RAS question
Saline/Alkaline soils in Rajasthan are concentrated around which of the following lake regions?
Correct answer: (A) Sambhar, Didwana, and Pachpadra.
In Rajasthan, saline and alkaline soils are concentrated around the salt-lake depressions of Sambhar, Didwana and Pachpadra.
Explanation
Saline and alkaline soils in Rajasthan are linked to natural saline depressions rather than to ordinary freshwater lake basins. The Rajasthan Forest Department manual states that saline-sodic soils are common in natural depressions such as Pachpadra, Sambhar and Didwana, and separately notes that Sambhar and Pachpadra produce sodium chloride from salt water while Didwana produces sodium sulphate. That directly explains why the Sambhar-Didwana-Pachpadra group is the correct lake region: these basins leave salt deposits that raise surrounding soil salinity. The local terms are Usar, Kalar and Reh, and gypsum, or calcium sulphate, is used in reclamation because calcium replaces sodium and improves soil structure.
Why the other options are wrong
- (B) Pushkar, Siliserh and Rajsamand are freshwater lakes, so this group is not the salt-lake depression belt associated with saline deposits and soil salinisation.
- (C) Jaisamand, Meja and Nakki are reservoir or freshwater lakes, not saline lakes, so their surroundings are not the standard saline-soil concentration zone.
- (D) Fateh Sagar, Udai Sagar and Pichhola are freshwater Udaipur lakes and are not associated with the salt-lake process that forms saline or alkaline soils.
Concept
This tests Rajasthan physical geography through the link between lake basins, salt deposition and soil types. It recurs in RAS because saline-sodic soils, local soil names and reclamation methods are standard Rajasthan geography facts.