Center pivot irrigation

Center pivot irrigation

Center-pivot irrigation , also called circle irrigation, is a method of crop irrigation in which equipment rotates around a pivot...

 in Saudi Arabia

Saudi Arabia

The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...

is typical of many isolated irrigation

Irrigation

Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 projects scattered throughout the arid

Arid

A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...

 and hyper-arid regions of the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. Fossil water

Fossil water

Fossil water or paleowater is groundwater that has remained sealed in an aquifer for a long period of time. Water can rest underground in "fossil aquifers" for thousands or even millions of years...

 is mined from depths as great as 1 km (3,000 ft), pumped to the surface, and distributed via large centre pivot irrigation feeds. The circles of green irrigated vegetation may comprise a variety of agricultural commodities from alfalfa

Alfalfa

Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

 to wheat

Wheat

Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

. Diameters of the normally circular fields range from a few hundred metres to as much as 3 km (1.9 mi).