Submitted to: Sustainability of Irrigated Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 15, 2006
Publication Date: April 1, 2006
Citation: Howell, T.A. 2006. Challenges in increasing water use efficiency in irrigated agriculture. In: International Symposium on Water and Land Management for Sustainable Irrigated Agriculture, April 4-8, 2006, Adana, Turkey. p. 11. Interpretive Summary: Irrigation is the principal method for increasing crop yields in regions with precipitation that is inadequate or too erratic to meet the crop needs. Irrigation requires large quantities of high quality water. The purpose of this paper was to review irrigation from a world level and to discuss methods for improving the crop yield per unit of water used in irrigated agriculture. In the world, about 684 million acres are irrigated (about 15% of the cultivated land) but produce about 36% of the world’s food. Water use efficiency (WUE) is defined as the crop yield per unit of water use. Agronomy and engineering are the predominate means for enhancing WUE. But WUE can be increased by reducing losses of water to unusable water sources with degraded quality and by reallocating water to its highest use. The last item is strongly linked to societal aspects affecting water use and regulations.
Technical Abstract: Irrigated agriculture is a vital component of total agriculture and supplies many of the fruits, vegetables, and cereal foods consumed by humans; the grains fed to animals that are used as human food; and the feed to sustain animals for work in many parts of the world. World-wide irrigation was practiced on about 277 million ha in 2003 with about 48% of the world’s irrigation in India, China, and the United States. The objectives of this paper are to review irrigation worldwide in meeting our growing needs for food production, to discuss various concepts that define water use efficiency (WUE) in irrigated agriculture from both engineering and agronomic view points, and to discuss the impacts of enhanced WUE on water conservation. Scarcely one-third of our rainfall, surface water, or groundwater is used to produce plants useful to mankind. Without appropriate management, irrigated agriculture can be detrimental to the environment and can endanger sustainability. Irrigated agriculture is facing growing competition for low-cost, high-quality water. WUE in irrigated agriculture is broader in scope than most agronomic applications and must be considered on a watershed, basin, irrigation district, or catchment scale. The main pathways for enhancing WUE in irrigated agriculture are to increase the output per unit of water (engineering and agronomic management aspects), reduce losses of water to unusable sinks and reduce water degradation (environmental aspects), and reallocate water to higher priority uses (societal aspects).