Fertile soil deposited by rivers as they slow down and drop their sediment, the most widespread and agriculturally important soil in India, covering the northern plains and the coastal and delta regions.
- The most widespread soil type in India, covering about two-fifths of the land area, especially the Indo-Gangetic-Brahmaputra plains and the coastal and deltaic tracts.
- Transported and deposited by rivers (and to a small extent by wind and sea), so it is rich in potash, phosphoric acid, and lime, but generally poor in nitrogen and humus.
- Divided by age into bhangar (the older alluvium of higher terraces, darker, with lime nodules called kankar) and khadar (the newer, finer, lighter, more fertile alluvium of the flood plains, renewed each flood).
- Highly fertile and intensively farmed; supports wheat, rice, sugarcane, and a dense population.
- Generally fine-grained loamy to clayey; texture and fertility improve from the rough piedmont (bhabar) zone down to the deltas.
The bhangar-versus-khadar distinction, the kankar nodules, the spread over the northern plains, and the nutrient profile are recurring soils and agriculture facts.
Bhangar is the older, higher, less fertile alluvium with kankar nodules; khadar is the newer, lower, more fertile flood-plain alluvium renewed by floods. Alluvial (river-deposited, very fertile) differs from black cotton soil (basalt weathering) and laterite (leached, infertile).
River-deposited, most widespread and fertile soil of the northern plains; older bhangar (with kankar) versus newer khadar.