by Matt Rosenberg October 29th, 2012
Irrigation in agriculture packs a big economic punch. Although the almost 57 million acres of irrigated farmlands in the U.S. represent just 7.5 percent of all crop- and pasturelands in the nation, that good wet earth nonetheless accounts for a full 40 percent of the value of U.S. agricultural production and is on average more than three times more productive in dollar terms than dry croplands, according to a report issued last month by the Economic Research Service of the U.S. Department of Agriculture. The report, “Water Conservation in Irrigrated Agriculture: Trends and Challenges in the Face of Emerging Demands,” also notes that almost three-quarters of U.S. irrigated agriculture in is 17 Western states. The report warns that competing demands for water will mount from requirements for in-stream flows to protect water-borne species; from Native American water rights; and from an expanding energy sector. One response will need to be increased water conservation in irrigated agriculture through improvements to equipment and management practices, the report says.
Washington State ranks 10th nationally in irrigated acres of farmland. Twelve states together account for more than three-quarters of U.S. irrigated acres of harvested cropland, pasture and other lands. Among those 12 are Washington, Oregon, Idaho and Montana, which together account for 15.8 percent of U.S. irrigated acres. Three data visualizations from the USDA report follow.
U.S. irrigated acres grew from 48.8 million in 1982 to 56.5 million by 2007. Total irrigated acres grew most sharply in that time in the Northern Plains, and Delta regions, and have declined in the Pacific region.
Western U.S. crops most requiring irrigation are rice, vegetables, orchard fruits, peanuts, and sugar beets. A very small percentage of wheat croplands in Western states are irrigated.