Soils of India

Q143. Which Peninsular Plateau region has black soil produced through the weathering of volcanic rock?

[DSSSB Court Attendant (2 June 2026, Shift 1)]

• (A) Western Ghats
• (B) Deccan Trap
• (C) Central Highlands
• (D) Chota Nagpur Plateau

Answer: (B) Deccan Trap

Explanation: The Deccan Trap developed from extensive basaltic lava flows. Weathering of these rocks produces the clay-rich black or regur soil. Its capacity to retain moisture helps agriculture, especially cotton cultivation across western and central parts of the peninsula.

Q142. Which Indian physiographic region combines extensive fertile alluvial deposits with a dense population?

[SSC GD Constable (20 May 2026, Shift 2)]

• (A) Peninsular Plateau
• (B) Northern Plains
• (C) Coastal Plains
• (D) Himalayas

Answer: (B) Northern Plains

Explanation: The Indus, Ganga and Brahmaputra river systems deposited enormous quantities of alluvium in the Northern Plains. Their flat terrain, fertile soils and accessible water favor intensive farming and settlements, helping explain the region’s unusually high population density.

Q141. Which crop-region association is characteristic of the regur-soil belt?

[SSC GD Constable (18 May 2026, Shift 1)]

• (A) Jute—upland desert
• (B) Cotton—black-soil basins
• (C) Tea—arid plains
• (D) Rice—dry sand dunes

Answer: (B) Cotton—black-soil basins

Explanation: Black cotton soil has high clay content and retains water for long periods. Such conditions support cotton in the basaltic Deccan region. Other crops also grow there, but the cotton–regur association remains a defining feature of Indian agricultural geography.

Q140. Which soil retains moisture particularly well and is commonly linked with cotton cultivation?

[RRB NTPC UG CBT-I (7 May 2026, Shift 2)]

• (A) Black soil
• (B) Laterite soil
• (C) Sandy soil
• (D) Red soil

Answer: (A) Black soil

Explanation: Regur or black soil swells on wetting and shrinks into wide cracks on drying. Its fine clay particles retain water, helping crops withstand intermittent dry spells. The soil is widespread on basalt-derived landscapes of the Deccan Plateau.

Q139. The mixed red-and-black soil belt of Rajasthan chiefly includes which districts?

[Rajasthan Police SI, GK & GS Paper II (6 April 2026)]

• (A) Bhilwara and Chittorgarh
• (B) Barmer and Balotra
• (C) Ajmer and Tonk
• (D) Nagaur and Jhunjhunu

Answer: (A) Bhilwara and Chittorgarh

Explanation: Mixed red and black soils occur in parts of southern and south-eastern Rajasthan where terrain and parent materials vary. Bhilwara and Chittorgarh represent this transitional zone, contrasting with the sandier, arid soils dominant across much of western Rajasthan.

Q138. Under USDA soil taxonomy, which soil order occupies the largest area in India?

[Rajasthan Police SI, GK & GS Paper II (5 April 2026)]

• (A) Entisols
• (B) Inceptisols
• (C) Alfisols
• (D) Vertisols

Answer: (B) Inceptisols

Explanation: Inceptisols display relatively weak or beginning soil-horizon development. They are extensively distributed over Indian landscapes, including river basins and hill slopes. The USDA classification differs from familiar geographical groups such as alluvial, black, red and laterite soils.

Q137. Which description correctly identifies the Great Indian Desert?

[DSSSB PRT (31 March 2026, Shift 1)]

• (A) Humid northeast with alluvial soil
• (B) East of Aravallis with dense wet forests
• (C) Northwestern arid zone with sandy soils
• (D) Southern volcanic region with black soil

Answer: (C) Northwestern arid zone with sandy soils

Explanation: The Thar Desert lies mainly in northwestern India, especially Rajasthan. Scarce rainfall, substantial evaporation and wind action favor sandy or arid soils. These conditions contrast with the river-deposited alluvium of northern plains and basalt-derived soils of the Deccan.

Q136. Which activity upsets the natural balance between the formation and loss of soil?

[SSC MTS 2025 Paper (9 February 2026, Shift 1)]

• (A) Deforestation
• (B) Afforestation
• (C) Organic farming
• (D) Intercropping

Answer: (A) Deforestation

Explanation: Trees and ground vegetation intercept rainfall and their roots stabilize the topsoil. Removing them exposes the surface to rain splash, runoff and wind, often making erosion faster than soil formation. Afforestation, conversely, is a major protective measure.

Q135. The entire Northern Plains of India are chiefly composed of which soil?

[SSC MTS 2025 Paper (5 February 2026, Shift 2)]

• (A) Black
• (B) Laterite
• (C) Yellow
• (D) Alluvial

Answer: (D) Alluvial

Explanation: The Northern Plains consist of thick river-borne deposits carried by the Indus, Ganga, Brahmaputra and their tributaries. This alluvium contains varying proportions of sand, silt and clay. Its fertility helps sustain intensive cereal cultivation and large rural settlements.

Q134. Which apex body oversees the Indian Institute of Soil Science, Bhopal?

[RRB Group D (3 February 2026, Shift 2)]

• (A) Indian Council of Agricultural Research
• (B) Central Soil Salinity Research Institute
• (C) Council of Scientific and Industrial Research
• (D) National Horticulture Board

Answer: (A) Indian Council of Agricultural Research

Explanation: The Indian Institute of Soil Science in Bhopal functions under the Indian Council of Agricultural Research. Its research supports soil fertility, nutrient management and sustainable agricultural practices. The institute is distinct from the Central Soil Salinity Research Institute at Karnal.

Q133. Black soil in India is concentrated mainly in which geographical region?

[MP Police SI (19 January 2026, Shift 1)]

• (A) Deccan Trap
• (B) Gangetic Plains
• (C) Thar Desert
• (D) Himalayas

Answer: (A) Deccan Trap

Explanation: Basaltic rocks of the Deccan Trap weather into dark, clayey soil with high moisture-holding ability. It is common in Maharashtra and adjoining plateau states. River alluvium, not volcanic regur, dominates the extensive plains of the Ganga.

Q132. Laterite soils are ordinarily deficient in which of the following?

[MP Police SI (18 January 2026, Shift 2)]

• (A) Salt
• (B) Water
• (C) Sand particles
• (D) Plant nutrients

Answer: (D) Plant nutrients

Explanation: High rainfall and temperature cause intense leaching of soluble substances in laterite soils. Although iron and aluminium oxides remain concentrated, essential plant nutrients and humus are often scarce. Fertilizer and organic inputs are needed for productive plantation agriculture.

Q131. Which soil dominates the Northern Plains of India?

[Delhi Police Constable (6 January 2026, Shift 1)]

• (A) Alluvial soil
• (B) Black soil
• (C) Red soil
• (D) Laterite soil

Answer: (A) Alluvial soil

Explanation: The Northern Plains are built of sediments deposited by Himalayan-fed rivers over long geological periods. Alluvial soil is therefore widespread there. The fresh floodplain portion is known as khadar, while older alluvium on higher ground is called bhangar.

Q130. Which soil is characteristically associated with the Deccan Plateau?

[Delhi Police Constable (29 December 2025, Shift 1)]

• (A) Red soil
• (B) Black soil
• (C) Laterite soil
• (D) Arid soil

Answer: (B) Black soil

Explanation: Large tracts of the Deccan Plateau are covered by dark soil weathered from basaltic lava. This black or regur soil is fine-textured, clayey and moisture-retentive. It is especially important for cotton, pulses, oilseeds and other dryland crops.

Q129. Complete the geographical analogy: Alluvial soil : Indo-Gangetic Plain :: Black soil : ?

[MP Police Constable (5 December 2025, Shift 2)]

• (A) Deccan Plateau
• (B) Coastal Plains
• (C) Eastern Himalayas
• (D) Sundarbans

Answer: (A) Deccan Plateau

Explanation: Alluvial deposits are associated with major river plains, whereas black soil is mainly linked to weathered Deccan basalt. The analogy contrasts transported river sediments with residual soils developed upon volcanic rocks of western and central peninsular India.

Q128. Which soil develops in high-temperature, heavy-rainfall climates with alternating wet and dry periods?

[SSC JE Civil (3 December 2025, Shift 1)]

• (A) Black soil
• (B) Red soil
• (C) Arid soil
• (D) Laterite soil

Answer: (D) Laterite soil

Explanation: Laterisation involves strong tropical weathering and the leaching of silica and soluble bases. Iron and aluminium oxides remain concentrated, commonly producing reddish soils. The process is particularly developed in humid uplands, including parts of the Western Ghats.

Q127. What name is given to the old alluvium of the Indian river plains?

[UP Police ASI (2 November 2025)]

• (A) Terai
• (B) Peaty soil
• (C) Laterite
• (D) Bhangar

Answer: (D) Bhangar

Explanation: Bhangar is older alluvium occurring on relatively higher terraces beyond regular river flooding. It may contain calcareous kankar nodules. Khadar, by contrast, is younger alluvium refreshed by occasional floods and is generally considered more fertile.

Q126. Which soil group is typical of the Northern Plain of India?

[IB ACIO Grade II (17 September 2025, Shift 1)]

• (A) Red soil
• (B) Black soil
• (C) Laterite soil
• (D) Alluvial soil

Answer: (D) Alluvial soil

Explanation: The northern river plains accumulated vast layers of silt, clay and sand supplied by the Ganga, Brahmaputra, Indus and tributaries. Such deposited material is called alluvium. Its favorable texture and fertility sustain intensive farming across northern states.

