Plain 23264 226007692 2008-07-16T12:29:13Z 122.53.87.217 [[Image:Cryon 5.JPG|thumb|250px|A small mirage on the road, Western plains, NSW]] In [[geography]], a '''plain''' is an area of [[landscape|land]] with relatively low relief — meaning that it is flat. [[Prairie]]s and [[steppe]]s are types of plains, and the [[archetype]] for a plain is often thought of as a [[grassland]], but plains in their natural state may also be covered in [[shrubland]]s, [[woodland]] and [[forest]], or vegetation may be absent in the case of sandy or stony plains in [[hot desert]]s. Types of [[flatland]]s for which the term is not generally used include those covered entirely and permanently by [[swamp]]s, [[marsh]]es, [[playa]]s, or [[ice sheet]]s. Plains occur as [[lowland]]s and at the bottoms of [[valley]]s but also on [[plateau]]s at high [[elevation]]s. They may have been formed from flowing [[lava]], deposited by water, ice or wind, or formed by [[erosion]] by these agents from hills and mountains. Plains in many areas are important for [[agriculture]], because where the soils were deposited as [[sediment]]s they may be deep and [[fertile]], and the flatness facilitates mechanisation of crop production; or because they support grasslands which provide good grazing for [[livestock]]. ===Types of terrestrial plains=== [[Image:Lightning Ridge2.JPG|thumb|250px|Part of the plain that surrounds [[Lightning Ridge]], NSW]] *[[Coastal plain]], an area of low-lying land adjacent to a sea coast; the term is used especially where they contrast with hills, mountains or plateaux further inland. *'''Fluvial plains''' are formed by rivers and streams, and may be one of these overlapping types: **[[Flood plain]], adjacent to a stream, river, lake or wetland that experiences occasional or periodic [[flooding]]. **[[Alluvial plain]], formed over a long period of time by a [[river]] depositing sediment on its floodplain or bed which becomes [[alluvial]] soil. The difference between a floodplain and an alluvial plain is that the floodplain represents the area experiencing flooding fairly regularly in the present or recently, whereas an alluvial plain includes areas where the floodplain is now and used to be, or areas which only experience flooding a few times a century. **[[Scroll plain]], a plain through which a river [[meander]]s with a very low gradient.<!--NOTE this may be merged with floodplain or alluvial plain in the future.--> *[[Lacustrine plain]], a plain that originally formed in a [[lacustrine]] environment, that is, as the bed of a [[lake]]. *[[Lava plain]], formed by sheets of flowing [[lava]]. *[[Till plain]], a plain of [[glacial till]] that forms when a sheet of [[ice]] becomes detached from the main body of a [[glacier]] and melts in place depositing the [[sediment]]s it carried. ===Other types of plain=== The term may also be used for flat areas of the [[ocean]] floor or for flat areas on moons and planets. *[[Abyssal plain]], a flat or very gently sloping area of the deep ocean basin floor. ===Notes and references=== <references /> {{Unreferenced|date=April 2007}} {{Sectstub|date=May 2008}} ==See also== {{Wiktionary}} *[[Field (agriculture)|Field]] *[[Flooded grasslands and savannas]] *[[Flood-meadow]] *[[Grassland]] *[[Liverpool Plains]] *[[Machair]] *[[Meadow]] *[[Pasture]] *[[Plateau]] *[[Prairie]] *[[Rangeland]] *[[Savanna]] *[[Steppe]] *[[Water-meadow]] *[[Wet meadow]] *[[Veld]] <noinclude> [[Category:Plains| ]] [[ar:سهل]] [[gn:Ñu]] [[ay:Pallalla]] [[be-x-old:Раўніна]] [[br:Kompezenn]] [[bg:Равнина (география)]] [[ca:Plana]] [[de:Ebene (Geographie)]] [[es:Llanura]] [[eo:Ebenaĵo]] [[eu:Ordoki]] [[fa:جلگه]] [[fr:Plaine]] [[ko:평야]] [[it:Pianura]] [[he:מישור (גאוגרפיה)]] [[lv:Līdzenums]] [[lt:Lyguma]] [[nl:Vlakte]] [[ja:平野]] [[nn:Slette]] [[pl:Równina]] [[ru:Равнина]] [[scn:Chianu]] [[fi:Tasanko]] [[sv:Slätt]] [[te:మైదానం]] [[tr:Ova]] [[uk:Рівнина]] [[zh:平原]]