforestation, overgrazing, and cultivation, are significant contributors to soil erosion.
-
Soil erosion is a serious problem in India, with about 8,000 hectares of land lost to ravines every year.
-
Gully erosion is common in regions with steep slopes, and can be prevented by terracing, contour bunding, and regulated forestry.
Types of Soil Erosion
- Wind erosion: significant in arid and semi-arid regions.
- Water erosion: more serious and widespread in India, occurring in the form of sheet and gully erosion.
Soil Conservation
- Soil conservation is essential to prevent soil erosion and maintain soil fertility.
- Measures to conserve soil include: • Contour bunding and contour terracing • Regulated forestry and controlled grazing • Cover cropping, mixed farming, and crop rotation • Preventing gully erosion and controlling headward extension of gullies • Protecting cultivable lands from encroachment by sand dunes
Soil Formation
- Soil is formed through the interaction of relief, parent material, climate, vegetation, and other life-forms, and time.
- Human activities also influence soil formation.
- Soil components include mineral particles, humus, water, and air.
Soil Profile
- A soil profile consists of three horizons: A, B, and C.
- Horizon A: topmost zone with organic materials, nutrients, and water.
- Horizon B: transition zone between horizons A and C, with some organic matter and weathered mineral matter.
- Horizon C: composed of loose parent material, the first stage in soil formation.
Soil Classification
- Indian soils are classified into eight categories according to the USDA Soil Taxonomy.
- These categories are: • Inceptisols • Entisols • Alfisols • Vertisols • Aridisols • Ultisols • Mollisols • Others
Types of Soil
- Alluvial soils: widespread in the northern plains and river valleys, rich in potash but poor in phosphorous.
- Black soils: cover the Deccan Plateau, clayey, deep, and impermeable, with high lime, iron, magnesia, and alumina content.
- Red and Yellow soils: develop on crystalline igneous rocks in areas of low rainfall, with high iron oxide content.
- Laterite soils: develop in high-temperature and high-rainfall areas, with high iron oxide and aluminium content, poor in organic matter, nitrogen, phosphate, and calcium.
- Arid soils: range from red to brown in color, sandy in structure, and saline in nature, with low moisture and humus content.
Learn about the soil characteristics in western Rajasthan, including the presence of 'kankar' layers, limited water infiltration, and low organic matter. Explore how these conditions affect plant growth in arid regions.
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