Q31. The upward movement of groundwater carrying dissolved salts to the surface layer, which subsequently evaporates leaving a white saline crust, is a result of:
Soils of Rajasthan: RAS Prelims MCQs
37 RAS Prelims MCQs on the soils of Rajasthan cover the soil types, their districts and properties. Desert sandy soils, alluvial soils of the eastern plains, black soils of Kota and Bundi, the Bhangar and Khadar deposits, the Entisols of USDA taxonomy and the problem of salinity are asked as facts and causes.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 31–37 of 37 questions
Q32. Match the physiological features of Rajasthan (List I) with their dominant soil classes (List II):
| Physiological Features | Soil Classes |
|---|---|
| A. Aravalli Hills | i. Alfisols |
| B. Hadoti Plateau | ii. Aridisols |
| C. Eastern River Plains | iii. Vertisols |
| D. Western Sandy Plains | iv. Lithosols/Inceptisols |
Explanation
Rajasthan’s physiological features are dominated by specific soil classes.
Q33. Which of the following statements regarding the Lithosols of the Aravalli region is incorrect?
Explanation
The Lithosols of the Aravalli region are characterized by a very shallow soil depth and a high concentration of gravel and unweathered rock fragments. They are highly susceptible to runoff and water erosion due to their steep locations. Consequently, they possess very poor water-holding capacity and lack deep organic topsoil, making them unsuitable for most forms of intensive and commercial agriculture.
Q34. A forest department official planning an afforestation drive on the Lithosols of the Aravalli slopes must select plant species primarily adapted to which of the following constraints?
Explanation
Afforestation on the Lithosols of the Aravalli slopes requires selecting species that can thrive despite significant constraints. These soils offer very shallow rooting depth and extremely low moisture retention due to their stony and skeletal nature. Plants must be hardy enough to survive in a thin soil layer where water drains away quickly and nutrient availability is limited by minimal weathering.
Q35. Brown soils, known for supporting significant Kharif and Rabi agriculture in the semi-arid transitional zones, are characteristically found in the basin of which river?
Explanation
Brown soils are characteristically found in the semi-arid transitional zones of Rajasthan, particularly within the Banas River basin. These soils support significant agriculture for both Kharif and Rabi seasons. They are more fertile and have better moisture retention than the desert sands of the west, making them vital for the agricultural economy of the central and eastern parts of the state.
Q36. Consider the following features of reddish-brown soils in Rajasthan:
I. They are predominantly found in Jalore, Pali, and Nagaur.
II. They have a sandy loam to clay loam texture.
III. They are virtually devoid of calcium carbonate.
IV. Their nitrogen content is naturally very high.
Which combination of the above statements is incorrect?
I. They are predominantly found in Jalore, Pali, and Nagaur.
II. They have a sandy loam to clay loam texture.
III. They are virtually devoid of calcium carbonate.
IV. Their nitrogen content is naturally very high.
Which combination of the above statements is incorrect?
Explanation
Reddish-brown soils are common in districts like Jalore, Pali, and Nagaur, featuring textures ranging from sandy loam to clay loam. However, it is incorrect to say they are devoid of calcium carbonate or have naturally high nitrogen content. In reality, these soils often contain some lime and, like most soils in Rajasthan, are typically deficient in nitrogen and organic matter.
Q37. In which of the following sets of districts is the ‘Brown Sandy’ soil predominantly distributed?
Explanation
Brown sandy soils are predominantly distributed across the semi-arid regions of Rajasthan. These soils are most commonly found in a belt including districts like Jodhpur, Pali, Nagaur, and Sikar. They represent a transition between the extremely arid desert sands to the west and the more fertile alluvial or black soils found in the eastern and south-eastern parts of the state.Answer key for these questions
| Q | Correct answer |
|---|---|
| 31 | (c) Capillary action |
| 32 | (a) A-iv, B-iii, C-i, D-ii |
| 33 | (d) They have excellent water-holding capacity and deep organic topsoil. |
| 34 | (a) Shallow rooting depth and low moisture retention |
| 35 | (b) Banas |
| 36 | (b) III and IV only |
| 37 | (a) Jodhpur, Pali, Nagaur, and Sikar |
Key facts from Soils of Rajasthan
- In the arid west, extreme climate is the dominant factor in soil formation.
- Alluvial soils are most extensive in Bharatpur, Dholpur and Tonk; older alluvium is called Bhangar.
- Desert sandy soils have sandy and loamy sand textures with weak profile development.
- Black soils of Kota and Bundi shrink and swell because of the mineral montmorillonite; deep black soil is found in Jhalawar.
- Entisols occupy the largest area under the USDA soil taxonomy.
- Salts rise to the surface by capillary action and cause salinity.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Soils of Rajasthan?
This page has 37 practice MCQs on Soils of Rajasthan (Rajasthan Geography). Each has the correct answer, and most have an explanation.
Which soil occupies the largest area in Rajasthan?
The Entisols, according to the USDA soil taxonomy. They are young soils with little profile development, typical of sandy desert areas, and they cover the arid west of the State from Jaisalmer and Barmer to Bikaner.
Why do black soils crack and swell?
Because they contain the clay mineral montmorillonite, which expands when wet and shrinks when dry. This gives the black soils of Kota and Bundi their deep cracks in summer.
What is Bhangar?
The older alluvial deposits of the eastern plains, found on higher terraces above the flood level. The newer flood-plain deposits are called Khadar, and the two are used to describe the alluvial plains of north India.