Q125. Among calcium, nitrogen, phosphate and potash, which constituent was identified in the paper as appreciable in laterite soil?

[UPSC NDA II, General Ability Test (14 September 2025)]

• (A) Calcium only
• (B) Nitrogen only
• (C) Phosphate only
• (D) Potash only

Answer: (D) Potash only

Explanation: The examination key selects potash among the specified alternatives. Laterite is principally known for iron and aluminium oxides and extensive leaching, which often depletes nutrients. Relative nutrient descriptions depend on the reference and should not be mistaken for universal soil-fertility claims.

Q124. Which crop is most characteristically suited to black soil?

[DSSSB ASO (19 August 2025, Shift 2)]

• (A) Sugarcane
• (B) Cotton
• (C) Rice
• (D) Millet

Answer: (B) Cotton

Explanation: Black soil is called black cotton soil because its fine clay fraction stores moisture for long periods. Cotton can exploit this moisture under the seasonal rainfall regime of the Deccan. The soil also supports several cereals and oilseeds.

Q123. Which combination of seasonal temperatures and soil is best for wheat cultivation?

[SSC Stenographer (8 August 2025, Shift 3)]

• (A) Desert heat above 40°C with sandy loam
• (B) Hot and humid laterite terrain
• (C) Cool winter, mild ripening season and clay loam
• (D) Tropical heat with sandy soil

Answer: (C) Cool winter, mild ripening season and clay loam

Explanation: Wheat prefers cool growing weather and warmer, relatively dry ripening conditions. Moisture-retaining, well-structured loam or clay loam can support its roots and nutrient supply. Extreme desert heat and poorly managed sandy soils are less favorable for dependable yields.

Q122. Which statements are correct? 1. Erosion and deforestation can turn farmland into wasteland. 2. Plains occupy India’s largest relief-area share. 3. Net sown area is nearly identical across states.

[SSC Selection Post, Graduate Level (30 July 2025, Shift 3)]

• (A) 1 and 2 only
• (B) 2 and 3 only
• (C) 1 and 3 only
• (D) 2 only

Answer: (A) 1 and 2 only

Explanation: Sustained removal of vegetation and topsoil degrades once-cultivable land. Plains also constitute the largest broad relief category in India. Net sown-area shares vary markedly with terrain, climate, settlement, irrigation and land use, so the third statement is incorrect.

Q121. In which Indian region is alluvial soil most commonly distributed?

[RRB NTPC Graduate CBT-I (20 June 2025, Shift 3)]

• (A) Eastern Ghats
• (B) Peninsular Plateau
• (C) Western Ghats
• (D) Indo-Gangetic Plain

Answer: (D) Indo-Gangetic Plain

Explanation: The Indo-Gangetic Plain was constructed by sediments laid down by large river systems. These deposits form alluvial soils whose texture ranges from sandy to clayey. They support major food-grain regions because of their relatively fertile and extensive agricultural land.

Q120. Which soil is dominant in the Great Plains of India?

[RRB NTPC Graduate CBT-I (19 June 2025, Shift 2)]

• (A) Laterite soil
• (B) Black cotton soil
• (C) Alluvial soil
• (D) Red soil

Answer: (C) Alluvial soil

Explanation: India’s Great Plains are an extensive sedimentary lowland formed by river deposition. The deposited sand, silt and clay collectively produce alluvial soil. Its widespread distribution supports farming of rice, wheat, sugarcane and a variety of pulses.

Q119. Black soil occurs predominantly in which region?

[UKPSC Lower PCS Preliminary (11 May 2025)]

• (A) Chota Nagpur Plateau
• (B) Deccan Plateau
• (C) Terai region
• (D) Sundarbans

Answer: (B) Deccan Plateau

Explanation: Regur soil is associated with the Deccan Plateau, where basaltic lava has weathered into dark clay-rich material. This mineral parentage distinguishes it from the Himalayan piedmont, the deltaic Sundarbans and much of the Chota Nagpur region.

Q118. Which major soil type has the alternative name “regur”?

[BSSC Group D (11 May 2025)]

• (A) Mountain soil
• (B) Alluvial soil
• (C) Yellow soil
• (D) Black soil

Answer: (D) Black soil

Explanation: Regur is the traditional name for black cotton soil, especially widespread in the Deccan region. The soil swells when wet, develops cracks during dry weather and retains water efficiently. These properties are important to rainfed cotton cultivation.

Q117. Which statements about saline soils in India are correct? 1. They are rich in nitrogen. 2. They occur in arid and semi-arid regions and in swampy or waterlogged places.

[UPSC CDS-I General Studies (13 April 2025)]

• (A) 1 only
• (B) 2 only
• (C) Both 1 and 2
• (D) Neither 1 nor 2

Answer: (B) 2 only

Explanation: Excess soluble salts characterize saline soils, which occur in arid districts, coastal tracts and poorly drained areas. High salt concentration does not make a soil rich in nitrogen. Such conditions hinder water absorption by plants and may require drainage and careful reclamation.

Q116. Which statements about humus are correct? 1. It is a dark, amorphous material. 2. Its colloidal character allows it to act as a nutrient reservoir.

[UPSC CDS-I General Studies (13 April 2025)]

• (A) 1 only
• (B) 2 only
• (C) Both 1 and 2
• (D) Neither 1 nor 2

Answer: (C) Both 1 and 2

Explanation: Humus is the stable, dark organic matter produced through decomposition of plant and animal residues. Its colloidal particles hold water and nutrients and support soil aggregation. These properties improve fertility and biological activity, making both given descriptions accurate.

Q115. Which pair of crops is particularly well suited to the alluvial soils of the Great Indian Plains?

[RPF Constable 2024 Paper (9 March 2025, Shift 2)]

• (A) Coffee and tea
• (B) Pulses and oilseeds
• (C) Cotton and tobacco
• (D) Rice and wheat

Answer: (D) Rice and wheat

Explanation: River-laid alluvium of the Great Indian Plains forms productive cropland with generally favorable physical properties. Alongside irrigation and a seasonal climate, these soils support intensive rice and wheat farming. The other crop pairs have different principal ecological associations.

Q114. Which statement about black soils in Madhya Pradesh is incorrect?

[MPPSC State Service Prelims (16 February 2025)]

• (A) They form through weathering of Deccan lava
• (B) They are rich in nitrogen, phosphorus and organic matter
• (C) They retain moisture very effectively
• (D) They occur mainly in western Madhya Pradesh

Answer: (B) They are rich in nitrogen, phosphorus and organic matter

Explanation: Black soils in western Madhya Pradesh are derived largely from basalt and are notably moisture-retentive. Although they contain several mineral bases, they are generally deficient in nitrogen, phosphorus and humus. Therefore, describing them as rich in all three is wrong.

Q113. Black soil is comparatively poor in which listed nutrient?

[MPTET Varg 3 (13 November 2024, Shift 1)]

• (A) Lime
• (B) Iron
• (C) Magnesia
• (D) Nitrogen

Answer: (D) Nitrogen

Explanation: The dark soils of the Deccan often contain calcium, magnesium and iron compounds but have relatively low nitrogen and organic matter. Their high clay content gives strong water retention; balanced nutrient management is nevertheless needed for sustained cultivation.

Q112. Which Indian physical feature is associated with lateritic soils and plantation crops?

[SSC MTS (5 November 2024, Shift 1)]

• (A) Chota Nagpur Plateau
• (B) Western Ghats
• (C) Himalayas
• (D) Malabar Coast

Answer: (B) Western Ghats

Explanation: The humid tropical climate and high rainfall of the Western Ghats promote leaching and laterite development. Plantation crops, including tea, coffee and rubber, are cultivated in suitable managed sites. Nutrient depletion and acidity often require careful soil management.

Q111. What term denotes the proportion of pore space in a soil or rock?

[SSC MTS (4 November 2024, Shift 3)]

• (A) Porosity
• (B) Density
• (C) Salinity
• (D) Permeability

Answer: (A) Porosity

Explanation: Porosity measures the volume fraction of voids between particles. Those spaces can contain air or water and strongly affect storage. Permeability is different: it concerns the ease with which fluids can pass through connected pores.

Q110. What description applies to soils with pH greater than 7.5?

[SSC MTS (30 October 2024, Shift 3)]

• (A) Slightly acidic
• (B) Alkaline
• (C) Strongly acidic
• (D) Neutral

Answer: (B) Alkaline

Explanation: A pH above seven indicates alkalinity; soils exceeding 7.5 are distinctly alkaline. In arid and semi-arid regions, evaporation and accumulation of soluble salts or carbonates can raise soil pH, sometimes making important micronutrients less available to crops.

Q109. Which process chiefly initiates the development of soil from rock?

[SSC MTS (18 October 2024, Shift 1)]

• (A) Weathering
• (B) Irrigation
• (C) Degradation
• (D) Mining

Answer: (A) Weathering

Explanation: Physical, chemical and biological weathering break down parent rock into mineral fragments and altered materials. Organic inputs and soil-forming organisms then help create horizons over time. Irrigation and mining may modify existing soil but are not the primary natural origin.

Q108. Which listed element becomes highly concentrated in laterite profiles?

