Worksheet Solutions: Soils | Geography for Grade 11 PDF Download

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Q1: Soil is the mixture of __________ and __________ which develop on the earth's surface.
Ans: rock debris and organic materials
Soil is composed of broken-down rock debris and organic materials like decaying plant and animal matter.

Q2: 'Horizon A' in the soil profile is the topmost zone, rich in __________ and necessary for plant growth.
Ans: organic materials
Horizon A, also known as the topsoil, is essential for plant growth due to its high organic material content.

Q3: Alluvial soils cover about __________ percent of the total area of India.
Ans: 40 percent
Alluvial soils are widespread in India and make up approximately 40 percent of the country's land area.

Q4: Black soils are also known as __________ soil.
Ans: Regur Soil
Black soils are often referred to as Regur Soil due to their unique properties.

Q5: Red soil develops on __________ rocks in areas of low rainfall.
Ans: crystalline igneous
Red soil is formed from weathered crystalline igneous rocks and is common in regions with low rainfall.

Q6: Laterite soils are the result of intense leaching due to __________.
Ans: tropical rains
Laterite soils form in areas with high rainfall and intense leaching, where lime and silica are leached away, leaving behind iron oxide and aluminum compounds.

Q7: Arid soils are characterized by their sandy structure and __________ nature.
Ans: sandy, saline
Arid soils are sandy in structure and may have high saline content, making them unsuitable for most crops.

Q8: Saline soils contain a larger proportion of __________, __________, and __________.
Ans: sodium, potassium, and magnesium
Saline soils are characterized by their high content of sodium, potassium, and magnesium, making them infertile.

Q9: Peaty soils are found in areas of heavy __________ and high humidity.
Ans: rainfall
Peaty soils form in regions with abundant rainfall and humidity, leading to the accumulation of organic matter.

Q10: Soil degradation is defined as the decline in soil __________ and __________.
Ans: fertility and depth
Soil degradation refers to the deterioration of soil quality, including a decrease in fertility and a reduction in soil depth, primarily caused by factors like erosion and improper land use.

Assertion and Reason Based

Q1: Assertion: Alluvial soils in India are rich in phosphorous.
Reason: These soils are formed by the deposition of weathered material carried by rivers.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
(c) Assertion is true, but Reason is false.
(d) Assertion is false, but Reason is true.
Ans: (b)
Alluvial soils in India are generally rich in phosphorus due to their origin from weathered materials, but this isn't the sole reason. The assertion is true, and the reason is also true but not a direct explanation of the assertion.

Q2: Assertion: Black soils are highly suitable for tree crops like cashewnut.
Reason: Black soils have a high content of organic matter.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
(c) Assertion is true, but Reason is false.
(d) Assertion is false, but Reason is true.
Ans: (b)
Black soils are indeed suitable for tree crops like cashewnut due to their moisture retention properties, but the reason provided, high organic matter content, is not the primary factor. The assertion is true, and the reason is also true but not the direct cause.

Q3: Assertion: Saline soils are fertile and support extensive vegetative growth.
Reason: These soils contain a large proportion of sodium, potassium, and magnesium.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
(c) Assertion is true, but Reason is false.
(d) Assertion is false, but Reason is true.
Ans: (d)
The assertion is false because saline soils are not fertile and do not support vegetative growth. The reason is true; these soils do contain high levels of sodium, potassium, and magnesium, which are detrimental to plant growth.

Q4: Assertion: Peaty soils have a low organic content.
Reason: These soils are found in areas of high humidity and heavy rainfall.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
(c) Assertion is true, but Reason is false.
(d) Assertion is false, but Reason is true.
Ans: (c)
The assertion is true because peaty soils actually have a high organic content, not low. The reason is false because peaty soils do form in regions with high humidity and rainfall, contributing to their rich organic matter.

Q5: Assertion: Soil conservation is mainly needed in areas with flat terrain.
Reason: Soil erosion is not a significant issue in hilly regions.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
(c) Assertion is true, but Reason is false.
(d) Assertion is false, but Reason is true.
Ans: (d)
The assertion is false because soil conservation is needed in various terrains, not just flat areas. The reason is true as soil erosion is indeed a significant issue in hilly regions as well.

Very Short Answer Type Questions

Q1: List the major factors affecting soil formation.
Ans: The major factors affecting soil formation include parent material, climate, organisms, topography, and time.

