Arid soils in India are characteristically developed in:

Arid (desert) soils are typical of western Rajasthan, in the Thar Desert, and are also found in parts of Haryana, Punjab and Gujarat (Kutch). They cover about 4 per cent of India's area.

How arid soils form:

• They develop in a dry climate with low rainfall (usually less than about 50 cm a year) and high temperatures.
• Because of the lack of water, chemical weathering is limited, and most of the weathering is physical (mechanical), caused by heating and cooling of rocks and wind action.
• There is very little vegetation, so the soils contain very little organic matter.
• Wind is the main agent shaping the landscape, forming sand dunes and spreading sand over large areas.

Characteristics of arid soils:

• Colour: red to brown.
• Texture: generally sandy to gravelly, with a loose structure.
• They are low in organic matter and nitrogen, and moderate in phosphate.
• They are often saline in some areas, and in places common salt is obtained by evaporating the water of salt lakes.

In the lower horizons, a hard layer of calcium carbonate nodules called kankar is often found. It forms because calcium accumulates below the surface instead of being washed out. This layer restricts the downward movement of water and the growth of roots.

Agriculture in arid soils:

• Without irrigation, only drought-hardy crops such as bajra, moth, guar, moong and some oilseeds can be grown.
• With irrigation, as in the command area of the Indira Gandhi Canal, these soils can grow wheat, mustard, cotton, groundnut and gram.

Problems:

Wind erosion, shifting sand dunes, desertification, salinity and scarcity of water.

Research and conservation:

• Water harvesting with traditional structures such as kunds and tankas helps in such areas.
• The Central Arid Zone Research Institute (CAZRI), Jodhpur, conducts research on arid lands.

Why not the other options?

• ✗The Kerala coast has laterite, alluvial and coastal sandy soils in a very wet climate.
• ✗The Brahmaputra valley has fertile alluvial soils.
• ✗The Sundarbans delta has saline, marshy and alluvial soils.