Saline and alkaline soils in different parts of India are locally known as Thur, Reh, Kallar and:

Saline and alkaline soils are known by different local names in India: Reh and Usar in Uttar Pradesh, Kallar in Punjab and Haryana, and Thur in parts of Punjab and Rajasthan.

What are saline and alkaline soils?

Saline soils contain a high concentration of soluble salts, such as chlorides and sulphates of sodium, calcium and magnesium. They often show a white crust of salt on the surface (sometimes called "white alkali").

Alkaline (sodic) soils contain a high proportion of exchangeable sodium and often sodium carbonate. They have a high pH (above 8.5), poor structure and low permeability. The organic matter may dissolve and give a black colour ("black alkali").

Both types are generally infertile and unsuitable for most crops unless reclaimed.

Where they are found:

• Dry regions of Gujarat, Punjab, Haryana and Uttar Pradesh.
• Waterlogged and canal-irrigated areas, especially in Punjab, Haryana and western Uttar Pradesh.
• Coastal areas and deltas, such as the Rann of Kutch, the Sundarbans and the deltas of the eastern coast, where sea water enters the land.

Causes:

• Poor drainage, rising groundwater and over-irrigation, especially in canal command areas.
• Capillary action bringing salts to the surface in hot, dry climates.

Reclamation:

• Applying gypsum to alkaline soils, which replaces sodium with calcium; pyrite and press mud are also used.
• Providing surface and sub-surface drainage, and leaching the salts with good-quality water.
• Growing salt-tolerant crops (barley, cotton, mustard and some rice varieties) and green manure crops such as dhaincha.

Institutions:

The Central Soil Salinity Research Institute (CSSRI) at Karnal, Haryana, has developed technologies to reclaim lakhs of hectares of usar land in Uttar Pradesh, Haryana and Punjab.

Other local soil terms:

• Bhur: sandy, wind-deposited soil found in the upper Ganga-Yamuna doab and parts of western Uttar Pradesh.
• Regur: the local name of black soil.
• Kankar: nodules of calcium carbonate found in some soils.

Why not the other options?

• ✗Bhur refers to sandy soil, not saline soil.
• ✗Regur is black cotton soil.
• ✗Kankar refers to lime nodules, not a type of saline soil.