[SSC MTS (17 October 2024, Shift 2)]

• (A) Iron
• (B) Feldspar
• (C) Nitrogen
• (D) Lime

Answer: (A) Iron

Explanation: Intense tropical leaching removes many soluble compounds while iron and aluminium oxides remain relatively concentrated. Iron compounds impart reddish coloration to many laterite soils. Nitrogen and lime are generally depleted rather than enriched by the process.

Q107. Which property expresses the ability of soil or rock to transmit a fluid?

[SSC MTS (16 October 2024, Shift 2)]

• (A) Permeability
• (B) Plasticity
• (C) Stability
• (D) Density

Answer: (A) Permeability

Explanation: Permeability describes fluid movement through connected pore spaces and depends on grain size, pore connectivity and compaction. It differs from porosity, which measures how much empty space exists. Coarse sands often permit faster drainage than dense clays.

Q106. What is the layer of loose rock debris and soil covering solid bedrock called?

[SSC MTS (9 October 2024, Shift 2)]

• (A) Talus
• (B) Regolith
• (C) Scree
• (D) Protolith

Answer: (B) Regolith

Explanation: Regolith is the blanket of unconsolidated weathered material lying above intact bedrock. It may contain fragmented rock, dust and developing soil. Talus and scree refer more specifically to accumulations of rock fragments near slopes or cliffs.

Q105. Which claim about deposits of alluvial soil is generally incorrect?

[MP Vyapam Sub Engineer Civil (23 September 2024, Shift 2)]

• (A) They form through stream-borne sediment
• (B) They commonly form extensive even ground
• (C) They often have gentle surface slopes
• (D) Hard, shallow bedrock foundations are always available

Answer: (D) Hard, shallow bedrock foundations are always available

Explanation: Alluvial terrain is built by deposition of unconsolidated river sediment, often producing flat landforms. Such deposits can be deep or compressible, so hard foundation strata are not necessarily near the surface. Engineering properties vary with sediment texture and depth.

Q104. Of calcium, phosphate, potash and nitrogen, which was identified in the NDA paper as appreciable in Indian laterite?

[UPSC NDA II, General Ability Test (1 September 2024)]

• (A) Calcium
• (B) Phosphate
• (C) Potash
• (D) Nitrogen

Answer: (C) Potash

Explanation: This multiple-choice examination selected potash relative to the other listed nutrients. The defining property of laterite remains intense leaching with enrichment of iron and aluminium oxides. Lateritic fertility varies, and many soils still require nutrient amendments for cultivation.

Q103. Halophytes typically grow in which category of soil?

[UPSC CDS-II General Knowledge (1 September 2024)]

• (A) Acidic soil
• (B) Saline soil
• (C) Black soil
• (D) Sandy soil

Answer: (B) Saline soil

Explanation: Halophytes are plants adapted to environments with high soluble-salt concentration. They occur around salt marshes, saline flats and certain coasts. Adaptations may include selective ion uptake, salt exclusion and storage in specialised tissues, unlike ordinary salt-sensitive crop plants.

Q102. Consider two statements: 1. Bajra is mainly grown in Rajasthan, Uttar Pradesh and Gujarat, whereas ragi is important in Karnataka and Tamil Nadu. 2. Bajra suits sandy and shallow black soils, while ragi suits red and shallow black soils. Which is correct?

[UPSC CDS-II General Knowledge (1 September 2024)]

• (A) Both are correct, and 2 correctly explains 1
• (B) Both are correct, but 2 does not correctly explain 1
• (C) Statement 1 only is correct
• (D) Statement 2 only is correct

Answer: (B) Both are correct, but 2 does not correctly explain 1

Explanation: Bajra tolerates drought and grows on sandy or relatively shallow soils, while ragi grows on several well-drained soils including red soil. The regional cultivation patterns are valid, but soil suitability alone does not fully explain where each millet is grown.

Q101. Which state is not part of the usual black-soil distribution?

[WBCS 2023 Mains, Paper III (18 August 2024)]

• (A) Maharashtra
• (B) Andhra Pradesh
• (C) Gujarat
• (D) West Bengal

Answer: (D) West Bengal

Explanation: Black regur soils are predominantly distributed across the Deccan and adjoining western and central Indian regions. West Bengal instead has extensive alluvial plains and lateritic tracts. This comparison highlights the geographical link between black soil and basaltic landscapes.

Q100. Statement 1: Black soil supports rainfed crops.
Statement 2: It stores moisture for extended periods.

Which relationship is correct?

[UPSC CAPF AC Paper I (4 August 2024)]

• (A) Both correct; statement 2 explains statement 1
• (B) Both correct; statement 2 does not explain statement 1
• (C) Statement 1 correct, statement 2 incorrect
• (D) Statement 1 incorrect, statement 2 correct

Answer: (A) Both correct; statement 2 explains statement 1

Explanation: The clay minerals of black soils absorb and retain considerable water, supplying crops after rainfall has stopped. This directly explains why they can be productive under rainfed cultivation. Their swelling and shrinking behavior is another familiar characteristic.

Q99. Which soil group occupies approximately forty percent of India’s area?

[SSC CHSL Tier I (2 July 2024, Shift 4)]

• (A) Red and yellow
• (B) Black
• (C) Alluvial
• (D) Laterite

Answer: (C) Alluvial

Explanation: Alluvial soils constitute the most extensive broad geographical soil group in India. They are laid down by streams and rivers, especially across the northern plains and major deltas. Different estimates vary with classification methods and mapped area.

Q98. Which physiographic division has extensive alluvial soil?

[SSC CPO Paper I (29 June 2024, Shift 1)]

• (A) Himalayan Range
• (B) North Indian Plain
• (C) Island Groups
• (D) Great Indian Desert

Answer: (B) North Indian Plain

Explanation: Rivers emerging from the Himalayas transport eroded sediment onto the broad North Indian Plain. Repeated deposition forms thick alluvial soils. By contrast, mountains are dominated by slope and forest soils, and the desert has predominantly arid sandy material.

Q97. Which statements are correct? 1. Every soil with sodium and calcium and pH above seven is termed alkaline. 2. Black soil developed over Deccan basalt. 3. Laterite has undergone deep silica leaching.

[UPSC NDA I, General Ability Test (21 April 2024)]

• (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: Black cotton soil is associated with basaltic lava, and laterite develops when prolonged tropical weathering removes silica. The first statement incorrectly uses a broad pH and composition test as a sufficient definition of problematic alkaline soils.

Q96. Which soil is especially associated with coffee plantations in the given options?

[Kolkata Police SI Preliminary (28 January 2024)]

• (A) Red soil
• (B) Alluvial soil
• (C) Black soil
• (D) Laterite soil

Answer: (D) Laterite soil

Explanation: Well-drained lateritic uplands in parts of southern India support coffee plantations under suitable rainfall and management. The soils are often acidic and leached, so organic matter and nutrients need attention. Climate, slope and shade also influence coffee cultivation.

Q95. Which state was selected as having the greatest laterite-soil extent among Uttar Pradesh, Bihar and Meghalaya?

[Bihar TRE 2.0, Social Science (9 December 2023)]

• (A) Uttar Pradesh
• (B) Bihar
• (C) Meghalaya
• (D) None of these

Answer: (C) Meghalaya

Explanation: Meghalaya has high-rainfall uplands where intense chemical weathering and leaching produce lateritic material. Uttar Pradesh and Bihar are more strongly associated with alluvial plains. The answer refers to the comparison of the particular states offered in the examination.

Q94. Which nutrient is notably deficient in black soil of the Deccan Plateau?

[SSC CPO Paper I (4 October 2023, Shift 3)]

• (A) Phosphorus
• (B) Potash
• (C) Iron
• (D) Lime

Answer: (A) Phosphorus

Explanation: Deccan black soils commonly contain lime, magnesia and several mineral bases but are relatively deficient in phosphorus and nitrogen. Their strong moisture retention does not imply balanced plant nutrition. Appropriate fertilizers and crop management may therefore be necessary.

Q93. Which crop is especially appropriate for cultivation on black soil?

[SSC MTS (11 September 2023, Shift 1)]

• (A) Soybean
• (B) Maize
• (C) Cotton
• (D) Barley

Answer: (C) Cotton

Explanation: Cotton is widely associated with black regur soils because their clay particles retain moisture during dry intervals. These soils developed largely from weathered basalt across the Deccan. Although soybean and maize can also be grown, cotton is the characteristic textbook association.

Q92. The Deccan Trap black-soil tract belongs to which Indian physiographic division?

[SSC MTS (6 September 2023, Shift 3)]

• (A) Northern Plains
• (B) Peninsular Plateau
• (C) Coastal Plains
• (D) Himalayan Mountains

Answer: (B) Peninsular Plateau

Explanation: The Deccan Trap is a basaltic volcanic province within the Peninsular Plateau. Its weathered lava supports extensive regur soil. This contrasts with the river-built Northern Plains, whose principal soil is alluvium rather than residual volcanic clay.

Q91. Which division of India was largely formed by the accumulation of alluvial deposits?

[SSC MTS (5 September 2023, Shift 2)]

• (A) Peninsular Plateau
• (B) Himalayan Mountains
• (C) Island Groups
• (D) Northern Plains

Answer: (D) Northern Plains

Explanation: The Northern Plains are a major depositional landscape receiving alluvium from Himalayan rivers. Fine material spread by streams and floods created deep fertile soils and flat surfaces. These conditions support extensive agriculture and dense settlements.

