Identify the type of soil on the basis of given characteristics : 1. They contain a large proportion of sodium, potassium and magnesium, and thus, they are infertile. 2. Their structure ranges from sandy to loamy. 3. They are more widespread in western Gujarat, deltas of the eastern coast and in Sunderban areas of West Bengal.

The correct answer is D, Saline soil. All three features listed, excess salts of sodium, potassium and magnesium, a sandy to loamy texture and their spread in western Gujarat, the eastern deltas and the Sundarbans, describe saline soils. Saline soils, also called usara soils, form where poor drainage or seawater lets salts build up in the upper layer, and they also occur in dry areas and in canal-irrigated tracts where waterlogging has raised salts to the surface. They lack nitrogen and calcium, so they are largely infertile; adding gypsum helps to reclaim them. Option A is wrong because peaty soils are rich in humus and organic matter and are found in heavy-rainfall areas such as Kerala and the coastal Sundarbans swamps, not defined by salts. Option B is wrong because laterite soils form under heavy rainfall by leaching and are rich in iron and aluminium. Option C is wrong because arid soils are sandy desert soils of Rajasthan, low in humus, with salt only in some places. Exam tip: saline soil = usara or kallar, infertile, reclaimed with gypsum; Rann of Kutch and deltas.