Explanation:

- Aluminum: Not typically high in western Rajasthan soils. These soils are more saline and alkaline rather than acidic, where aluminum might be more prevalent.

- Calcium: Correct. Western Rajasthan's soils, such as desert soils, often have high calcium content. This is due to the arid conditions and evaporation, leaving calcium carbonate deposits.

- Nitrogen: Generally low in desert soils, as organic matter content is minimal due to dry conditions.

- Phosphorus: Often available in limited quantities in desert soils, not particularly high in these regions.