Why irrigation is used

Surface irrigation Water is distributed over and across land by gravity, no mechanical pump involved. Localized irrigation Water is distributed under low pressure, through a piped network and applied to each plant. Drip irrigation A type of localized irrigation in which drops of water are delivered at or near the root of plants. In this type of irrigation, evaporation and runoff are minimized. Sprinkler irrigation Water is distributed by overhead high-pressure sprinklers or guns from a central location in the field or from sprinklers on moving platforms.

Center pivot irrigation Water is distributed by a system of sprinklers that move on wheeled towers in a circular pattern.

This system is common in flat areas of the United States. Lateral move irrigation Water is distributed through a series of pipes, each with a wheel and a set of sprinklers, which are rotated either by hand or with a purpose-built mechanism.

The sprinklers move a certain distance across the field and then need to have the water hose reconnected for the next distance. This system tends to be less expensive but requires more labor than others. Irrigation has enhanced both the productivity and profitability of the agricultural sector. According to the Census of Agriculture, farms with some form of irrigation accounted for more than 54 percent of the total value of U.

Irrigated crop production helps to support local rural economies in many areas of the U. The Census of Agriculture reported total U. Much of the irrigated land is concentrated in the western U. Irrigation is also common in the southeastern U. Where irrigation occurs depends on regional cropping patterns, local climatic conditions as well as the availability of surface and groundwater resources.

Embed this chart Download higher resolution chart pixels by , dpi. Nebraska had the most irrigated land among all U. States, with 8. The prevalence of irrigated acreage in Nebraska relates to the abundance of groundwater resources as much of the state overlies the High Plains Ogallala aquifer. California ranked second, with 7. The twenty highest-ranked States in irrigated acreage accounted for about 90 percent of all irrigated land in The importance of irrigation for U.

Powered by. To irrigate is to water crop s by bringing in water from pipes, canal s, sprinkler s, or other man-made means, rather than relying on rainfall alone.

Places that have sparse or seasonal rainfall could not sustain agriculture without irrigation. In areas that have irregular precipitation , irrigation improve s crop growth and quality. By allowing farmer s to grow crops on a consistent schedule, irrigation also creates more reliable food supplies.

Ancient civilization s in many parts of the world practiced irrigation. In fact, civilization would probably not be possible without some form of irrigation.

The earliest form of irrigation probably involved people carrying buckets of water from wells or rivers to pour on their crops. As better techniques developed, societies in Egypt and China built irrigation canals, dam s, dike s, and water storage facilities. Ancient Rome built structures called aqueduct s to carry water from snowmelt in the Alps to cities and towns in the valleys below. This water was used for drinking, washing, and irrigation.

Modern irrigation systems use reservoir s, tanks, and wells to supply water for crops. Reservoirs include aquifer s, basins that collect snowmelt, lake s, and basins created by dams.

Canals or pipeline s carry the water from reservoirs to fields. Canals and pipelines, just like the ancient Roman aqueducts, often rely on the force of gravity. Pumps may also move water from reservoirs to fields. Crops are irrigated by several methods: flooding an entire field, channeling water between rows of plants, spraying water through large sprinklers, or letting water drop onto plants through holes in pipes. Letting water drop onto plants through holes in pipes, known as drip irrigation , is considered one of the most efficient methods of irrigation.

Drip irrigation focuses the water onto the plant itself. Other methods can waste water by letting it absorb into the ground where there are no plants.

Water can also evaporate into the air when sprayed through sprinklers. During the twentieth century, the amount of irrigated land in the world doubled. An estimated 18 percent of the worlds cropland is now irrigated. This expansion has occurred mainly in Asia, Africa, and South America.

In spite of some very wet weather, this center pivot in southern Wisconsin is running. Irrigation has been growing in the Midwest in recent years and it could be effecting the transport of agricultural chemicals to streams. Skip to main content. Search Search. Water Science School. Irrigation Water Use.

Get water-use data. Water Use Information by Topic Learn more. Science Center Objects Overview Related Science Publications Multimedia Throughout the world, irrigation water for agriculture, or growing crops is probably the most important use of water except for drinking and washing a smelly dog, perhaps. More topics relating to irrigation water use:. Date published: August 30, Filter Total Items: 6.

Year Select Year Apply Filter. Date published: June 8, Note: This section of the Water Science School discusses the Date published: June 18, Date published: June 12, Below are publications related to irrigation water use. Dieter, Cheryl A.