Soils of India – NDA Geography PYQs

NDA 2024-II

Q. 1. Which one among the following statements with reference to the black cotton soils of India is NOT correct?

(a) The black cotton soils are also called ‘Regur’

(b) They are highly moisture retentive

(c) They are rich in lime

(d) These soils have less clay factor and hence can support a wide variety of crops and vegetables

Answer: (d) These soils have less clay factor and hence can support a wide variety of crops and vegetables

Explanation: Option (d) is the NOT correct statement. Black cotton soils are actually highly clayey: with clay content often reaching 40–60%. This high clay content is one of their defining characteristics. It causes the soil to swell when wet and crack when dry (self-ploughing action). The claim that they have “less clay factor” is incorrect. (a): Correct. Black cotton soils are called Regur. (b): Correct. They are highly moisture-retentive due to the high clay content. (c): Correct. They are rich in lime (calcium carbonate), magnesium, iron, and alumina. Concept Tested: Properties of black cotton soil: highly clayey (NOT less clay), moisture-retentive, lime-rich

Q. 2. Which of the following is found in appreciable amount in Laterite soil in India?

(a) Calcium

(b) Phosphate

(c) Potash

(d) Nitrogen

Answer: (b) Phosphate

Explanation: Laterite soils are strongly leached and are generally deficient in nitrogen, potassium (potash), calcium, and organic matter. However, due to the presence of iron phosphate compounds in some laterite deposits, phosphate may be found in appreciable quantities in certain laterite soils. The source records Phosphate as the correct answer. Students should verify this against the official NDA 2024-II answer key, as standard Geography texts generally describe laterite soils as poor in phosphate as well. The presence of iron-phosphate minerals in some laterites may explain this answer. Concept Tested: Mineral content found in laterite soil: source records phosphate as the answer

Q. 3. Consider the following statements regarding soils:

1. Soils having a very high content of sodium and calcium and pH of more than 7.0 are alkaline soils.

2. Black cotton soil had developed on the Deccan basaltic lava under hot and humid conditions.

3. Laterite soils are characterised by a deep weathered layer from which silica has been leached.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (a) 1 only

Explanation: Statement 1 (alkaline soils: high sodium, calcium, pH > 7): Correct. Alkaline soils are characterised by a pH above 7, typically due to high sodium carbonate, calcium, and magnesium content. This is standard soil science. Statement 2 (Black cotton soil: Deccan basalt, hot and humid): Geographically accurate by standard sources. However, the source answer records this as incorrect. Students should verify against the official NDA 2024-II answer key. Statement 3 (Laterite: silica leached, deep weathered layer): Also geographically accurate by standard sources. Laterisation involves the leaching of silica, leaving iron and aluminium compounds. However, the source answer records this as incorrect as well. The source answer is (a) 1 only. Students should verify statements 2 and 3 against the official NDA 2024-II answer key before relying on this answer. Concept Tested: Soil properties: alkaline soils (pH > 7); source records only Statement 1 as correct

NDA 2024-I

Q. 4. Which of the following statements regarding Regur soil is/are correct?

1. It is a light coloured, clayey and fertile soil.

2. It is developed on Deccan basaltic lava under hot and humid conditions.

3. Cotton is extensively cultivated in this soil.

Select the answer using the code given below:

(a) 1 and 2

(b) 2 and 3

(c) 1 and 3 only

(d) 3 only

Answer: (b) 2 and 3

Explanation: Statement 1 (light coloured, clayey and fertile): Incorrect. Regur is dark (black or dark grey) in colour: not light coloured. It is indeed clayey and fertile, but the description “light coloured” makes this statement incorrect. Statement 2 (developed on Deccan basaltic lava under hot and humid conditions): Correct. Regur soil forms from the weathering of Deccan Trap basalt. The volcanic basalt rock, under conditions of seasonal hot and humid climate, weathers over a long period to produce this deep, dark, moisture-retentive soil. Statement 3 (cotton extensively cultivated): Correct. Regur is specifically called “Black Cotton Soil” because cotton is the primary crop grown in it across Maharashtra, Madhya Pradesh, Gujarat, and Andhra Pradesh. Concept Tested: Properties of Regur soil: dark colour, basaltic origin, and association with cotton cultivation

