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.
