Doab
Doab is a term used in South Asia for the tract of land lying between two confluent rivers. It is similar to an interfluve. In the Oxford Hindi-English Dictionary, R. S. McGregor refers to its Persian origin in defining it as do-āb "a region lying between and reaching to the confluence of two rivers."
Khadir, bangar, barani, nali and bagar
Since North India and Pakistan are coursed by a multiplicity of Himalayan rivers that divide the plains into doabs, 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 or bangar for many centuries, and different agricultural tax rates applied based on a tiered land-productivity scale.
The Doab
The Doab designates the flat alluvial tract between the Ganges and Yamuna rivers extending from the Sivalik Hills to the two rivers' confluence at Prayagraj. It is also called as Ganges-Yamuna Doab or Ganga Doab. The region has an area of about 23,360 square miles ; it is approximately in length and in width.The British Raj] divided the Doab into three administrative districts, viz., Upper Doab, Middle Doab and Lower Doab.
Currently the following states and districts form part of The Doab:
Upper Doab
Main article : Upper Doab- Uttarakhand:
- Uttar Pradesh:
- '''Delhi'''
Central or Middle Doab