Submitted to: Encyclopedia of Soil Science
Publication Type: Review Article
Publication Acceptance Date: 5/15/2002
Publication Date: 7/8/2002
Citation: FAUSEY, N.R. SUBIRRIGATION. LAL. R., EDITOR. MARCEL DEKKER, NEW YORK, NY. ENCYCLOPEDIA OF SOIL SCIENCE. 2002. P. 1276-1278.
Technical Abstract: Subirrigation is the practice of adding water to the soil by means of subsurface drains that are also used to drain water from the soil during periods when the soil is too wet. The drains may be open drains (ditches) or closed drains (drainpipes). Water may be supplied from a surface or a subsurface source and is delivered into the subsurface drains and allowed to redistribute within the soil from these subsurface drains. Control structures within the ditches or at the outlet of the closed drains are used to block the water from leaving through the outlet and thereby to establish a pressure gradient to cause water to flow from the drains into the soil. Subirrigation is only applicable to areas needing subsurface drainage and having an available adequate water supply. These areas typically have high water tables during some times of the year that can be lowered by subsurface drainage. Subirrigation depends upon being able to reestablish an elevated water table and this requires a substantial amount of water not only to raise the water table but also to meet the evapotranspiration demand of the crop in order to maintain the water table at a raised position within the soil.