ICAR Soil Classification Applied to Rajasthan

The Indian Council of Agricultural Research (ICAR) adopted the USDA Soil Taxonomy system, which classifies soils into 12 Orders globally. Rajasthan's soils map onto 8 of these 12 orders:

USDA/ICAR Order	Common Name	Rajasthan Occurrence	Approximate Area
Aridisols	Arid soils with calcic/gypsic horizons	Western Rajasthan desert; Bikaner, Jaisalmer, Barmer	~40% of state
Entisols	Weakly developed/young soils	Active sand dunes; riverine new alluvium	~20% of state
Inceptisols	Slightly developed soils	River valleys (Chambal, Banas), Aravalli slopes	~15% of state
Alfisols	Moderate leaching, clay accumulation	Eastern Rajasthan alluvial plains, red soil areas	~10% of state
Vertisols	Black/regur, swelling clay	Kota, Bundi, Jhalawar, Baran (Hadoti plateau)	~5% of state
Mollisols	Dark, base-rich grassland soils	Northern alluvial plains (Ganganagar)	~2% of state
Oxisols	Highly weathered, iron-rich	Mt. Abu zone, southern Sirohi	< 1% of state
Ultisols	Leached, low-base status	Dungarpur, Banswara (lateritic/red deep soils)	< 1% of state

Source: ICAR–National Bureau of Soil Survey and Land Use Planning (NBSS&LUP), Nagpur — Soil Map of Rajasthan; Rajasthan Agricultural Statistics 2023-24

Note for exam use: The colloquial names (desert, alluvial, black, red, laterite) match actual RPSC question phrasing better than the ICAR orders. However, knowing the order names signals higher understanding — include in 10-mark answers where word count permits.

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