


Irrigation Research Needs in the USA Mid-South and Southeast, Humid and Sub-Humid Regions


Citation:  5th National Decennial Irrigation Conference Proceedings, 5-8 December 2010, Phoenix Convention Center, Phoenix, Arizona USA  IRR10-8679.(doi:10.13031/2013.35852)
Authors:   Earl D Vories, Steven R Evett
Keywords:   Humid regions irrigation, surface water supply, aquifer depletion, irrigation management, water quality, water quantity, watersheds

Irrigated area in the Mid-South and Southeast United States continues to increase greatly in response to economic imperatives (risk avoidance) and recurring short- and long-term drought conditions and now totals 4 million ha even though mean annual precipitation in those regions exceeds 1 m. Most new irrigation is supplied from groundwater, meaning that the water is pressurized and possibilities for improved irrigation efficiencies exist, but increased groundwater use has also caused aquifer declines. With irrigation comes a more stable production environment, which encourages increased plant densities and associated fertilizer and pesticide inputs that must be appropriately managed to prevent ground and surface water pollution. Because of commonly low available water holding capacities and root-limiting layers at shallow depths in many soils in these regions, irrigation management is difficult and appropriate methods are not well identified. Water quality and water use efficiency impacts under irrigation are also poorly understood, but comprehension is necessary if conversion from groundwater to surface water supplies is to be justified. At the same time that irrigation has rapidly increased, research and extension personnel in the region focusing on irrigation have declined in number. Furthermore, the ARS irrigation research effort has not sufficiently increased in response to the new challenges for irrigation to provide food and fiber for an expanding population. A combined state and federal response to these challenges is needed to provide appropriate and effective problem solutions that ensure efficient water use and high crop water productivity while protecting water supplies and the environment.

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