Q2: Define 'Horizon A' in the soil profile.
Ans: 'Horizon A' is the topmost layer of the soil profile, also known as the topsoil. It is rich in organic matter and minerals, making it suitable for plant growth.

Q3: What are Khadar and Bhangar soils?
Ans: Khadar soils are newer alluvial soils found in the floodplains of rivers, rich in organic matter and nutrients. Bhangar soils, on the other hand, are older alluvial soils found on the terraces above the floodplains, relatively less fertile than Khadar soils.

Q4: Explain why black soil retains moisture for a long time.
Ans: Black soil, also known as regur soil or black cotton soil, has a high clay content. Clay particles have a high water-holding capacity, allowing black soil to retain moisture for a long time.

Q5: What causes the reddish color in red soil?
Ans: The reddish color in red soil is primarily caused by the presence of iron oxide. Iron oxide imparts the red hue to the soil.

Q6: Why are laterite soils not suitable for cultivation without amendments?
Ans: Laterite soils are highly leached and lack essential nutrients for plant growth. They are acidic and have poor water-holding capacity, making them unsuitable for cultivation without amendments.

Q7: Mention the regions in India where arid soils are commonly found.
Ans: Arid soils are commonly found in regions such as Western Rajasthan, parts of Gujarat, and the southern part of Punjab.

Q8: What characterizes saline soils, and where are they found in India?
Ans: Saline soils are characterized by a high salt content, making them unsuitable for most crops. They are found in coastal areas, such as the Rann of Kutch in Gujarat and the coastal regions of Tamil Nadu.

Q9: Describe the characteristics of peaty soils.
Ans: Peaty soils are characterized by a high organic matter content due to the accumulation of partially decomposed plant material. They have a dark color, are acidic, and have a high water-holding capacity.

Q10: What is the primary cause of soil erosion in hilly regions?
Ans: The primary cause of soil erosion in hilly regions is the steep slope and heavy rainfall, which leads to the rapid runoff of water, carrying away the topsoil.

Short Answer Type Questions

Q1: Discuss the characteristics and distribution of black soil in India.
Ans: Black soil, also known as regur soil or black cotton soil, is a type of soil that is rich in clay and organic matter. It is highly fertile and can retain moisture well, making it suitable for agriculture. The black color is due to the presence of iron and aluminum oxides.
Black soil is mainly found in the Deccan Plateau region of India, covering states such as Maharashtra, Gujarat, Karnataka, and Madhya Pradesh. The distribution is prominent in areas with a semi-arid climate. The soil is formed from the weathering of basaltic rocks, which are rich in iron and magnesium.
The characteristics of black soil include high fertility, good moisture retention, and the ability to swell and shrink with changes in moisture content. It has a high cation exchange capacity, which allows it to hold and exchange nutrients effectively. However, black soil can become sticky and hard when dry, making it difficult to cultivate.

Q2: Explain the formation and characteristics of red and yellow soil.
Ans: Red and yellow soils are formed through the process of leaching, which involves the removal of minerals and nutrients from the soil as water percolates through it. This leaching process leads to the accumulation of iron and aluminum oxides, giving the soil its characteristic colors.
Red soil is formed in areas with high rainfall and well-drained conditions. It is typically found in the eastern and southern parts of India, including states like Odisha, Tamil Nadu, and Karnataka. Red soil is sandy and loamy in texture, and it lacks fertility due to leaching.
Yellow soil, on the other hand, is found in areas with less rainfall and better drainage. It is common in parts of Central India, Rajasthan, and parts of the Deccan Plateau. Yellow soil is also sandy and loamy but has a higher fertility compared to red soil. It contains a moderate amount of nutrients and organic matter.

Q3: Describe the factors responsible for the development of laterite soils.
Ans: Laterite soils are formed in areas with high temperatures and heavy rainfall, typically in tropical regions.
The development of laterite soils is influenced by several factors:

• Climate: High temperatures and heavy rainfall promote the leaching process, leading to the formation of laterite soils.
• Parent Material: Laterite soils are derived from rocks rich in iron and aluminum, such as basalt and granite. The weathering of these rocks contributes to the formation of laterite soils.
• Time: The formation of laterite soils is a slow process that takes thousands of years. Over time, the leaching process and weathering of rocks contribute to the development of laterite soils.

