Type of soil is important part of Geography syllabus and UPSC Preparation. Previous Year Question (PYQ) papers are invaluable resources for aspirants preparing for competitive exams like the Union Public Service Commission (UPSC) examinations. In this article we present important PYQ on types of Soil.
PYQ on Type of Soil
Q- The black cotton soil of India has been formed due to the weathering of (2021)
(a) Brown forest soil
(b) Fissure volcanic rock
(c) Granite and schist
(d) Shale and limestone
Answer– Option B
EXPLANATION
Black soil in India is the result of the weathering of fissure volcanic rock.
The formation of black soil is influenced significantly by climatic conditions and the composition of the parent rock material. These soils are predominantly found in interior regions of Gujarat, Maharashtra, Karnataka, and Madhya Pradesh, particularly on the Deccan lava plateau and the Malwa Plateau. This distribution is due to the combination of moderate rainfall and the presence of basaltic rock beneath the surface.
Q- With reference to agricultural soils, consider the following statements : (2018)
- High content of organic matter in soil drastically reduces its water holding capacity.
- Soil does not play any role in the sulphur cycle.
- Irrigation over a period of time can contribute to the salinization of some agricultural lands.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer- Option B
EXPLANATION
Soil water-holding capacity refers to the volume of water a soil can retain for plant utilization, with soil texture and organic matter being critical factors influencing this capacity. Sulphur, one of three essential nutrients circulating among soil, vegetation, and the atmosphere, plays a vital role in biological processes, despite its primary presence in sedimentary rocks. Its release occurs through the weathering of rocks and minerals. Agricultural lands under irrigation face significant challenges from soil salinity, wherein prolonged irrigation can lead to the accumulation of salt deposits, posing risks to crop health.
Q- Which of the following statements regarding laterite soils of India are correct? (2013)
- They are generally red in colour.
- They are rich in nitrogen and potash.
- They are well-developed in Rajasthan and UP.
- Tapioca and cashew nuts grow well on these soils.
Select the correct answer using the codes given below.
(a) 1, 2 and 3
(b) 2, 3 and 4
(c) 1 and 4
(d) 2 and 3 only
Answer- Option C
EXPLANATION
Lateritic soils are primarily formed as a result of prolonged weathering under specific environmental conditions characterized by high temperatures and heavy rainfall, alternating between wet and dry periods. This weathering process, intensified by heavy rainfall, leads to leaching of lime and silica from the soil, leaving behind a soil rich in iron and aluminum oxides.
Regarding their chemical composition, laterite soils are typically rich in bauxite or ferric oxides but deficient in lime, magnesia, potash, and nitrogen. However, they may contain elevated levels of phosphate in the form of iron phosphate, especially in wetter regions where humus content may also be higher.
Geographically, laterite soils span approximately 2.48 lakh sq km and are commonly found in the summits of the Western Ghats, Eastern Ghats, Rajmahal Hills, Vindhyan, Satpuras, and Malwa Plateau, typically at elevations between 1000 to 1500 meters above sea level. Additionally, they occur in lower elevations and valleys across various regions, with notable presence in South Maharashtra and parts of Karnataka.
While laterite soils are generally infertile due to leaching, with proper manuring and irrigation, some areas are suitable for cultivating plantation crops such as tea, coffee, rubber, cinchona, coconut, and arecanut. In certain regions, these soils also support grazing grounds and scrub forests.
Q- Contour bunding is a method of soil conservation used in – (2013)
(a) desert margins, liable to strong wind action
(b) low flat plains, close to stream courses, liable to flooding
(c) scrublands, liable to spread of weed growth
(d) None of the above
Answer- Option D
In hilly regions, a technique for soil and water conservation involves constructing earthen embankments along the contour of the land. These embankments are built to closely follow the slope of the land, effectively reducing the downward flow of water.
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