NDA 2023-II

Q. 5. Which one of the following soils is ideal for growing cotton?

(a) Regur soil

(b) Laterite soil

(c) Desert soil

(d) Mountainous soil

Answer: (a) Regur soil

Explanation: Regur soil (Black Cotton Soil) is ideal for growing cotton. This soil type has very high clay content and excellent moisture-retaining capacity. It remains moist even during dry periods, supporting the long growing season cotton requires. Laterite soil is poor in nutrients and not suitable for cotton. Desert soil is dry and nutrient-poor. Mountainous soil is thin and rocky: unsuitable for commercial cotton cultivation. Concept Tested: Regur soil as the ideal soil type for cotton cultivation: moisture retention and clay content

NDA 2023-I

Q. 6. The process of Podsolization is predominantly found in:

(a) Equatorial forest

(b) Monsoon forest

(c) Taiga forest

(d) Mediterranean forest

Answer: (c) Taiga forest

Explanation: Podsolization (also spelled Podzolisation) is a soil-forming process that occurs in cold, humid climates with coniferous forest (Taiga/Boreal forest) vegetation. In Taiga forests, acidic leaf litter from conifers makes rainwater acidic. This acidic water leaches iron, aluminium, and organic matter downward from the upper soil layers, leaving a distinctive grey-white (ash-like) layer called the “eluvial horizon” or “E horizon”. Equatorial forests produce laterisation (not podsolization). Monsoon forests produce a range of processes depending on conditions. Mediterranean forests tend toward red or brown soil processes. Concept Tested: Podsolization: soil-forming process in cold coniferous Taiga forests through acid leaching

Q. 7. In the soil-forming regime, which one of the following occurs in a region where evapotranspiration exceeds precipitation significantly?

(a) Calcification

(b) Laterization

(c) Podsolization

(d) Gleization

Answer: (a) Calcification

Explanation: When evapotranspiration significantly exceeds precipitation, water moves upward through the soil (capillary rise) rather than downward. Calcium and other minerals are carried upward and deposited in upper soil horizons. This process is called Calcification. It produces calcium-rich (calcareous) soils: typical of semi-arid and arid regions like Rajasthan and parts of the American Midwest. Laterization occurs in hot, high-rainfall regions (opposite conditions). Podsolization occurs in cold, acidic forest conditions. Gleization occurs in waterlogged conditions with poor drainage. Concept Tested: Calcification: soil process in arid/semi-arid regions where evapotranspiration exceeds precipitation

★ JOVIK Exam Insight The four main soil-forming regimes and their climate conditions: Calcification → arid/semi-arid (evapotranspiration > precipitation; salts accumulate upward). Laterization → humid tropical (heavy leaching; iron and aluminium oxides remain). Podsolization → cold humid coniferous forest (acidic leaching; grey eluvial layer). Gleization → waterlogged, poorly drained regions (anaerobic conditions; grey/blue soil colours).

NDA 2021-II

Q. 8. Which one of the following is not a soil forming factor?

(a) Parent material

(b) Topography

(c) Climate

(d) Human habitation

Answer: (d) Human habitation

Explanation: The five recognised soil-forming factors (Jenny’s factors) are: Parent material, Climate, Organisms (vegetation and fauna), Topography (relief), and Time. Human habitation is not one of the classical soil-forming factors. Humans can modify soils (through agriculture, urbanisation, contamination) but this is not classified as a natural soil-forming factor. Parent material (a): the rock or mineral from which soil develops. Climate (c): drives weathering, leaching, and biological activity. Topography (b): affects drainage, erosion, and sunlight exposure. Concept Tested: Classical soil-forming factors: parent material, climate, organisms, topography, time; human habitation is not one

NDA 2016-II

Q. 9. Statement I: The laterite soils develop in areas with high temperature and high rainfall.

Statement II: Laterite soils are the result of intense leaching process.

(a) Both the statements are individually true and Statement II is the correct explanation of Statement I

(b) Both the statements are individually true but Statement II is not the correct explanation of Statement I

(c) Statement I is true but Statement II is false

(d) Statement I is false but Statement II is true

Answer: (a) Both the statements are individually true and Statement II is the correct explanation of Statement I

Explanation: Statement I: Correct. Laterite soils form in tropical and subtropical areas with high temperature and heavy rainfall. They are typical of the Western Ghats, Malabar coast, northeastern states, parts of Odisha, and the hills of south India. Statement II: Correct. Laterite soils are formed by the process of laterisation: intense leaching by heavy rainfall. Leaching removes soluble minerals like silica, calcium, and magnesium. What remains is a soil enriched in iron and aluminium oxides, giving it a reddish brick-like colour. Statement II explains Statement I: the high temperature and rainfall directly cause the intense leaching (laterisation) that produces these soils. Concept Tested: Laterite soil formation: intense leaching in high temperature and high rainfall conditions

★ JOVIK Exam Insight Laterite soil facts for NDA: “Laterite” comes from the Latin word “later” meaning brick. It is brick-red in colour due to iron and aluminium oxides. It is poor in nitrogen, phosphorus, and potassium. Intense leaching removes nutrients. It is found on the Western Ghats slopes, northeastern highlands, and parts of the Eastern Ghats. It is not suitable for agriculture without heavy manuring.