Laterite soils are characterized by their reddish-brown color, which is due to the presence of iron oxides. They are rich in iron and aluminum but are generally poor in nutrients and organic matter. Laterite soils have a low water-holding capacity and can become hard when dry.

Q4: Discuss the properties and challenges associated with arid soils in India.
Ans: Arid soils, also known as desert soils, are found in the arid and semi-arid regions of India, such as Rajasthan and parts of Gujarat. These soils are formed under arid climatic conditions and are characterized by their sandy texture and low organic matter content.
The properties of arid soils include:

• Coarse Texture: Arid soils are sandy in nature with a low clay content. This results in poor water-holding capacity and rapid drainage.
• Low Organic Matter: Due to the scarcity of vegetation and limited organic inputs, arid soils have a low organic matter content. This affects their fertility and nutrient-holding capacity.
• High pH: Arid soils are often alkaline in nature, with a high pH value. This can restrict the availability of certain nutrients to plants.

Challenges associated with arid soils include water scarcity, low fertility, and soil erosion. The lack of water limits agricultural productivity, and the low nutrient content requires additional inputs for cultivation. Soil erosion is a common issue in arid regions due to the loose texture of the soil and the lack of vegetation cover.

Q5: Explain the characteristics and distribution of saline soils in the country.
Ans: Saline soils, also known as salt-affected soils, are characterized by their high salt content. These soils are found in coastal regions where seawater intrusion occurs, as well as in arid and semi-arid regions with poor drainage.
The characteristics of saline soils include:

• High Salt Content: Saline soils have a high concentration of salts, such as sodium chloride, calcium sulfate, and magnesium sulfate. These salts can negatively affect plant growth.
• Poor Drainage: Saline soils often have poor drainage, leading to waterlogging and the accumulation of salts in the soil profile.
• Low Fertility: The presence of salts inhibits nutrient uptake by plants, resulting in low fertility.

Saline soils are distributed in coastal areas of Gujarat, Tamil Nadu, and West Bengal, as well as in parts of Haryana, Punjab, and Rajasthan. They pose a significant challenge for agriculture as most crops are unable to tolerate high salt concentrations. However, certain salt-tolerant crops like mangroves and halophytes can thrive in saline soil conditions.

Q6: Discuss the unique characteristics of peaty soils and their geographical distribution in India.
Ans: Peaty soils, also known as peat soils or organic soils, are characterized by their high organic matter content. They are formed in waterlogged areas with poor drainage, where plant residues accumulate and undergo partial decomposition.
The unique characteristics of peaty soils include:

• High Organic Matter: Peaty soils contain a high percentage of organic matter, which can range from partially decomposed plant material to fully decomposed organic matter known as peat.
• Acidic pH: Peaty soils are typically acidic due to the accumulation of organic acids during the decomposition process.
• High Water-Holding Capacity: The high organic matter content in peaty soils allows them to hold a significant amount of water, resulting in waterlogged conditions.

Peaty soils are mainly found in the coastal areas of Kerala, Tamil Nadu, and the Sunderban delta in West Bengal. These areas have a high rainfall and are characterized by marshy and swampy conditions. Peaty soils are suitable for the cultivation of crops like paddy rice and certain horticultural crops. However, they require proper drainage and management to prevent waterlogging and maintain fertility.

Q7: What are forest soils, and how do their properties vary in different regions of India?
Ans: Forest soils, as the name suggests, are soils that are found in forested areas. They are characterized by their high organic matter content and fertility due to the continuous input of organic material from fallen leaves, branches, and decaying vegetation.
The properties of forest soils vary in different regions of India based on factors such as climate, vegetation type, and parent material.
In general, forest soils exhibit the following characteristics:

• High Organic Matter: Forest soils have a high organic matter content, which contributes to their fertility and nutrient-holding capacity.
• Acidic pH: Due to the decomposition of organic matter, forest soils are often acidic in nature.
• Good Water-Holding Capacity: The presence of organic matter in forest soils allows them to retain moisture well, promoting plant growth.

In the Himalayan region, forest soils are characterized by a deep layer of organic matter and high fertility. In the Western Ghats and northeastern states, forest soils are rich in iron and aluminum oxides. In the coastal regions, forest soils are sandy in texture and have a lower organic matter content.