Q90. Which process is the primary cause of laterite-soil development?

[SSC MTS (5 September 2023, Shift 2)]

• (A) Compaction
• (B) Leaching
• (C) Heat acting alone
• (D) Sedimentation

Answer: (B) Leaching

Explanation: Leaching washes silica and soluble bases downward or away during heavy rainfall. Iron and aluminium oxides become concentrated, resulting in typical lateritic materials. Heat alone cannot explain the process; the combination of weathering and abundant rainfall is essential.

Q89. Which soil is comparatively rich in sodium, potassium and magnesium salts, ranges from sandy to loamy, and occurs in western Gujarat, eastern coastal deltas and the Sundarbans?

[UPSC CDS General Knowledge (3 September 2023)]

• (A) Peaty soil
• (B) Laterite soil
• (C) Arid soil
• (D) Saline soil

Answer: (D) Saline soil

Explanation: Saline soils accumulate soluble salts where evaporation, seawater influence or inadequate drainage concentrates dissolved minerals. These occur in western Gujarat and parts of coastal eastern India. Salinity makes water uptake difficult for many crops and reduces productivity without suitable management.

Q88. Which Indian soil develops through the weathering of basalt lava?

[MP Police Constable (23 August 2023, Shift 1)]

• (A) Red soil
• (B) Alluvial soil
• (C) Laterite soil
• (D) Regur soil

Answer: (D) Regur soil

Explanation: Regur is black cotton soil produced in large part through weathering of basaltic volcanic rocks. It is characteristic of the Deccan region and is recognized by its dark colour, high clay content, pronounced dry-season cracking and water storage.

Q87. Wind-deposited soil material made mainly of silt and dust is termed what?

[SSC CHSL Tier I (14 August 2023, Shift 2)]

• (A) Loam
• (B) Marl
• (C) Loess
• (D) Podzol

Answer: (C) Loess

Explanation: Loess is a wind-blown accumulation of fine, predominantly silt-sized particles. It differs from loam, which refers to a mixed soil texture, and from podzol, which describes a characteristic leached soil profile. Wind deposits can be fertile but erosion-prone.

Q86. Which constituent explains the reddish colour commonly observed in red soils?

[HSSC CET Group C Mains, Group 56 (7 August 2023)]

• (A) Potash and magnesia
• (B) Iron compounds
• (C) Overgrazing
• (D) None of these

Answer: (B) Iron compounds

Explanation: Ferric iron oxides such as hematite impart red colours to many weathered soils. They commonly form on crystalline rocks in parts of peninsular India. The colour is a mineralogical characteristic rather than a direct result of grazing or potash content.

Q85. Red soil mainly owes its characteristic colour to which substance?

[HSSC CET Group C Mains, Group 57 (6 August 2023)]

• (A) Overgrazing
• (B) Iron oxide
• (C) Potash and magnesia
• (D) None of these

Answer: (B) Iron oxide

Explanation: Iron-bearing minerals oxidize during rock weathering and create reddish ferric oxides. This is the principal reason red soils appear red. Such soils are extensive in parts of southern and eastern peninsular India, often developed from old crystalline rocks.

Q84. Which region is the characteristic black-soil region of India?

[SSC CGL Tier I (18 July 2023, Shift 1)]

• (A) Coastal Plains
• (B) Northern Plains
• (C) Deccan Trap
• (D) Himalayas

Answer: (C) Deccan Trap

Explanation: Black soil is most strongly associated with the basaltic Deccan Trap. Long-term weathering of the volcanic material produced extensive dark, clay-rich soils. These soils are important for cotton and other crops because of their substantial moisture retention.

Q83. Which soil horizon or layer normally contains the greatest concentration of humus?

[SSC MTS 2022 Paper (19 June 2023, Shift 1)]

• (A) Weathered rock
• (B) Topsoil
• (C) Parent rock
• (D) Subsoil

Answer: (B) Topsoil

Explanation: Topsoil receives decaying leaves, roots and other organic residues that microorganisms transform into humus. It is generally the biologically active soil layer. Subsoil and parent rock contain less incorporated organic material, though actual profiles vary with vegetation and climate.

Q82. Which soil is known by the name regur?

[SSC MTS 2022 Paper (17 May 2023, Shift 3)]

• (A) Peaty soil
• (B) Alluvial soil
• (C) Laterite soil
• (D) Black soil

Answer: (D) Black soil

Explanation: The name regur refers to India’s black cotton soil, common across basalt-influenced regions of the Deccan. High clay content gives it distinctive swelling, shrinking and moisture-storage properties. These characteristics help explain its connection with cotton agriculture.

Q81. Laterite-type soil occurs in which Rajasthan district?

[RPSC Executive Officer / Revenue Officer (14 May 2023, Shift 1)]

• (A) Churu
• (B) Jodhpur
• (C) Karauli
• (D) Dungarpur

Answer: (D) Dungarpur

Explanation: Dungarpur in southern Rajasthan experiences conditions more favorable to lateritic weathering than the arid northwestern districts listed. High rainfall and long-term leaching concentrate iron and aluminium compounds. Nearby Banswara is another locality where lateritic soils are reported.

Q80. Red-yellow soil is found in which Rajasthan district?

[RPSC Executive Officer / Revenue Officer (14 May 2023, Shift 2)]

• (A) Bundi
• (B) Baran
• (C) Kota
• (D) Sawai Madhopur

Answer: (D) Sawai Madhopur

Explanation: The red-yellow soil category occurs around parts of Sawai Madhopur. Iron compounds contribute the characteristic red or yellow shades, influenced by oxidation and drainage. Distribution varies with underlying rock and local weathering, so the district association is more precise than a statewide generalization.

Q79. Which soil shows natural self-ploughing through the formation of drying cracks?

[SSC MTS 2022 Paper (11 May 2023, Shift 3)]

• (A) Red soil
• (B) Laterite soil
• (C) Peaty soil
• (D) Black soil

Answer: (D) Black soil

Explanation: Black soil expands when wetted and shrinks when dry. This shrinking creates wide, deep cracks that aerate the soil profile, earning it the description self-ploughing. The phenomenon results from expansive clay minerals rather than mechanical cultivation.

Q78. Which soil is composed of varying proportions of sand, silt and clay, contains lime and potash, and is classified by age?

[UPSC CDS General Knowledge (16 April 2023)]

• (A) Alluvial soil
• (B) Laterite soil
• (C) Arid soil
• (D) Black soil

Answer: (A) Alluvial soil

Explanation: Alluvial soils form from sediments carried and deposited by rivers. The proportions of sand, silt and clay differ by locality. Indian geography distinguishes newer khadar from older bhangar alluvium, reflecting depositional age and floodplain position.

Q77. What soil type forms most of India’s Northern Plains?

[SSC CHSL 2022 Paper (20 March 2023, Shift 4)]

• (A) Alluvial
• (B) Peaty
• (C) Black
• (D) Laterite

Answer: (A) Alluvial

Explanation: Alluvial material transported by the major northern rivers accumulated in the broad plains south of the Himalayas. These deposits vary in texture and age. Younger floodplain alluvium is khadar, while older deposits on higher surfaces are bhangar.

Q76. Which statement concerning laterite soil is incorrect?

[SSC CHSL 2022 Paper (20 March 2023, Shift 4)]

• (A) Some southern laterites suit cashew
• (B) It is normally rich in humus
• (C) Tea and coffee can be cultivated on managed laterites
• (D) It develops under high rainfall and temperature

Answer: (B) It is normally rich in humus

Explanation: Laterite soils are highly leached in humid tropical climates and are frequently poor in humus and plant nutrients. With suitable amendments, irrigation and management, certain lateritic regions support tea, coffee and cashew cultivation despite their natural low fertility.

Q75. Assess two claims: I. Forest soils may be loamy and silty along valley sides. II. Black soils tend to be phosphorus-deficient.

[SSC CHSL 2022 Paper (14 March 2023, Shift 4)]

• (A) Both I and II
• (B) Only I
• (C) Only II
• (D) Neither I nor II

Answer: (A) Both I and II

Explanation: Forest soils differ with altitude and slope, and valley sides may develop loamy or silty textures. Deccan black soils contain substantial clay and mineral bases but commonly lack phosphorus. Both statements are therefore consistent with standard Indian soil descriptions.

Q74. Which soil-forming factor was identified in the paper as determining the accumulation and mineral character of soil?

[SSC CHSL 2022 Paper (14 March 2023, Shift 1)]

• (A) Fauna
• (B) Flora
• (C) Parent rock
• (D) Relief

Answer: (C) Parent rock

Explanation: Parent material provides the original mineral constituents from which a soil develops, influencing texture, chemistry and colour. Relief, climate and living organisms also affect soil formation, but the composition of the underlying rock provides the initial mineral framework.

Q73. Two statements say sandy soil has more fine particles and clayey soil more large particles. Which is correct?

[SSC CHSL 2022 Paper (13 March 2023, Shift 4)]

• (A) Only the sandy-soil statement
• (B) Neither statement
• (C) Both statements
• (D) Only the clayey-soil statement

Answer: (B) Neither statement

Explanation: Sand consists of relatively coarse mineral grains, whereas clay particles are extremely fine. Thus, both proposed associations reverse the actual particle-size relationship. Particle size greatly influences infiltration, aeration and water retention in agricultural soils.

