View of a canal in the lower Bari Doab of the Punjab Doabs
Doab (from Persian d?, "two" + ?b, "water" or "river") is a term used in the Indian subcontinent for the "tongue," or water-rich tract of land lying between two converging, or confluent, rivers. It is similar to an interfluve. In the Oxford Hindi-English Dictionary, R. S. McGregor defines it as "a region lying between and reaching to the confluence of two rivers (esp. that between the Ganges and Yamuna)."
Since North India and Pakistan are coursed by a multiplicity of Himalayan rivers that divide the plains into doabs (i.e. regions between two rivers), the Indo-Gangetic plains consist of alternating regions of river, khadir and bangar. The regions of the doabs near the rivers consist of low-lying, floodplains, but usually very fertile khadir and the higher-lying land away from the rivers consist of bangar, less prone to flooding but also less fertile on average.
Khadir is also called Nali or Naili, specially in northern Haryana the fertile prairie tract between the Ghaggar river and the southern limits of the Saraswati channel depression in that gets flooded during the rains.
Within bangar area, the Barani is any low rain area where the rain-fed dry farming is practiced, which nowadays are dependent on the tubewells for irrigation.Bagar tract, an example of barani land, is the dry sandy tract of land on the border of Rajasthan state adjoining the states of Haryana and Punjab.Nahri is any canal-irrigated land, for example, the Rangoi tract which is an area irrigated by the Rangoi channel/canal made for the purpose of carrying flood waters of Ghagghar river to dry areas.
Historically, villages in the doabs have been officially classified as khadir, khadir-bangar (i.e. mixed) or bangar for many centuries and different agricultural tax rates applied based on a tiered land-productivity scale.
The Yamuna-Ganga Doab or Uttar Pradesh Doab designates the flat alluvial tract between the Ganges and Yamuna rivers extending from the Sivalik Hills to the two rivers' confluence at Allahabad. The region has an area of about 23,360 square miles (60,500 square km); it is approximately 500 miles (805 km) in length and 60 miles (97 km) in width.
The region of the Doab figures prominently in the history and myths of Vedic period. The British raj divided the Doab into three administrative districts, viz., Upper Doab (Meerut), Middle Doab (Agra) and Lower Doab (Allahabad).
Currently the following states and districts form part of the Ganga Doab:
Each of the tracts of land lying between the confluent rivers of the Punjab region of Pakistan and India has a distinct name, said to have been coined by Raja Todar Mal, a minister of the Mughal emperor Akbar. The names (except for 'Sindh Sagar') are a combination of the first letters, in the Persian alphabet, of the names of the rivers that bound the Doab. For example, Jech = 'Je'(Jhelum) + 'Ch'(Chenab). The names are (from west to east):
... khaddar soils. Away from the river, toward the middle of the doabs, older alluvial soils (called bangar) are widely distributed ...
... The rates here applied were the same as those applied in the Bangar and Khadar circles and the same comparisons hold good ...
... The Khadar-Bangar chak lies along the river; 37 villages are purely Khadar and 39 partly Khadar partly Bangar. The villages nearest the river are subject to inundations, but where the water runs off in time, the natural fertility of the ...