Q8: Define soil degradation and discuss its causes and consequences.
Ans: Soil degradation refers to the decline in the quality and productivity of soil due to various factors. It is a result of both natural processes and human activities.
The causes of soil degradation include:

• Erosion: Soil erosion, both water and wind erosion, removes the topsoil layer, which is rich in nutrients and organic matter.
• Deforestation: Clearing of forests reduces the protective cover of vegetation, leading to increased erosion and loss of soil fertility.
• Overgrazing: Excessive grazing by livestock can damage vegetation cover and compact the soil, making it more prone to erosion.
• Chemical Pollution: The excessive use of chemical fertilizers, pesticides, and industrial pollutants can degrade soil quality and contaminate groundwater.

The consequences of soil degradation are significant:

• Reduced Agricultural Productivity: Degraded soil has lower fertility, nutrient content, and water-holding capacity, leading to decreased crop yields.
• Increased Soil Erosion: Soil degradation exacerbates erosion, resulting in the loss of topsoil and valuable nutrients.
• Desertification: Degraded soil can contribute to the expansion of desert areas, making land unsuitable for agriculture or any productive use.
• Water Pollution: Soil degradation can lead to the contamination of water bodies through the leaching of pollutants and sedimentation.

Addressing soil degradation requires sustainable land management practices, such as soil conservation, afforestation, crop rotation, and judicious use of inputs. It is crucial to prevent further degradation and restore degraded soils to ensure long-term agricultural productivity and environmental sustainability.

Long Answer Type Questions

Q1: Explain the concept of soil conservation and its significance in agriculture. Provide examples of soil conservation methods.
Ans: Soil conservation refers to the practice of preventing soil erosion and degradation to maintain the quality and fertility of the soil. It is of utmost significance in agriculture as healthy soil is essential for successful crop growth and sustainable food production.
There are several soil conservation methods that can be implemented:

• Contour plowing: This method involves plowing along the contour lines of the land, which helps to slow down the flow of water and prevent soil erosion.
• Terracing: Terraces are constructed on hilly or sloping lands to create flat surfaces. This technique helps to control water runoff and reduces soil erosion.
• Crop rotation: Crop rotation involves growing different crops in a specific sequence on the same piece of land. This practice helps to maintain soil fertility, control pests and diseases, and prevent soil nutrient depletion.
• Cover cropping: Cover crops, such as legumes or grasses, are planted in between growing seasons to protect the soil from erosion, improve soil structure, and add organic matter.
• Conservation tillage: This method involves reducing the intensity of tillage or completely eliminating it. By minimizing soil disturbance, conservation tillage helps to retain moisture, reduce erosion, and improve soil health.
• Windbreaks: Planting rows of trees or shrubs along the edges of fields helps to create windbreaks, reducing wind erosion and protecting the soil.

These soil conservation methods aid in preserving the integrity of the soil, preventing erosion, maintaining soil fertility, and promoting sustainable agriculture practices.

Q2: Discuss the causes and consequences of soil erosion in India, highlighting its impact on agriculture and the environment.
Ans: Soil erosion in India is primarily caused by various factors, including:

• Water erosion: Heavy rainfall, improper land management, and inadequate drainage systems contribute to water erosion in India. This type of erosion is particularly prevalent in hilly areas and leads to the loss of topsoil and valuable nutrients.
• Wind erosion: Dry and arid regions in India experience wind erosion, which occurs when strong winds pick up and carry away loose soil particles. It is common in areas with little vegetation cover.
• Unsustainable agricultural practices: Intensive farming techniques, excessive tillage, improper irrigation, and the use of chemical fertilizers and pesticides can accelerate soil erosion. These practices degrade the soil structure and reduce its ability to retain water.

The consequences of soil erosion in India are significant:

• Reduced agricultural productivity: Soil erosion depletes the topsoil, which is rich in nutrients necessary for crop growth. This leads to decreased agricultural productivity and lower crop yields.
• Water pollution: Eroded soil, along with chemical residues from fertilizers and pesticides, can contaminate water bodies. This pollution adversely affects water quality and aquatic ecosystems.
• Increased flood risk: Soil erosion reduces the capacity of the soil to absorb and retain water, resulting in increased surface runoff. This can contribute to flash floods and increased flood risk in vulnerable areas.
• Loss of biodiversity: Soil erosion affects the habitat and ecosystem of various organisms, leading to a decline in biodiversity and disrupting ecological balance.