Q72. What is the name of the exceptionally porous belt at the Shivalik foothills where streams commonly disappear underground?

[RPSC Senior Teacher Grade II GK (12 February 2023, Shift 1)]

• (A) Bhabhar
• (B) Tarai
• (C) Dhands
• (D) Dhoros

Answer: (A) Bhabhar

Explanation: The Bhabhar belt is made of coarse gravelly alluvium laid down by streams descending from the Shivaliks. Water infiltrates its large pores, making many channels disappear temporarily. Streams often re-emerge farther south in the wetter, finer-textured Tarai zone.

Q71. In which city is the Indian Institute of Soil Science located?

[SSC CGL Tier I (12 December 2022, Shift 3)]

• (A) Porbandar
• (B) Bhopal
• (C) Visakhapatnam
• (D) Bhubaneswar

Answer: (B) Bhopal

Explanation: The Indian Institute of Soil Science is located in Bhopal, Madhya Pradesh, and operates within the ICAR system. Its work supports research into soil management, crop nutrition and fertility. It should not be confused with soil-salinity research facilities at Karnal.

Q70. Which statement about soil-forming factors is incorrect?

[RRB Group D (29 September 2022, Shift 2)]

• (A) Temperature and rainfall affect weathering
• (B) Time influences soil-profile development
• (C) Parent rock can influence soil colour
• (D) Altitude and slope directly determine humus formation rate

Answer: (D) Altitude and slope directly determine humus formation rate

Explanation: Humus formation mainly depends on organic residues, microorganisms, moisture and temperature. Altitude and slope influence these indirectly through climate, vegetation and runoff, but they are not the sole direct determinants. Parent material influences many inherited mineral properties.

Q69. Which soil covers about forty percent of India’s geographical area?

[RRB Group D (27 September 2022, Shift 3)]

• (A) Alluvial
• (B) Black
• (C) Red and yellow
• (D) Laterite

Answer: (A) Alluvial

Explanation: Alluvial soils are the most widespread of the familiar Indian soil groups. They occupy large river valleys, the northern plains and several coastal deltas. They consist of transported sediments and support intensive agriculture owing to generally favorable properties.

Q68. Which option is an abiotic part of an ecosystem?

[RRB Group D (14 September 2022, Shift 2)]

• (A) Fungi
• (B) Soil
• (C) Microorganisms
• (D) Insects

Answer: (B) Soil

Explanation: Soil is classified as an abiotic environmental component even though it contains living organisms. Its nonliving matrix of minerals, water, gases and organic material provides a medium for plant growth. Fungi, insects and microorganisms themselves are biotic constituents.

Q67. Which is not a biotic ecosystem component?

[RRB Group D (18 August 2022, Shift 1)]

• (A) Frog
• (B) Flower
• (C) Insect
• (D) Soil

Answer: (D) Soil

Explanation: An ecosystem contains biotic organisms and abiotic conditions. Frogs, flowers and insects are living components, whereas soil as an environmental medium is grouped with air, water and minerals. Soil may house many organisms, but that does not change its category in this question.

Q66. Which soil mainly forms the Northern Plains of India?

[SSC MTS (25 July 2022, Shift 2)]

• (A) Laterite
• (B) Arid
• (C) Alluvial
• (D) Black

Answer: (C) Alluvial

Explanation: Alluvial soil is formed through the accumulation of river-transported sediment. Large Himalayan river systems deposited sand, silt and clay over the northern lowlands. Older alluvium is known as bhangar, and relatively young floodplain deposits are called khadar.

Q65. Which factor most strongly determines the initial mineral content, texture and colour of soil?

[SSC MTS (22 July 2022, Shift 1)]

• (A) Parent rock
• (B) Time
• (C) Relief
• (D) Climate

Answer: (A) Parent rock

Explanation: The parent rock or sediment supplies the original minerals from which a soil develops. Its composition and grain characteristics influence colour, chemistry and texture. Climate, time, organisms and relief subsequently transform the material into a differentiated soil profile.

Q64. Which listed item is not one of the five standard soil-forming factors?

[DSSSB PRT (20 March 2022, Shift 1)]

• (A) Soil composition
• (B) Parent material
• (C) Time
• (D) Climate

Answer: (A) Soil composition

Explanation: Standard soil-forming factors include climate, organisms, relief or topography, parent material and time. Soil composition is largely an outcome of those factors rather than a separate independent factor. Their relative influence determines soil properties across differing landscapes.

Q63. Which statement is incorrect if it claims to describe the composition of soil completely?

[SSC GD Constable (9 December 2021, Shift 1)]

• (A) Soil contains only inorganic matter
• (B) Soil covers much of Earth’s land surface
• (C) Soil is commonly a granular surface layer
• (D) Soil contains minerals

Answer: (A) Soil contains only inorganic matter

Explanation: Natural soil contains both mineral particles and organic constituents, alongside air, water and living organisms. Therefore, describing it as purely inorganic is incomplete. The balance of its components determines texture, nutrient cycling, water storage and biological productivity.

Q62. Among clay, sand, silt and loam, which soil material typically retains the greatest amount of water?

[SSC GD Constable (6 December 2021, Shift 1)]

• (A) Clay
• (B) Sand
• (C) Silt
• (D) Loam

Answer: (A) Clay

Explanation: Clay consists of extremely fine particles with large combined surface area and small pore spaces. It commonly holds more total water than sand or silt. Not all stored water is equally available to plants, a distinction important for irrigation decisions.

Q61. Which soil in southern Indian states is especially associated with cashew cultivation?

[SSC GD Constable (3 December 2021, Shift 3)]

• (A) Arid soil
• (B) Black soil
• (C) Alluvial soil
• (D) Red laterite soil

Answer: (D) Red laterite soil

Explanation: Red lateritic soils occur in humid, strongly weathered parts of peninsular India. Suitable sites in Kerala, Tamil Nadu and Andhra Pradesh can support cashew. Although laterites are often nutrient-poor, appropriate site conditions and management enable plantation crops.

Q60. What combination contributes directly to soil fertility?

[SSC GD Constable (18 November 2021, Shift 2)]

• (A) Excess acidity
• (B) Minerals and inorganic material alone
• (C) Suitable minerals and organic matter
• (D) High soluble-salt concentration

Answer: (C) Suitable minerals and organic matter

Explanation: Fertile soil supplies essential nutrients in usable forms while supporting roots, moisture and biological activity. A suitable balance of mineral nutrients and organic matter supports sustained plant growth. Extreme acidity or salinity can restrict nutrient availability and crop productivity.

Q59. The Northern Plains are largely formed of which material?

[SSC MTS 2020 Paper (18 October 2021, Shift 1)]

• (A) Black soil
• (B) Alluvial soil
• (C) Yellow soil
• (D) Arid soil

Answer: (B) Alluvial soil

Explanation: Major Himalayan rivers have repeatedly deposited sediment across the northern basin. The resulting alluvial soils range from sandy to clayey and are frequently fertile. Their formation differs fundamentally from the weathering of volcanic basalt that creates much black soil.

Q58. Which practice describes the mulching method of soil conservation?

[SSC MTS 2020 Paper (14 October 2021, Shift 2)]

• (A) Constructing stone contour barriers
• (B) Covering bare ground with straw or other organic matter
• (C) Alternating crop rows alone
• (D) Piling rocks across gullies

Answer: (B) Covering bare ground with straw or other organic matter

Explanation: Mulching uses a protective ground cover such as crop residues or straw. It reduces direct raindrop impact, suppresses evaporation and moderates soil temperature. Different soil-conservation methods such as contour barriers and intercropping operate through other mechanisms.

Q57. Which soil is widespread in northern river valleys and covers roughly two-fifths of India?

[SSC MTS 2020 Paper (12 October 2021, Shift 2)]

• (A) Black soil
• (B) Laterite soil
• (C) Red soil
• (D) Alluvial soil

Answer: (D) Alluvial soil

Explanation: Alluvial soils are distributed chiefly across the Northern Plains and river valleys. Rivers transport and deposit fine sediment over long periods, developing productive agricultural land. Fresh khadar occupies active floodplains, while older bhangar occurs on more elevated surfaces.

Q56. Which option is not a principal independent soil-forming factor?

[SSC CHSL 2020 Paper (12 August 2021, Shift 3)]

• (A) Topography
• (B) Parent material
• (C) Biotic agents
• (D) Cattle grazing

Answer: (D) Cattle grazing

Explanation: Climate, parent material, organisms, relief and time constitute the major soil-forming factors. Grazing can alter vegetation cover and influence erosion, but it is not listed as one of these foundational factors. Parent rock supplies the primary mineral material.

Q55. Which statement is incorrect about India’s broad alluvial-soil distribution?

[SSC CHSL 2020 Paper (12 August 2021, Shift 3)]

• (A) Old alluvium is bhangar and new alluvium khadar
• (B) Major east-coast river deltas contain alluvium
• (C) Northern plains are alluvial
• (D) All Himalayan slopes are characteristically alluvial

Answer: (D) All Himalayan slopes are characteristically alluvial

Explanation: Extensive alluvial soil occurs in plains, valleys and river deltas where transported sediment accumulates. Himalayan slopes are more usually associated with mountain and forest soils. Local valley deposits can occur, but alluvial soil does not characterize all mountain slopes.

Q54. Which soil type is associated with high humidity and heavy rainfall?

