Editing Irrigation (section)

=== Subirrigation ===
[[Subirrigation]] has been used for many years in field crops in areas with high [[water table]]s. It is a method of artificially raising the water table to allow the [[soil]] to be [[wikt:moisten|moistened]] from below the plants' [[root]] zone. Often those systems are located on permanent grasslands in lowlands or river valleys and combined with drainage infrastructure. A system of pumping stations, canals, weirs and gates allows it to increase or decrease the water level in a network of ditches and thereby control the water table.

Subirrigation is also used in the [[commerce|commercial]] [[greenhouse]] production, usually for [[potted plant]]s. Water is delivered from below, absorbed by upwards, and the excess collected for recycling. Typically, a solution of water and [[nutrient]]s floods a container or flows through a trough for a short period of time, 10–20 minutes, and is then pumped back into a holding [[Water tank|tank]] for reuse. Sub-irrigation in greenhouses requires fairly sophisticated, expensive equipment and management. Advantages are water and nutrient conservation, and labor savings through reduced system maintenance and [[automation]]. It is similar in principle and action to subsurface basin irrigation.

Another type of subirrigation is the self-watering container, also known as a [[sub-irrigated planter]]. This consists of a planter suspended over a reservoir with some type of wicking material such as a polyester rope. The water is drawn up the wick through capillary action.<ref>{{cite web|url=http://www.entheogen.com/forum/showthread.php?t=13076 |title=Polyester ropes natural irrigation technique |publisher=Entheogen.com |access-date=2012-06-19 |url-status=dead |archive-url=https://web.archive.org/web/20120412031536/http://www.entheogen.com/forum/showthread.php?t=13076 |archive-date=April 12, 2012 }}</ref><ref>{{cite web|url=http://www.instructables.com/id/Self-watering-recycled-plant-pot-for-growing-herbs/ |title=DIY instructions for making self-watering system using ropes |publisher=Instructables.com |date=2008-03-17 |access-date=2012-06-19}}</ref> A similar technique is the [[wicking bed]]; this too uses capillary action.