To mitigate the impact of soil erosion, sustainable land management practices, afforestation, contour plowing, and proper water management systems need to be implemented. These measures help in preserving soil fertility, protecting the environment, and ensuring long-term agricultural sustainability.

Q3: Compare and contrast the characteristics of alluvial soils, black soils, and red soils in terms of their formation, properties, and agricultural significance.
Ans: Alluvial soils, black soils, and red soils are three distinct types of soils found in India.
Here is a comparison of their characteristics:
1. Alluvial soils:

• Formation: Alluvial soils are formed by the deposition of sediments carried by rivers and streams. They are typically found in the floodplains and deltas of major rivers like the Ganges and Brahmaputra.
• Properties: Alluvial soils are fertile, well-drained, and rich in organic matter. They have a fine texture and good moisture-retaining capacity.
• Agricultural significance: Alluvial soils are highly suitable for agriculture and support the cultivation of various crops, including rice, wheat, sugarcane, and vegetables.

2. Black soils (Regur soils):

• Formation: Black soils are formed from the weathering of basaltic lava rocks. They are predominantly found in the Deccan Plateau region of India.
• Properties: Black soils are clayey and have a high moisture-holding capacity. They are known for their deep black color due to the presence of iron and aluminum oxides.
• Agricultural significance: Black soils are highly fertile and retain moisture well, making them ideal for growing cotton, cereals, oilseeds, and tobacco.

3. Red soils:

• Formation: Red soils are formed from the weathering of ancient crystalline rocks. They are commonly found in regions with moderate rainfall and well-drained slopes.
• Properties: Red soils are sandy or loamy in texture and have a reddish color due to the presence of iron oxide. They are less fertile compared to alluvial and black soils.
• Agricultural significance: Red soils are suitable for growing crops like millets, pulses, oilseeds, and fruits. However, they require proper irrigation and nutrient management to improve their fertility.

While alluvial soils are fertile and well-suited for a wide range of crops, black soils are known for their high moisture retention capacity, and red soils require proper management to enhance their fertility. Understanding these soil characteristics helps farmers determine the most suitable crops and agricultural practices for maximizing productivity.

Q4: Analyze the challenges associated with soil degradation in India and propose solutions to mitigate this issue, emphasizing the role of sustainable agricultural practices and government initiatives.
Ans: Soil degradation is a significant challenge in India, and it is crucial to address this issue to ensure sustainable agricultural practices.
Some of the key challenges associated with soil degradation in India are:

• Erosion: Water and wind erosion result in the loss of topsoil, which is rich in nutrients. Improper land management practices and natural factors contribute to erosion.
• Nutrient depletion: Continuous cultivation of crops without proper nutrient management leads to the depletion of essential nutrients in the soil, reducing its fertility.
• Salinization: Over-irrigation and poor drainage can cause the accumulation of salts in the soil, rendering it unsuitable for crop growth.
• Chemical pollution: Excessive use of chemical fertilizers and pesticides can contaminate the soil, affecting its health and fertility.

To mitigate soil degradation, the following solutions can be implemented:

• Adoption of sustainable agricultural practices: Practices like crop rotation, cover cropping, conservation tillage, and organic farming help in improving soil health, reducing erosion, and maintaining nutrient levels.
• Efficient water management: Proper irrigation techniques, such as drip irrigation and sprinkler systems, should be employed to avoid over-irrigation and minimize waterlogging.
• Nutrient management: Balanced use of organic and inorganic fertilizers, along with soil testing and nutrient application based on crop requirements, can help prevent nutrient depletion.
• Afforestation and agroforestry: Planting trees and integrating them into agricultural systems helps in preventing erosion, improving soil structure, and enhancing biodiversity.
• Government initiatives: The government should promote and support sustainable agricultural practices through subsidies, training programs, and awareness campaigns. Implementing soil conservation policies and regulations can also play a crucial role in mitigating soil degradation.

By adopting sustainable agricultural practices, improving water management, and implementing government initiatives, the challenges associated with soil degradation in India can be effectively addressed. This will not only ensure the long-term productivity of agricultural land but also contribute to environmental conservation and food security.