[SSC CHSL 2020 Paper (10 August 2021, Shift 3)]

• (A) Yellow
• (B) Red
• (C) Saline
• (D) Peaty

Answer: (D) Peaty

Explanation: Peaty soils accumulate substantial partly decomposed organic matter in waterlogged, humid environments. Persistently wet conditions reduce decomposition rates and allow organic deposits to build up. Their properties differ from the strongly leached laterites of well-drained humid uplands.

Q53. Which horizon mixes organic matter with minerals, nutrients and water in topsoil?

[SSC CHSL 2020 Paper (4 August 2021, Shift 1)]

• (A) C horizon
• (B) A horizon
• (C) D horizon
• (D) B horizon

Answer: (B) A horizon

Explanation: The A horizon is the mineral topsoil enriched with incorporated organic matter and active biological processes. Below it, the B horizon often accumulates transported clay and minerals. The C horizon contains relatively less altered parent material.

Q52. Which factor usually does not cause agricultural soil to lose fertility?

[SSC CHSL 2020 Paper (4 August 2021, Shift 3)]

• (A) Higher cation-exchange capacity
• (B) Alkalinisation
• (C) Salinisation
• (D) Waterlogging

Answer: (A) Higher cation-exchange capacity

Explanation: Greater cation-exchange capacity generally allows soil particles and organic matter to retain nutrient cations. By contrast, salinity, problematic alkalinity and waterlogging can restrict root growth and crop yields. Soil fertility depends on more than nutrient storage alone.

Q51. Which USDA soil order was identified as India’s largest in the National Bureau of Soil Survey classification?

[SSC CHSL 2020 Paper (16 April 2021, Shift 3)]

• (A) Aridisols
• (B) Alfisols
• (C) Inceptisols
• (D) Mollisols

Answer: (C) Inceptisols

Explanation: Inceptisols have comparatively weakly developed diagnostic horizons and occur over extensive areas of India. Their order belongs to soil taxonomy, a different system from common geographical names. Such soils may be agriculturally useful with appropriate nutrient and water management.

Q50. Which reddish tropical soil can develop through prolonged weathering of mafic igneous rock?

[SSC CHSL 2020 Paper (16 April 2021, Shift 2)]

• (A) Saline
• (B) Arid
• (C) Laterite
• (D) Pedocal

Answer: (C) Laterite

Explanation: Laterite forms under strong tropical weathering and leaching. Concentration of iron and aluminium oxides gives many lateritic deposits their reddish colour. Such weathered material can develop over different parent rocks where humid and seasonally hot conditions persist.

Q49. What kind of soil is most associated with cashew cultivation?

[SSC CHSL 2020 Paper (12 April 2021, Shift 1)]

• (A) Black
• (B) Red laterite
• (C) Red and yellow
• (D) Alluvial

Answer: (B) Red laterite

Explanation: Cashew is adapted to suitable tropical conditions and is cultivated on well-drained red lateritic soils in parts of southern India. Laterite is naturally leached and often nutrient-poor, but plantation crops can grow successfully with appropriate management.

Q48. Which statement correctly describes the distribution of black soil?

[RRB NTPC CBT-I (25 January 2021, Shift 2)]

• (A) It covers large areas of the Deccan Plateau
• (B) It is the least fertile soil everywhere
• (C) It dominates the Gangetic Plain
• (D) It is rich in nitrogen and phosphorus

Answer: (A) It covers large areas of the Deccan Plateau

Explanation: Black regur soil develops prominently over the Deccan basaltic plateau. It holds moisture well and supports cotton and several other crops. Its clay content is high, but nitrogen and phosphorus are often relatively deficient, making the remaining statements incorrect.

Q47. Match Indian soil groups with their principal states: alluvial, black, red and desert.

[UPPSC Review Officer/Assistant Review Officer Preliminary (2021)]

• (A) UP—alluvial; Maharashtra—black; Andhra Pradesh—red; Rajasthan—desert
• (B) UP—desert; Maharashtra—red; Andhra Pradesh—black; Rajasthan—alluvial
• (C) UP—black; Maharashtra—alluvial; Andhra Pradesh—desert; Rajasthan—red
• (D) UP—red; Maharashtra—desert; Andhra Pradesh—alluvial; Rajasthan—black

Answer: (A) UP—alluvial; Maharashtra—black; Andhra Pradesh—red; Rajasthan—desert

Explanation: Alluvial deposits dominate much of Uttar Pradesh, weathered Deccan basalt gives Maharashtra extensive black soils, and red soils occur in Andhra Pradesh. Rajasthan’s dry western region is associated with desert soils. These are broad regional associations rather than exclusive statewide coverage.

Q46. Statement I: Laterite forms under hot, high-rainfall conditions. Statement II: It is ordinarily very rich in humus. Which is correct?

[Jharkhand PSC Preliminary (2021)]

• (A) Only II
• (B) Both I and II
• (C) Neither
• (D) Only I

Answer: (D) Only I

Explanation: Laterite develops under intense tropical weathering and heavy rainfall that leaches many soluble compounds. Such soils are frequently low in humus and fertility. Therefore, the climatic formation statement is true, but the claim of general humus richness is false.

Q45. Black cotton soil of India originates mainly from the weathering of which rock?

[UPSC CSE Preliminary (2021)]

• (A) Brown forest soil
• (B) Fissure volcanic rock
• (C) Granite and schist
• (D) Shale and limestone

Answer: (B) Fissure volcanic rock

Explanation: Fissure eruptions produced the extensive Deccan basalt flows. Weathering of these volcanic rocks yielded the dark clayey regur soils associated with cotton. This origin contrasts with granitic red soils and river-borne alluvial material in the northern plains.

Q44. Which characteristic of Indian alluvial soil is correct among the listed claims?

[Chhattisgarh PSC Preliminary (2020)]

• (A) It covers only about fourteen percent of India
• (B) It is mineral-bearing and commonly highly fertile
• (C) It is identical to Reh or Thur saline soil
• (D) It is inherently infertile

Answer: (B) It is mineral-bearing and commonly highly fertile

Explanation: Alluvial soils are transported and deposited by rivers, producing widespread productive agricultural tracts. They typically contain useful mineral nutrients, though composition varies by basin. Reh and Thur refer to salt-affected soils, not all alluvial deposits.

Q43. Which statements about Usar soil are correct?
1. Lime is used for its reclamation.
2. Its pH exceeds seven.
3. Suitable paddy varieties can be raised on it.

[UP Block Education Officer Preliminary (2019)]

• (A) 1 and 2
• (B) 2 and 3
• (C) 3 only
• (D) 1 only

Answer: (B) 2 and 3

Explanation: Usar refers to problematic alkaline or sodic soils. Gypsum and suitable reclamation methods, not liming, help replace exchangeable sodium and improve physical conditions. Salt-tolerant paddy varieties can be cultivated after suitable management, while alkaline pH is characteristic.

Q42. Which soil is classically considered best suited for cotton?

[SSC GD Constable (6 March 2019, Shift 2)]

• (A) Black
• (B) Alluvial
• (C) Arid
• (D) Laterite

Answer: (A) Black

Explanation: Black cotton soil has high clay content, pronounced water retention and a widespread Deccan distribution. Cotton benefits from moisture stored in the soil through part of the growing season. Its characteristic physical behavior also causes deep cracks during dry periods.

Q41. Which soil is commonly sandy and saline in arid regions?

[SSC GD Constable (12 February 2019, Shift 1)]

• (A) Alluvial
• (B) Black
• (C) Laterite
• (D) Arid

Answer: (D) Arid

Explanation: Desert and arid soils are common in western Rajasthan and nearby dry regions. They are often sandy, low in humus and affected by salt accumulation because evaporation exceeds rainfall. Irrigation and careful salinity management can improve productivity on suitable land.

Q40. Which assertion about black soil is incorrect?

[UPPCS Preliminary (2018)]

• (A) It is called regur
• (B) It is moisture-retentive
• (C) It is associated with mature Deccan soils
• (D) It is characteristically located in the Himalayas

Answer: (D) It is characteristically located in the Himalayas

Explanation: Black regur soil is extensive in the basaltic Deccan and nearby central-western regions, not mainly in Himalayan mountains. Its clay-rich texture helps retain moisture. The Himalayas instead have varied shallow, mountain and forest soils according to altitude and climate.

Q39. In which Himalayan region are Karewa deposits associated with saffron cultivation?

[64th BPSC Preliminary (2018)]

• (A) Kashmir Himalaya
• (B) Garhwal Himalaya
• (C) Nepal Himalaya
• (D) Eastern Himalaya

Answer: (A) Kashmir Himalaya

Explanation: Karewas are distinctive lacustrine and associated deposits of the Kashmir Valley. Some well-drained parts support saffron cultivation, historically important in Kashmir. These deposits differ from the widespread river alluvium of the Indo-Gangetic plains.

Q38. Which soil region is a characteristic feature of the Peninsular Plateau?

[SSC Scientific Assistant, Physics (23 November 2017, Shift 2)]

• (A) Black-soil area
• (B) Laterite-only area
• (C) Red-soil-only area
• (D) Alluvial-only area

Answer: (A) Black-soil area

Explanation: Parts of the Peninsular Plateau, particularly the Deccan Trap, have extensive black cotton soils formed on basalt. The plateau has additional soil types, but the volcanic black-soil tract is a recognized distinguishing feature in Indian physical geography.