NDA 2015-II

Q. 10. The term ‘Regur’ is used to mean:

(a) Laterite soil

(b) Deltaic soil

(c) Red soil

(d) Black cotton soil

Answer: (d) Black cotton soil

Explanation: “Regur” is the local term for Black Cotton Soil in India. It is derived from a Sanskrit-origin word and is used extensively in Indian Geography textbooks. Regur soil is the dominant soil type of the Deccan Plateau, found across Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and Telangana. It is dark coloured, highly clayey (can hold up to 60% clay), moisture-retentive, and rich in calcium and magnesium: ideal for cotton cultivation. Concept Tested: Regur: the local term for Black Cotton Soil in India

Q. 11. Which one of the following statements is not correct?

(a) Application of lime makes the soil acidic

(b) High acidity in soil is typical of humid climate

(c) Increasing soil acidity results in declining soil fertility

(d) Arid climate is characterized by alkaline soil

Answer: (a) Application of lime makes the soil acidic

Explanation: Option (a) is incorrect: and therefore the answer to the “not correct” question. Lime (calcium carbonate or calcium oxide) is an alkaline substance. When applied to soil, it neutralises acidity and raises the pH, making the soil more alkaline: not acidic. Liming is a standard agricultural practice to correct soil acidity. Option (b): Correct. In humid climates, heavy rainfall leaches calcium and other basic elements, leaving behind acidic soils. Correct. Option (c): Correct. High acidity interferes with nutrient availability and microbial activity, reducing soil fertility. Correct. Option (d): Correct. In arid climates, low rainfall prevents leaching. Salts and calcium accumulate, making soils alkaline (often saline or calcareous). Correct. Concept Tested: Lime application raises soil pH (alkaline effect): not acidic; soil acidity in humid vs. arid climates

NDA 2014-I

Q. 12. Mulching, an agronomic measure of soil conservation, is very effective because it:

1. protects soil from gully erosion

2. protects soil from sheetwash and wind erosion

3. helps soil to retain moisture and nutrients

Select the correct answer using the code given below:

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (c) 2 and 3 only

Explanation: Mulching involves covering the soil surface with organic matter (straw, leaves, compost) or synthetic materials. Statement 1 (protects from gully erosion): Incorrect. Gully erosion involves concentrated flow of water cutting deep channels. Mulch does not prevent this; structural measures like check dams or contour bunding are needed. Statement 2 (protects from sheetwash and wind erosion): Correct. Mulch forms a protective layer on the soil surface that prevents raindrops from directly hitting and displacing soil (sheetwash). It also reduces wind velocity at the surface and prevents wind erosion. Statement 3 (retains moisture and nutrients): Correct. Mulch slows evaporation, keeping soil moist. As it decomposes, it adds organic matter and nutrients to the soil. Concept Tested: Mulching for soil conservation: effective against sheetwash and wind erosion, and for moisture retention

NDA 2008-I

Q. 13. Which one of the following soils is most suitable for cotton cultivation?

(a) Red soil

(b) Black soil

(c) Loamy soil

(d) Laterite soil

Answer: (b) Black soil

Explanation: Black soil (also called Regur or Black Cotton Soil) is the most suitable for cotton cultivation. It is rich in calcium carbonate, magnesium, potash, and lime. It has a high moisture-retaining capacity: crucial for cotton, which needs a long growing season. Black soil is formed from the weathering of Deccan Trap basaltic rock over millions of years. Red soil is suitable for millets and pulses. Laterite soil is poor in nutrients. Loamy soil supports many crops but is not specifically associated with cotton. Concept Tested: Black/Regur soil as the most suitable soil type for cotton cultivation

★ JOVIK Exam Insight Black soil and cotton is one of the most repeated NDA Geography combinations. It appears in NDA 2008-I, 2015-II, 2023-II, and 2024-I and 2024-II. The key terms: Regur, Black Cotton Soil, Deccan Trap basalt, moisture-retentive, calcium-rich: must all be associated together.

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