Soils of India – NDA Geography PYQs

Question 1 [NDA 2008-I]
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
Black soil (Regur) is called Black Cotton Soil precisely because it is the most suitable soil for growing cotton. It retains moisture well — cotton plants need sustained moisture. It is rich in calcium and magnesium. Red and laterite soils are too poor in nutrients. Loamy soil is good for general farming but not specifically best for cotton.

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Question 2 [NDA 2014-I]
Mulching, an agronomic measure of soil conservation, is very effective because it:

1. Protects soil from gully erosion
2. Protects soil from sheet wash and wind erosion
3. Helps soil to retain moisture and nutrients

(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3

Answer: (c) 2 and 3 only
Mulching is the practice of covering soil with organic material. It protects soil surface from sheet wash and wind erosion (2 is correct). It also helps soil retain moisture and nutrients (3 is correct). However, mulching does NOT protect soil from gully erosion — gullies are formed by concentrated fast-flowing water that breaks through surface cover (1 is wrong).

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Question 3 [NDA 2015-II]
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 characterised by alkaline soil

Answer: (a) Application of lime makes the soil acidic
This is the incorrect statement. Lime (calcium carbonate or calcium hydroxide) is alkaline in nature. When added to acidic soil, it NEUTRALISES the acidity — it makes the soil LESS acidic (raises pH). The other three statements are correct — humid climates produce acidic soils; high acidity reduces fertility; arid climates produce alkaline soils.

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Question 4 [NDA 2015-II]
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
Regur is the local/technical name for Black Cotton Soil. It is the dark-coloured soil of the Deccan Plateau, formed from weathered basaltic lava. It is best suited for growing cotton.

Question 5 [NDA 2016-II]
Consider the following statements:
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 true; Statement II explains Statement I
(b) Both true; Statement II does not explain Statement I
(c) Statement I true; Statement II false
(d) Statement I false; Statement II true

Answer: (a) Both true; Statement II explains Statement I
Both statements are correct. Laterite soils form in hot and rainy conditions. The intense rainfall causes intense leaching — washing away silica and soluble minerals, leaving behind iron and aluminium oxides. Statement II correctly explains why Statement I is true — high rainfall causes the leaching that forms laterite soil.

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Question 6 [NDA 2021-II]
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
The five natural factors of soil formation are: parent material (parent rock), climate, relief (topography), vegetation, and time. Human habitation uses and modifies soil but is not a natural soil-forming factor. Humans arrived recently in geological terms and cannot create soil — they can only degrade or improve it.

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Question 7 [NDA 2023-I]
The process of Podsolization is predominantly found in:
(a) Equatorial forest
(b) Monsoon forest
(c) Taiga forest
(d) Mediterranean forest

Answer: (c) Taiga forest
Podsolisation occurs in cold, humid conditions with coniferous forests (Taiga forests). Intense leaching under cold and acidic conditions from conifer needles creates nutrient-poor, acidic podzol soils. This process is typical of Siberia, Canada, and Scandinavia — regions with boreal/taiga forests.

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Question 8 [NDA 2023-I]
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
When evapotranspiration is greater than rainfall, the soil loses moisture upward. As water moves up through the soil and evaporates, it deposits calcium carbonate (calcite) near the soil surface. This process is called calcification. It occurs in dry and semi-arid regions. Laterisation occurs where rainfall is heavy. Podsolisation occurs in cold, humid forests.

Question 9 [NDA 2023-II]
Which one of the following is ideal for growing cotton?
(a) Regur soil
(b) Laterite soil
(c) Desert soil
(d) Mountainous soil

Answer: (a) Regur soil
Regur soil (Black Cotton Soil) is the most suitable soil for cotton cultivation. It retains moisture well — cotton needs sustained water supply. It is rich in calcium and magnesium. Laterite soil is too acidic and nutrient-poor. Desert soil is too dry and sandy. Mountainous soil is too thin and rocky.

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Question 10 [NDA 2024-I]
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.

(a) 1 and 2
(b) 2 and 3
(c) 1 and 3 only
(d) 3 only

Answer: (b) 2 and 3
Statement 1 is wrong — Regur soil is dark/black in colour, NOT light-coloured. Statement 2 is correct — it develops on Deccan basaltic lava under hot and humid conditions. Statement 3 is correct — cotton is the main crop of Regur soil.

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Question 11 [NDA 2024-II]
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

Answer: (d) These soils have less clay factor and hence can support a wide variety of crops
Black cotton soils have a HIGH clay factor — NOT less clay. The high clay content is what makes them moisture retentive, sticky when wet, and good for cotton. Options (a), (b), and (c) are all correct about black cotton soil.

Question 12 [NDA 2024-II]
Consider the following statements regarding soils:

1. Soils having a very high content of sodium and calcium and pH of more than 7 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.

(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3

Answer: (a) 1 only
Statement 1 is correct — alkaline soils have high sodium, calcium, and pH above 7. Statement 2 is correct — black cotton soil did develop on Deccan basaltic lava. Statement 3 — laterite soils do involve leaching of silica, but the description “deep weathered layer” and exact characterisation may be disputed. The PYQ answer is (a) — only statement 1 is correct, suggesting statements 2 and 3 have issues in precise wording.

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Question 13 [NDA 2024-II]
Which of the following is found in appreciable amount in Laterite soil in India?
(a) Calcium
(b) Phosphate
(c) Potash
(d) Nitrogen

Answer: None of the above ideally — but based on relative presence
All four minerals — calcium, phosphate, potash, and nitrogen — are deficient in laterite soil due to heavy leaching. This appears to be a trick question where the student must know that none of these are found in appreciable amounts in laterite soil. Laterite is rich only in iron and aluminium. The question tests the fact that laterite soils are deficient in ALL the listed nutrients.