Q37. Northern Plains owe their formation chiefly to which kind of deposit?

[SSC Scientific Assistant, Physics (23 November 2017, Shift 2)]

• (A) Coral
• (B) Alluvial
• (C) Volcanic ash
• (D) Lava

Answer: (B) Alluvial

Explanation: Northern river systems transported eroded material from the Himalayas and other highlands into a subsiding basin. Accumulated alluvium built the broad plains. Coral, lava and volcanic ash do not explain the extensive sedimentary origin of this region.

Q36. Which stated goal belongs to the Soil Health Card Scheme? 1. Expand land under irrigation. 2. Set farm-bank loan ceilings. 3. Discourage excessive fertilizer use.

[UPSC CSE Preliminary (2017)]

• (A) 1 and 2 only
• (B) 3 only
• (C) 2 and 3 only
• (D) 1, 2 and 3

Answer: (B) 3 only

Explanation: The Soil Health Card Scheme reports soil nutrient status and gives guidance for balanced fertilizer application. Its purpose includes reducing indiscriminate fertilizer use and improving soil management. It does not directly set loan amounts or expand irrigated area.

Q35. Which agricultural practices conserve water? 1. Reduced tillage. 2. Gypsum applied routinely before irrigation. 3. Retaining crop residues.

[UPSC CSE Preliminary (2017)]

• (A) 1 and 2 only
• (B) 3 only
• (C) 1 and 3 only
• (D) 1, 2 and 3

Answer: (C) 1 and 3 only

Explanation: Reduced tillage can protect soil structure and improve infiltration, while retained crop residues reduce evaporation and surface runoff. Gypsum is a soil amendment for specific problematic soils rather than a routine water-conservation technique for every field.

Q34. Which soil occupies the largest share of India’s land area?

[WBCS Preliminary (2017)]

• (A) Laterite
• (B) Red
• (C) Black
• (D) Alluvial

Answer: (D) Alluvial

Explanation: Alluvial soils are the most extensive major geographical soil group in India. They dominate the northern river plains and occur in several coastal deltas. Their productivity is important for crops including wheat, rice, sugarcane and pulses.

Q33. Which soil group is most widespread across India?

[Chhattisgarh PSC Preliminary (2017)]

• (A) Alluvial
• (B) Black
• (C) Red
• (D) Forest

Answer: (A) Alluvial

Explanation: Rivers carry and deposit large volumes of sediment across extensive Indian plains and deltas, producing alluvial soil. This group occupies more land than any other familiar geographical soil type. Its agricultural importance follows from generally favorable fertility and water availability.

Q32. Which type of soil is laid down by rivers?

[63rd BPSC Preliminary (2017)]

• (A) Red
• (B) Black
• (C) Alluvial
• (D) Laterite

Answer: (C) Alluvial

Explanation: Alluvial soil comprises sediment transported and deposited by flowing water. Active floodplains receive comparatively young khadar material, while higher terraces preserve older bhangar deposits. Such soils are extensive along the Ganga and other important river systems.

Q31. Which soil occurs largely in Muzaffarpur, Darbhanga and Champaran districts?

[63rd BPSC Preliminary (2017)]

• (A) Black
• (B) New alluvium
• (C) Old alluvium
• (D) Red

Answer: (B) New alluvium

Explanation: Northern Bihar districts receive sediment from Himalayan-fed rivers such as the Gandak and Bagmati. These deposits include relatively new alluvium that can be renewed by flooding. The soils support important crops including rice, wheat and sugarcane.

Q30. Which sequence correctly ranks water retention by soil-particle type?

[UP Review Officer/Assistant Review Officer Preliminary (2017)]

• (A) Clay, then silt, then sand
• (B) Clay, then sand, then silt
• (C) Sand, then silt, then clay
• (D) Silt, then sand, then clay

Answer: (A) Clay, then silt, then sand

Explanation: Clay has tiny particles and abundant surface area, resulting in high total water retention. Silt usually retains less and sand drains most readily. Water held too tightly by clay may not all be accessible to roots.

Q29. Assertion: Clay holds the most water. Reason: Clay has very large pore spaces. Which evaluation is correct?

[UP Review Officer/Assistant Review Officer Preliminary (2017)]

• (A) Both true and reason explains
• (B) Both true but no explanation
• (C) Assertion true, reason false
• (D) Assertion false, reason true

Answer: (C) Assertion true, reason false

Explanation: Clay retains substantial water mainly because of small particles, high surface area and tiny pore spaces, not large pores. The assertion about water storage is correct, while the reason reverses the actual pore-size relationship.

Q28. Which state among these has the greatest total area of salt-affected soil?

[UPPCS Mains (2017)]

• (A) Tamil Nadu
• (B) Rajasthan
• (C) Gujarat
• (D) Andhra Pradesh

Answer: (C) Gujarat

Explanation: Gujarat has extensive inland and coastal salt-affected lands, including saline soils associated with arid conditions and marine influences. Salinity impairs crop establishment and nutrient uptake. Reclamation varies with drainage, water quality and whether sodium or soluble salts dominate.

Q27. Which alternative name refers to black cotton soil?

[UP Review Officer/Assistant Review Officer Mains (2016)]

• (A) Bhangar
• (B) Khadar
• (C) Bhur
• (D) Regur

Answer: (D) Regur

Explanation: Regur is the name used for black cotton soil, especially in the Deccan region. Its clayey texture enables strong moisture retention and causes shrinking cracks in dry weather. Bhangar and khadar instead refer to older and newer alluvial soils.

Q26. Which soil-particle class commonly has a diameter less than 0.002 millimetre?

[UP Review Officer/Assistant Review Officer Preliminary (2016)]

• (A) Clay
• (B) Silt
• (C) Fine sand
• (D) Gravel

Answer: (A) Clay

Explanation: Clay particles are the finest mineral size class, generally smaller than 0.002 mm. Silt and sand consist of progressively larger particles. The very small clay size contributes to high surface area, water adsorption and certain swelling behaviors.

Q25. Which of these soil groups is typically considered the most productive across India?

[UP Review Officer/Assistant Review Officer Preliminary (2014)]

• (A) Red
• (B) Black
• (C) Alluvial
• (D) Calcareous

Answer: (C) Alluvial

Explanation: River-borne alluvial soils support major crop-producing plains and deltas. Their widespread distribution, generally useful texture and nutrient supply make them exceptionally important for Indian agriculture. Productivity still depends on irrigation, crop management and local soil chemistry.

Q24. India’s soil erosion is associated with which listed factors? 1. Terrace farming. 2. Deforestation. 3. Tropical climate by itself.

[UPSC CSE Preliminary (2014)]

• (A) 1 and 2 only
• (B) 2 only
• (C) 1 and 3 only
• (D) 1, 2 and 3

Answer: (B) 2 only

Explanation: Deforestation removes protective plant cover and root networks, accelerating runoff and topsoil loss. Terrace farming is normally employed to reduce erosion on slopes. A tropical climate alone is not sufficient to identify an erosion-inducing practice.

Q23. Which statements about Indian laterite soils are correct? 1. They are usually red. 2. They are rich in nitrogen and potash. 3. They dominate Rajasthan and Uttar Pradesh. 4. Cashew and tapioca grow on them.

[UPSC CSE Preliminary (2013)]

• (A) 1, 2 and 3
• (B) 2, 3 and 4
• (C) 1 and 4
• (D) 2 and 3 only

Answer: (C) 1 and 4

Explanation: Laterite soils commonly appear red because iron oxides accumulate after intense leaching. They develop chiefly in warm, humid regions rather than the arid northwest. Though generally nutrient-poor, suitable sites can support cashew and tapioca cultivation.

Q22. Which activities add nitrogen to soil? 1. Animal urea excretion. 2. Coal combustion. 3. Death and decomposition of vegetation.

[UPSC CSE Preliminary (2013)]

• (A) 1 only
• (B) 2 and 3 only
• (C) 1 and 3 only
• (D) 1, 2 and 3

Answer: (C) 1 and 3 only

Explanation: Animal waste and decomposing plants return nitrogen-containing compounds to the soil, where microbes convert them into different nutrient forms. Coal burning is not ordinarily considered a direct agricultural nitrogen-input process in this question.

Q21. Which state was identified as having the largest area of saline soil among the options?

[UPPCS Mains (2012)]

• (A) Uttar Pradesh
• (B) Haryana
• (C) Gujarat
• (D) Maharashtra

Answer: (C) Gujarat

Explanation: Gujarat has extensive saline lands, reflecting arid climate, coastal influence and drainage conditions. Salt accumulation restricts plant water uptake and can lower yields. The question concerns saline soil specifically, which is distinguished from sodic or alkaline soil.

Q20. What effect can salinisation have when irrigation water evaporates and leaves salts in soil?

[UPSC CSE Preliminary (2011)]

• (A) It sharply increases crop yields
• (B) It can make some soils impermeable
• (C) It necessarily raises groundwater
• (D) It always fills soil pores with water

Answer: (B) It can make some soils impermeable

Explanation: Evaporating irrigation water can leave salts that accumulate in the root zone. In some affected soils, structural deterioration reduces water movement and infiltration. Salinisation also creates osmotic stress, making it difficult for crops to take up water.

Q19. Which soil texture contains particles of sand, silt and clay together?

[53rd–55th BPSC Preliminary (2011)]

• (A) Sand alone
• (B) Clay alone
• (C) Silt alone
• (D) Loam

Answer: (D) Loam

Explanation: Loam combines sand, silt and clay in proportions offering a useful balance between drainage and water storage. Sand contributes coarse pores, silt adds intermediate particles and clay increases moisture and nutrient retention. Exact proportions vary among loam subclasses.

Q18. Among clay, silt, sand and loam, which material was chosen as storing the most water?

[53rd–55th BPSC Preliminary (2011)]

• (A) Clay
• (B) Silt
• (C) Sand
• (D) Loam

Answer: (A) Clay

Explanation: Clay has minute particles and a large surface area, allowing substantial water adsorption. It commonly holds more total water than coarse sand. The distinction between total retained water and plant-available water remains important in practical soil science.

Q17. Which substance is mainly responsible for the red colour of soil seen in parts of India?

[UPSC CSE Preliminary (2010)]

• (A) Magnesium
• (B) Humus
• (C) Ferric oxides
• (D) Phosphates

Answer: (C) Ferric oxides

Explanation: Ferric iron compounds form when iron-bearing minerals oxidize during weathering. They produce reddish hues in soils derived from crystalline rocks across portions of peninsular India. Humus generally darkens soil, whereas magnesium and phosphate do not explain the characteristic red shade.

Q16. Which combination was accepted for soil conservation? 1. Crop rotation. 2. Sand fences. 3. Terracing. 4. Windbreaks.

[UPSC CSE Preliminary (2010)]

• (A) 1, 2 and 3
• (B) 2 and 4 only
• (C) 1, 3 and 4
• (D) 1, 2, 3 and 4

Answer: (C) 1, 3 and 4

Explanation: The published examination key accepts crop rotation, terracing and windbreaks for soil conservation. These practices maintain cover, slow surface runoff or reduce wind erosion. Sand fences may have specialised uses, but were not included in the accepted combination.

Q15. Crop rotation is primarily important for which agricultural purpose?

[Uttarakhand PSC Preliminary (2010)]

• (A) Increasing plant protein automatically
• (B) Obtaining unrelated crops only
• (C) Maintaining soil fertility
• (D) Eliminating all irrigation needs

Answer: (C) Maintaining soil fertility

Explanation: Rotating crops changes nutrient demand and can include legumes that contribute biologically fixed nitrogen. The practice also helps manage pests and soil structure. Continuous cultivation of a single crop tends to create imbalanced nutrient withdrawal over time.

Q14. Which Indian soil is popularly described as self-ploughing?

[UP Lower Subordinate Preliminary (2009)]

• (A) Alluvial
• (B) Lateritic
• (C) Black cotton soil
• (D) Desert

Answer: (C) Black cotton soil

Explanation: Expansive clays in black regur soil swell when moist and shrink during drying. This creates deep cracks that naturally loosen and aerate the ground. The distinctive self-ploughing behavior is associated with the basaltic Deccan black-soil region.

Q13. Which district of Madhya Pradesh is especially known for severe soil erosion?

[MPPSC Preliminary (2008)]

• (A) Jabalpur
• (B) Bhopal
• (C) Morena
• (D) Khandwa

Answer: (C) Morena

Explanation: Morena lies within the Chambal ravine region, where concentrated runoff cuts deep gullies into susceptible material. The development of ravines removes productive topsoil and fragments farmland. Vegetation protection and watershed management are important conservation responses.

Q12. Which state was identified as having the largest alkali-soil area?

[UPPCS Mains (2007)]

• (A) Gujarat
• (B) Haryana
• (C) Punjab
• (D) Uttar Pradesh

Answer: (D) Uttar Pradesh

Explanation: Uttar Pradesh has extensive alkali or sodic soil affected by exchangeable sodium and high pH. This condition is different from simple soluble-salt salinity. Gypsum, drainage and water management are commonly used to reclaim suitable sodic fields.

Q11. Assertion: Andhra Pradesh had a smaller net-sown-area share than West Bengal. Reason: Most of Andhra Pradesh has laterite soil. Which choice is correct?

[UPSC CSE Preliminary (2006)]

• (A) Both true and reason explains
• (B) Both true but unrelated
• (C) Assertion true, reason false
• (D) Assertion false, reason true

Answer: (C) Assertion true, reason false

Explanation: The exam’s assertion about relative net-sown-area shares was considered true, but Andhra Pradesh is not predominantly lateritic. It has extensive red and other soils. Hence soil-type generalisation cannot explain the agricultural land-share difference asserted.

Q10. Which state listed is associated with laterite soils?

[UP Urban Development Authority / Lucknow Development Authority Preliminary (2006)]

• (A) Uttar Pradesh
• (B) Himachal Pradesh
• (C) Punjab
• (D) Maharashtra

Answer: (D) Maharashtra

Explanation: Laterite develops in humid uplands that experience intense tropical leaching, including parts of Maharashtra’s western highlands. The other options are better known for extensive alluvial or mountain soils. Laterite is relatively low in nutrients despite its iron-rich composition.

Q9. Which soil group occupies the largest area in India?

[MPPSC Preliminary (2006)]

• (A) Red
• (B) Black
• (C) Sandy
• (D) Alluvial

Answer: (D) Alluvial

Explanation: Alluvial soil is widespread across the major northern river plains and several peninsular deltas. Rivers deposit its sand, silt and clay fractions. This broad distribution exceeds that of black, red and laterite soils under standard geographical classification.

Q8. Which soil amendment is generally applied to make acidic soil more suitable for crops?

[MPPSC Preliminary (2006)]

• (A) Lime
• (B) Gypsum
• (C) Coal ash
• (D) Common salt

Answer: (A) Lime

Explanation: Lime neutralises excess soil acidity and can raise pH toward conditions favorable for many crops. Gypsum is more strongly associated with sodic-soil reclamation. Appropriate application depends on laboratory assessment, since over-liming can reduce micronutrient availability.

Q7. Which landscape is especially associated with severe ravine-type soil erosion?

[MPPSC Preliminary (2006)]

• (A) Malwa Plateau
• (B) Terai of Uttar Pradesh
• (C) Andhra coast
• (D) Chambal Valley

Answer: (D) Chambal Valley

Explanation: The Chambal Valley is famous for deep, dissected gullies and ravines resulting from prolonged concentrated runoff. These features destroy or divide agricultural land. Erosion control uses vegetative cover, catchment management and protection of vulnerable drainage lines.

Q6. In which region is soil erosion particularly critical?

[UPPCS Preliminary (2004)]

• (A) Malwa Plateau
• (B) Shivalik foothills
• (C) Dandakaranya
• (D) Meghalaya Plateau

Answer: (B) Shivalik foothills

Explanation: The fragile Shivalik foothills have unconsolidated sediments, steep slopes and seasonally intense rainfall. Together with vegetation removal they encourage rapid runoff and erosion. Soil-conservation strategies include slope stabilization, afforestation and careful land use.

Q5. Which listed region is most strongly affected by ravine and soil erosion?

[UP Lower Subordinate Preliminary (2004)]

• (A) Malwa Plateau
• (B) Terai region
• (C) Andhra coast
• (D) Chambal Valley

Answer: (D) Chambal Valley

Explanation: Chambal’s ravine landscape is a classic Indian example of severe gully erosion. Flowing water incises channels into susceptible soils, progressively cutting fields into deeply dissected terrain. Watershed management and restoration of protective vegetation help limit further degradation.

Q4. Which micronutrient is especially widely deficient in Indian agricultural soils?

[UPPCS Special Mains (2004)]

• (A) Copper
• (B) Iron
• (C) Manganese
• (D) Zinc

Answer: (D) Zinc

Explanation: Zinc deficiency is widespread in cultivated soils of India and can reduce plant growth and crop yields. Soil pH, excessive phosphorus and low available zinc influence the problem. Corrective application should follow soil and crop assessment.

Q3. Which soil texture among the given examples has the least capacity to retain water?

[Uttarakhand PSC Preliminary (2003)]

• (A) Alluvial sand
• (B) Loamy sand
• (C) Clayey loam
• (D) Loam

Answer: (A) Alluvial sand

Explanation: Sandy deposits have large grains and interconnected pores through which water drains readily. They therefore retain less water than loam or clay-rich soils. Organic inputs and careful irrigation scheduling can help improve moisture availability in sandy fields.

Q2. Which soil reaction best suits tea cultivation?

[UPPCS Preliminary (2002)]

• (A) Acidic
• (B) Strongly alkaline
• (C) Neutral saline
• (D) Black regur as such

Answer: (A) Acidic

Explanation: Tea generally thrives in well-drained, moderately acidic soils under humid conditions. Strong alkalinity can impair nutrient uptake, while waterlogging damages roots. Tea estates are commonly located on suitable hill slopes with adequate rainfall and controlled drainage.

Q1. Which statement about Indian physical geography is correct?

[UPSC CSE Preliminary (2002)]

• (A) More than one-third of India necessarily receives above 750 mm rainfall
• (B) Wells are everywhere the dominant irrigation source
• (C) Alluvial soil predominates in the Northern Plains
• (D) Mountains occupy exactly thirty percent of India

Answer: (C) Alluvial soil predominates in the Northern Plains

Explanation: Northern India’s major river systems deposited thick layers of sand, silt and clay across the vast plains. This alluvium is the region’s dominant soil. The alternative claims are not accepted in the original multiple-choice context.